Hard Dodgers

[Tony G]

I thought this thread could use a new post just to keep it alive.

CAUTION! These are pretty rough to look at. It was a mock up we did last summer just to get a 'feel' for the hard dodger in place and to check some lines, egress, ect.. This is only the first attempt and revisions will be absolutely necessary. Lately I'm leaning toward something like the new Trintellas are sporting if it can blend well with the Alberg lines. I don't know if any design will blend seamlessly so I'm thinking about designs with function and utlity.

I know we've discussed dodgers before elsewhere on this forum, but does anyone care to add their two cents? Don't hold back.

[Tony G]

Oops. Missed one

[ebb]

Hey Tony,
That swept-back will shed a comber for sure.

Here's a couple super resource sites to explore. If you haven't already:
www.iversonsdesign.com/dodgers.html
marshalldesign.blogspot.com/2007/04/hard-dodger-test.html
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later post:


(That second site seems not to blue up. So here's the title on google:
Marshall Design: Hard Dodgers for cruising sailboats. Custom...
Have to type it all...
Worth the visit. Get in and view the 'Album'. Has shots of 'unknown designer' dodgers that don't quite make it according to Marshall....
He's right! Hit the 'Slideshow' bar.)
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I am, of course partial to the WRAP style - he has cleared up a 'design' problem for me! His sharing attitude makes this blog a great tool imco.

:D ran across a sailor's blog who refered to it as 'grog'

[Tony G]

Ebb

I haven't been to the Iverson site in some time. 'Pretty sure we stumbled across it when searching for design ideas but, to tell the truth, I'd forgotten all about it. The Marshall Design site was a new one for me though. If I don't hurry up and build one I'll just vacilate between a number of designs hoping to somehow get the best of every design in one unit. What did Commander Pete once write? Perfection is the enemy of progress. Something like that...

The wrapper! They do have a 'flow' or fluid nature about them don't they? Che had a nice feel to her dodger. Do you think it could be pulled off in a large enough size that folks like you or I could maneuver under it? Don't get me wrong, we're all about curves here. But a 'fuller' design like the dodgers Revival or Uhuru sports would lend itself well to egress, cabin top clutches and winches. After all, I'm not only looking for protection but also an extension to the cabin proper. A nice porch if you will. From there it would be a simple process to fully enclose the cockpit for crappy anchorages as long as the ground tackle holds.

Wish I was a little ( alot! ) more photoshop savy so I could pop ideas on and off with a couple of key strokes versus drawing everything out by hand.

Wudda you think? Anyone? Anyone?

[ebb]

I am in the wrap camp of sea dodgers.
In ebb's gallery you see my attempt in post #231.
Don't have anything really against the cab style. There are some nice looking ones - and they allow more volume on top of the hatch area for the winch(s), handle turning, stoppers, line and lunches. On top you can mount solar panels easier too.

Steve Marshall's generous BLUE CAD drawing of the wrap style dodger is just about all anybody needs to flesh out two wrap panels for an Ariel. His curves are nearly if not actually radiuses. The windshield part of the dodger on Little Gull is flattened in the middle - not a compass arch. The surface-curve is flat though, because sheet polycarbonate is going to be cold bent on it. If we un-wrap Little Gull's windscreen it is about 8' long tip to tip. Full height in the middle without the seahood cutout is about 2'. And would look like one of Marshall's eye shapes on the blue CAD.

Marshall's CAD shows that a dodger can be made of two sweeps of some thin material. In playing around with a dinghy form last year I discovered stitch and glue. You take thin meranti plywood, invent edge curves that two edges can share, then bind them together by punching a series of two holes opposite and use picture wire to twist them close. Then fillet and tab the two together. Fantabulous! When covered overall on both sides with fiberglass cloth you have made a shell that essentially is

very strong. And very light.

I think a similar technique can be used to make a wrap dodger for an Ariel. I don't think you have to use the radius form that Marshall shows but bend the sheet into a wider arch with tighter curves at the corners that gets more vertical going down to the coamings. I have always assumed that a collapsible pramhood was the way to go for L.G's top - a kind of hybrid - but Marshall's CAD definitely shows the possibility that the form can be tweeked to allow that all-important corner seating in the Ariel cockpit under a hard hood. Not that he shows this actually, but looking at the layout of the parts of his blue wrap dodger you can imagine playing with those curves to harden them up a bit, flatten the arch, put tighter curves in at the sides, have more vertical sides from the coamings on up.*

Plywood (flat-wrap) can be bent, but it also can be twisted. I use cheap door skin to find the curves on a full size MODEL. You can staple, glue-melt, tape, and cut it with a utility knife until you find the form. The top wrap over the c'way can be angled up more for the Ariel than what Marshall's CAD shows.** The Ariel bridge deck impedes access below so you know the hood top has to tilt higher to allow a bent human to get all his legs in the door.

However if your design has bends too radical for plywood, you can make a form up out of urethane insulation foam, sculpt the block, and make a fiberglass one.
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After some frustrating research looking for dealers I ID'ed a polycarbonate that is treated for UV. It cuts down on UV coming through the material and doubles its life exposed to the sun. One brand name is Makrolon SL (SunLight). It is clear and can be heated to form it if necessary to get a curve tighter than its cold bending limit.
The only ready source I found was a generic UV inhibited sheet from McMasterCarr. The order-taker thought it was Makrolon, but the polyethylene protect film on the sheet is blank.
Also found out that abrasion resistant polycarb actually is a laminate. It cannot be heat formed, cannot be cold bent either. I wanted a bronze tint - it exists - but McMCarr doesn't have it, so I'm going with 1/4" clear UV treated.

Tony, Good Luck On The Dodger!!!
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*the downloads Marshall allows you to get of his Blue Dodger CAD are full 8 1/2 X 11. Means you can cut mini patterns out of cardboard. Play with the shapes. Tweek and trim.

**I have not tried this: it occurs to me that it would be fairly easy to introduce a more squarish wrap form over the cockpit if there was an intermediary wrap between the rounded windscxreen first wrap and the third wrap over the bridgedeck. A three-wrap dodger. It would also be stronger because of the angle joins, that in effect work as ribs.:p
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The Steve Marshall Wrap Dodger has a lot going for it. I would do a quick simple live mockup on my Ariel to see if upright seating in the corners is possible as designed. I'm convinced that the rounded form will shrug off green water better than any other shape. I'm convinced the shape will get you volume over the companionway and slip wind better in the same way. Lowest windage of any other form.
Aside from purchasing plans if available, Marshall might be approached for a group order. IF his Dodger can be supplied as a stitch-and-glue it might ship flat at reasonable expense if you feel you can assemble and glass it. The Dodger would be semi custom in that the bottom is cut to fit individual coach roofs. Two or three already assembled without trim and rails might fit together for shipment to a central point and pickup up by people.
I'm absolutely convinced that a usable dodger will MORE THAN DOUBLE the livability, the comfort, the safety of the Ariel. And convinced that the 'bubble' form is the least obtrusive hard-top addition you can add to an Ariel. If painted a darker color than the topsides it would virtually disappear to the viewer and not intrude too much on the Ariel's pretty looks!
All imco. Don't know Marshall's legitimacy, expertise nor rep. OR $$$.

[ebb]

Would like to call your attention to a discussion on Tony's
"Fruits of my Labor" GALLERY thread Post 241.... PAGE 17.
The subject of hard dodgers has come up again
and even if you are just vaguely interested, there may be new info here.

[Tony G]

Ebb

I'm starting to 'feel' the whole wrap thing. I'm currently thinking a foam cored shape coupld be made soft like a canvas dodger as far as lines and feel go. But with the added strength of a composit build you can stand/ sit on use it for mounting solar panels or disco balls.

Here's the dangerous part....I', also thinking about doing away with the teak cockpit coamings and do a composit coaming integrated with the winch islands and topped with a nice teak cap to balance with the toe rail and rub rail that has already been cut and shaped. I know some may feel this is going too far. Trust me we'll do a mock up before any final decisions are made.

WARNING: this is ugly by today's digital standards.

[commanderpete]

There is a thread on Sailing Anarchy with photos of some hard dodgers

http://forums.sailinganarchy.com/index.php?showtopic=63965

Would come in handy sometimes

[commanderpete]

I've got something like this in mind

[ebb]

That's a great drawing there. Tony.

Just weighed the stand alone windscreen part of my dodger (the only part, so far) on the El Cheapo bathroom scale.
20 pounds. That's with HUGE cutouts for the goggle-eyed polycarb lights.

I knew it was heavy because I did too many layers of X-matt over the 1/2" divinylcell core. The overall thickness is about 3/4". Looking back at the layup I shoulda done cloth. And I'm positive it should have been vacuum-bagged - which I was unwilling to try. Too much epoxy to glass was used. That's the problem with unsupervised amateur one-off production.

I'm going to try to grind away on it, but that won't lighten it much at this point.

The stitch-and glue method would make that same windscreen, just as strong and much more graceful and shippy, at 1/3rd the weight. Probably even lighter if materials were selected correct.

Weights add up.
I'm convinced that S & G 'wrap style' is the best method for the lightest hard dodger.

The finished radical curved shape at a little over 1/4" thickness would easily allow standing on and mounting of equipment. Don't forget to put a light under it!
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By the by, if you do type in "stitch and glue hard dodger" or something like that - you will not come up with true sprung panel dodger. You will come up with a pilot house inspired enclosure. Marshall's web site does appear, but he is the only one offering the wrap or sprung panel hard dodger. And I'm not even sure if he offers a meranti or okume version. Kayaks and yacht dinghy's have for many years been built by the stitch-and-glue method. It caused a true revolution in small-shop boat building. It is a supremely EASY construction method. It is NOT possible that a similar method has not been used for a doghouse on a pocket cruiser.
If not, the time has surely arrived !!!

[Tony G]

Ebb

The current train of thought has me thinking about making a full sized, stitch and glue form that will serve as a male plug/form for vacuum bagging the actual piece. I haven't ruminated enough yet to determine if I'd actually come out ahead taking that route but it seems to make sense to me. Wow! That should be enough to scare me straight!

One thing I did notice while rumaging through some pictures the other night is the wrap version looks alot like Yves Gelinas fire hose dodger, which got some attention on this forum a while back. The shape of things to come, perhaps?

Anyone ou there have a 4' model of an Ariel?

Hey! Wait a minute...isn't this all unsupervised amateur one-off production?!?

[ebb]

:DTony,
As I was intimating.
I believe that a curved shell will be AS STRONG as any foam composite.
My foam composite has an unavoidable CLUNKY SWARTZENEGGER look to it.
In contrast, a thin stitch-and-glue will have a SLIM and COMELY appearance.:o

I believe that even in the modest parameters of our Ariel coach-roof a tall enough WRAP-STYLE dodger can be constructed.
The wrap-style dodger has couple of huge arguements going for it, namely

1) It is the LIGHTEST CONSTRUCTION possible for its volume. Most important consideration for the pocket-cruiser.
2) It will shrug off GREEN COMBERS, big friggin water, much better than an upright pickup truck cab style of windscreen. Of course that's theory. But important theory.
3) Windage is often our last consideration. But again, slipping big wind is as important as slipping water. A top-heavy pocket cruiser could be a dog.
The rounded form would be better at its job than a square form.


I believe the rounded form DOES NOT HAVE TO LOOK LIKE A CULVERT.
I think Marshall's BLUE DODGER shows this possibility. And I believe that experimenting with that form will produce an esthetic and pleasing form.

Geoff's Dodger (which see) is the extreme form of truck-cab. The form can be streamlined: The windscreen slanted more, corners rounded, the top rounded, the enclosure lowered to a comfortable minimum for seating and entry. And imco the roof rteally should be TILTED FORWARD - in other words the cockpit side of the enclousure tilted up. A yacht designer (?) once pointed out that if you take a straight line from the BOW FITTING and run it over the roof of the proposed dodger you will get the correct and most pleasing angle the dodger top should be. Not making that up! But it is an easy place to begin when drawing up possible designs.
Subjectively the truck cab form has an appealing cocktails in the afternoon quality. Or breaking for sandwiches on a broad reach in 5 knots with melodic jazz coming from the speakers under the roof.
While the french 'culverteaux' is more the slippery young singlehand around the world style.

Important: Where is the boom in all this? If you are thinking of a stand-up cockpit like Little Gull will have then seeing over any dodger will not be a problem. That's if you sail standing up. But sitting could. Be a problem. Sitting in the seat might not be possible while sailing in some conditions. May have to sit on the COAMING to see forward around the dodger! A dodger that REDUCES IN BULK or volume going forward will make looking around it that much easier. Wide coaming top sure feeling good right now, huh??!

The smaller boats to gain headroom get into trouble with all kind of awkward shape. The marina is full of them. The europeans, especially the brits and the french have NEVER figured this problem out. It's our responsibility to come up with the better solution - not only for this dodger thing but also for our small sailboat's interior.

I've looked at thousands of pictures of boat interiors and dodgers over the years and come to the conclusion that we westerners are the ONLY tribe that understands COMFORT aboard a pocket cruiser. Comfort in terms of design and convenience and looks.

Your picture of the yacht in #2 of this thread sure looks like a TRUCK CAB that has been morphed into a GREAT LOOKING DODGER. It is on a larger boat. But it appears well rounded. Looks like it has no projections. AND it looks like its top is tilted and inclined toward the bow.

May the epoxy gods look kindly on ya!

[ebb]

The dilemma: round or square?
On going back to Steve Marshall's blog and looking again at his 45 public shots....
On the top row we are treated to an actual wrap dodger install. There is adequate detail to be able to imagine this dodger on an Ariel. And it does look like this design would allow headroom in the corners of an Ariel cockpit - maybe NOT? A full size informal mockup would be needed to be sure.
Marshall seems to say the dodger is a foamcore composite? It doesn't look heavy. We do get an interior shot We do get to see the dodger installed in a very cropped shot.
My purely subjective feeling is that, as shown, it wouldn't be appealing on the Ariel unless it was tilted up in the cockpit area. As I keep saying. It also is easy to imagine the sides going out of curve and straightening quite a bit from the coamings up to allow that tilting. The 'top' may even need to be shortened to allow EASY exit/entry below.
If the dodger is part of a cockpit privacy/wind/rain enclosure, that needs consideration in the design. Another argument for a more squarish shape.

Imco..This particular Marshall wrap dodger also needs more visability THROUGH it.
Another good thing the truck-cab dodger has is the option for flat glass lights.
That would make for distortion free visuals. A big plus. That would mean the glass could be in at least THREE pieces, allowing the center to be opened for ventilation. There is no reason why glass couldn't be used for the center, with lexan used for the sides if curving was needed.

One thing for sure, this Aussie boatbuilder shows some awesome craftmanship!
There is in his gallery a bunch of great hints and ideas.
His visuals are a big help in making the decision.:cool:

[Tony G]

How about a big square peg in a little round hole? Naw. Already been done.

I believe you are starting to see the dilema I've been battling. A 'softened' cab could look very nice and give lots of protected room. A 'hardened' wrap may asthetically fit our squabish Ariel cabin. The best traits of both designs incorporated into one cap may result in a trade off that effects a sum that is less than both components. Life's too short to own an ugly boat.:D (gratuitus smiley)

Do I understand correctly that you feel a foam cored build is heavier than say a wood cored jobbie? I'm talking about a 1/4" foam with a skin inner and outer layer of course. And I should add I'm thinking about a wrap style in this post. So, even though it isn't a 'heavily built' structure it would gather a significant amount of strength from the mating curved surfaces. In one of the designs Marshall incorporates a stainless aft grab handle and a couple of forward running JC bars. He comments that each strengthens the other and its inclusion only makes sense.

Also, I tried to convey some roundness in that Daliesque drawing above. I know, it's hard to make out but here it is...That little arc that spans from the coaming breakwater up and aft toward the middle of the trailing edge of the dodger is meant to indicate where the dodger flairs out from the side plane that matches the cabin sides to the plane that matches cockpit coamings. Thereby introducing another mating curved surface which would hopefully not only strengthen the dodger but also help shed water away from the cockpit a little more smoothly. Add to that, dare I say, if I do build fiberglass break waters and coamings and winch islands it would blend the visual field of much of the aft half of the boat together. That way the added horizontal runs of wood would (ha-ha) lengthen the boat. The line off of the top of the dodger could be drawen to the front of the bowsprit not just the stemfitting. Maybe even put it in a parallel plane to the rest of the cabin?

[ebb]

Caps of mahogany would look great and help dramatise the boat above the sheer.

I think that wrap dodger of Marshall's is probably a vacuum-bagged 1/4" or 3/8" pvc foam core with a number of layers of hightech cloth on both sides. A composite foamcore sandwich. A professional probably uses stinkola vinylester because he can - and it cuts $$$. Incredibly expensive closedcell pvc foam comes in a range of thicknesses. But the thicker the foam the stiffer the structure - because of the separation of the skins. If the skins are thin, the closer they are the more flexible the shell.

Another sandwich has wood ply in the middle between single 6oz or 10oz layers of glass. Whatever Marshall uses it isn't very thick. If it is a plycore Stitch-and Glue composite - and I don't believe so - the stiffness of the plywood would make a much stronger shell than foamcore. Attaching stuff to the dodger will be easier too. Point loads less of a problem.
Swing a single jack at the top. The hammer will bounce off the S&G. I'd take the bet that you'd punch a hole in a foam composite. Unless it's a heavy multi layer glass or a pricey graphite/kevlar lamination.
In the USA the reasonably priced meranti mahogany ply comes 1/8" 1/4" and on up. Sometimes these sizes are a slightly thinner mm dimensions.
Problem is shipping it in 4X8 sheets - mucho $$$ - although you could have a design plan using lengths no longer than 4 feet. I believe UPS will do 4X4 sheets.
There must be a dozen sites that have clever sheet plywood scarfing jigs.

Here's an observation:
How many composite fiberglass kayaks are there?
NONE.
There are rotomolded gascan kayaks but no foam composites. And the reason is the weight to strength ratio.
Look at dinghy's. The fiberglass ones are ALWAYS heavier than the stitch-and-glue. Imagine a six or seven foot S&G dinghy. It is a bowl shape.
The whole dinghy weighs between 40 and 50 pounds. Light as a feather, strong as a helmet. The glass sandwich will weigh in over 100 pounds.
Imagine that the dodger is a similar bowl shape as the dinghy. Ok, so it has big openings, but it is rigidly attached on one side to a very strong surface (the deck) - while in comparison the dinghy is free standing. You double up on the dinghy's sheer for more stiffness.
You can double up on the dodger's opening in the same way.

And I can't get away from the round forms because no matter what the composite they are always inherently stronger than flat forms.

The plycore sandwich is naturally stiff. While divinylcell is stiff it in no way compares in breaking strength to meranti. Therefor you have to have more cloth or matt layers - and resulting weight - for any strength that approachs that S&G shell - which is barely over 1/4" thick!!! (As I see it.)

Karumba!



Not only THAT but
S$G is much easier to do and much less labor than a foam composite.
imco as aways

[Steve M]

Hi all,
I received an indicator that my blog site was being discussed by this group. So I thought I might chime in and offer some help with any questions you have.
I noted in some of your discussions that there was conjecture as to what materials I was actually using, well to answer this, most of the Dodgers that I have built, and that you see in the pictures were built in female molds, that were constructed on top of the individual boats.
The mold was then removed to a suitable place and a fiberglass and cored dodger was constructed inside it.
The female molds I produced were one-shot affairs only, possibly a second dodger could have been pulled from them but that was not the intention.
These female molds were built from very cheap interior type of shiny surface plywood or masonite, with the shiny side facing in. They were assembled on the boat, after much cutting and hacking and trimming and guessing and re-cutting.
The adjoining edges were basically, and roughly glassed together with fast epoxy every two or 3 inches, then a rough wooden framework was glassed over this to lock in the general shape.
When the female mold was removed to the workshop the interior joins were bogged and filleted, sanded smooth and sealed.
Window inserts were placed into the mold, which would create rebates for the Windows.
This process produced a reasonably good dodger and as light or as heavy as you care to make it dependent on the core material and the lamentations used.
There was however one really bad downside to this method and that was the effect the weather played on the mould.
Invariably, changes in humidity and temperature while building a mould would cause the material used to distort and buckle and although these distortions were not really great they were not acceptable for a finished job. If you copped a bit of rain halfway through you could darn near chuck the whole thing away.
This fact alone, was what stopped me producing these dodges in Washington (Seattle). A place where they were really desirable to have.
Since those early days I have spent lots of time in manipulating flat panels be they composite or plywood and coupled with my learning to use CAD some years back it has totally turned the whole dodger thing around for me.
Where as before, I had to do drawing after drawing by hand, and then had to do a mock up on the boat and still hope that it was right, now, once I have a few basic measurements and have established the right parameters I can draw up a complete dodger and cut it and slice it in any direction I like which allows me to create a jig surface.
Coupled with this of course is the ability to do panel unrolled.

This feature in itself within CAD (or it leased the one I use) is really fantastic and simplifies the designing job immensely.
If the designer has a good knowledge of the way materials behave, and works within the boundaries of the materials, then the item can be a complete success and without great difficulty to build.
Rather than ramble on, I'd be happy to answer any questions (if I can) that you may have.
I posted some more pictures on my blog and will try and post some more of a female mold being constructed

Steve Marshall

[ebb]

Thanks for the visit Steve.
Amazing you are on the other side of the globe and can give us your neighborly input and experience. That's just great! You whippersnappers have the great benefit of CAD. Envy that ability.

Tony and I - and Commander Pete for sanity sake - having an active discussion on the subject IS what this Pearson Ariel/Commander Association tech forum is ALL about.
From the 'hit' count we gabbers are obviously getting listened to by other boat owners who probably want a dodger - whether they are cruisers or weekenders.
I wish more A/C owners would join in, give this discussion more legitamacy. It's a worthy subject that nobody could not have an opinion on - especially which style is more appealing.

Now we have an international contributor, a pro who is willing to share his experiences with us!

If you want a hard dodger, and you are a classic plastic boat owner, you are probably not made out of money and have to make one yourself.
Steve Marshall 'says', take your small tools down to the boat and some panels and start messing around making some frames, some bending forms and see what you come up with in terms of the space you want. The boat will talk to you.
If you like the idea of wrap or bent panels, you make some bending frames, tack and cross brace them to the coach roof and the bridgedeck (you can fill the holes back in later) and start forming that dream dodger.

Tony is showing how to make a 3D sketch.
Not sure how his form translates into a female mold but if Marshall says it can be done ......then make it so!

To proceed toward a female mold:
that is when you take your think pieces and replace them what will be the inside surface with 1/8" hard-board.
Even here you can make twin holes and stitch panel seams together with wire when bending together more than one panel edge to edge.

When you got the overall shape you want:
Before you remove anything you stabilize the top with cut to fit plywood and two-by. You build another frame on the TOP and SIDES of your model to keep it in that shape - because the original frame the skin was built on is of no more use. It's like bridge-work You are ofcourse making the cradle and legs that will be under the curved form that when it's turned over you will be laminating INTO.

[When you get a book on stitch-and-glue, you see that after tacking your shape together with epoxy goop, you snip away and pull the the wire and proceed to make beautiful fillet seams. I would get a book on S&G just to understand the process for the dodger mold.]

Fiberglass and foam in a female mold is another kettle of fish.
Using Marshall's female mold idea you'll be building up the dodger from the inside - your first layer inside is what will be seen on the finished product outside. A boat building shop would spray in a gel coat on a well prepared surface. (I have heard of as many as 20 coats of carnuba, each polished, plus mold release spray... to prep the mold.)

A boat owner will be using the mold just once, so it is possible to be more casual. In fact, no matter how well you prep the mold, it will probably have to be disassembled to get it off your new dodger.
It is possible to make the dodger in a female mold with epoxy. Your first layers will be X-matt, altho I have heard of an epoxy 'gelcoat' that could possibly be rolled on the mold befor the matt went in. Haven't done it. if you don't start with color you will have a lot more surface filling and finishing to do before painting.
If you have some experience with poly and vinylester then that is probably the way to go with the female mold method. Sounds like that's what Steve Marshall does with most of his.

The female mold with all its bracing and understructure will be quite huge. The dodger itself will also be multilayered and a lot of pieces of cloth, matt and foam sheet. I think polyester takes more experience, while epoxy is more forgiving and less lethal.
Personally, even tho it's so much more expensive, I would go with 100% solids no blush epoxy. I think it's easier for a first or second-timer to use.

If I had any time left to experiment, I am convinced that a wrap style bent panel MOLDLESS dodger out of meranti would be the easiest and most gratifying way for an amateur (don't take that negatively!) or a first timer to make. Check out stitch-and-glue DINGHY sites and you'll see what I mean. The kayak DIY sites are often too esoteric, but often what THEY do with the method is amazing!

Thanks for dodging in, Steve!:D

[Tony G]

Ditto that thanks from over here too. It's always good to get the input from someone that has been there-done that. I'm always surprised at the amount of information one can glean from this forum.

Unfortunately, for me anyways, it hasn't made the decision any easier. Laying a core into a female mould sounds like it could be tricky. I don't know why but past experience leads me to believe so. Vacuum bagging into a female mould would surely be more difficult than 'over' a male mould when we're talking about a pull this size. After all, I am amatuer hour. A smooth outer surface is a nice starting point. That coupled with the ease of adding 'rebates' for the windows and other 'built-ins' makes an attractive argument for that route.

Does a 1/4" to 3/8" super light, super flexible, super cheap core material exist. Weight is an issue, after all. If you went thinner I suppose one could easily add a few carefully placed stingers to stiffen things up a bit. And I do like the stainless grab bars incorporated into the design.

Gawd I wish I had the time and grey matter to invest in learning a CAD program! While I like the 'real wrap' design I think a curve that matches the curve of the cabin top just aft of the mast is most graceful and yet sexy. We already know the arc of the cabin top truely compliments that curve and would make a nice top for a dodger. So far all over this rebuild I've been stealing curves and borrowing angles from other parts of our boats to incorporate into my ideas. I really believe that it adds continuity. Just my opinion, folks. Shoot it full of holes.

I don't feel so bad about drawing everything 'longhand' now that I heard the real deal has done it too. HA! Take that computer nerds!:D

[Steve M]

Hi Ebb and Tony,
just to expand a little more on my previous comments.
The method I described of creating a female mold, is for me, totally in the past.
As as I've worked much more now, with flat panels and found different ways to form them, other aspects have shown themselves which can certainly speed up the job.
The method I now use, and I am describing with pictures in my book, is a mixture of post-forming glassed flat panels, and stitch and glue.
Ill briefly describe the billabong style.
This style uses a series of flat panels all of which are cut from 6 mm (1/4")
There will be an inner and outer piece, for each panel, which when laminated will give a total of 1/2".
The outer layer being cut with a slightly larger window opening (say 30 mm) to allow for the rebate. This total thickness of half inch ply is really negligible in weight as most of the panels are cut out for windows, and this thickness is required to provide a rebate and for other reasons.
Now as an example of post forming, and this is not the complete picture but just to give you an idea
The Billabong Style
Cut out all of the inner 6mm flat panels, cutting their window holes (which of course is smaller than the window itself to create a flange ) Round the edge of all the window openings on the inside face only.
Cut the outer 6 mm panels (we are assuming a light weight good-quality marine plywood is being used)
Position and glue on (with epoxy) the outer panels to the inner panels at the appropriate places.
At this stage all the panels are separate squares or rectangles, with window holes and rebates.
Now with the Master face panel Patten, drawn on the table which will sort of look like a boomerang made from a series of squares.
Cover the table in clear plastic, place the panels, outer face down, in their appropriate positions edge to edge and glue together to form that one big boomerang shape.
All of these panels must follow the Master Patten precisely.
So you will now have the inner faces all facing up towards you, and all glued together along there are joining edges
These will all be just square on butt joints and certainly don't need to be fancy in anyway.
They do need to seal the gap between the individual panels at best, and must not allow resin to drain through.
Sand over this entire surface so there's not blobs and lumps of glue sticking up.
Now, glass over this entire inner surface with 600 g bi axial (do not use less weight than this) making sure the glass goes smoothly down into the window cutouts, and nicely covers the radius edge.
Just let the glass hang on through at this window .opening but keep it in nice and neat to the each will be trimmed later on
this inner surface can now be filled and sanded smooth. Leave a strip 30 mm around the entire top edge unsanded and unpainted.
Leave the same kind of unfinished surface around the entire bottom edge but about 60 mills wide.
I specify using epoxy when glassing or gluing plywood as the bond is far far greater than polyester or VE
when this whole business has properly cured off, about two days in good weather, the whole thing can be carefully turned over, so now the glassed face is down.
You will now go around the entire top edge of your plywood and glassed panel and with a planer or grinder feather away the top edge down to a thickness of about 3/8 of an inch, and down the face about 2 1/2 inches Any resin gobs or blobs can be removed, and the glass that came through the window hole can be trimmed off so that you should have a nice neat rebate with fibre glass running right up to the inside edge.
So now you've got a big partially fibre glassed boomerang shaped thing on your table with nice neat window cutouts. Now this next step takes utmost care.
You will mark out a series of lines parallel to each other and equally spaced down what appears to be the pillars of your dodger face (that is the sections that you butt joined together, between the window openings)
you will then set up your skill saw, the smallest one you have with the narrowest blade and proceed to cut down these lines to a depth of about 3/8 of an inch or less.
This Kerffing of the outer plywood face allows the glass and plywood panel to be bent smoothly on what is to become radius corners of your dodger.
The positioning in the spacing of these lines is shown in my plans but you can experiment yourself you will also need to experiment with the depth on a peice plywood that has been fiber glassed. Note this test piece of ply must have its grain orientation identical to the way yours is on your job to deeper cut and you will get creases showing on the inside. To shallow a cut and you'll have difficulty in bending to the point where it may suddenly break on you. So do the tests.
My plans will show a-based pattern and a simple jig all of which are done from chipboard. The front face panel you have just created, is then bent around with great care to conform to the mark out bases line and if all is correct it will rest up against your chipboard jig. The grooves you have cut in the pillars can then be filled back with epoxy filler (Micro fibers and epoxy resin)
The other surface can then be fiber glassed, with 600 g DB, taking extra care to a good job on the pillars and.and don't gob resin into the window rebates.
The Cambered Top
The cambered top use's a somewhat similar method and there are some tricks here to really create a good and simple finish.
Firstly lightness is of great importance, however this hard dodger will be stood on and possibly fallen onto so it needs to be gutsy it's possibly going to support solar panels, resist possibly the boom falling on it, and God forbid big waves dropping onto it.
So to this end a thin section is not an option.
So options are (low cost included here ) plastic honycomb "Nida Core" "Poly Core" "Plascore" I rule out virtually all of the foam cores because of their current excessive cost.
The plastic honeycomb should cost between $60 and $80 for a full 8x4 sheet at 5/8 thick.
If your interested I can explain in general manner this top making which is way more simple than the front.
There are many little details Iv left out so as not to confuse.
I use a word recognition program ("Dragon Naturally Seaking") if you find some strange words in the all this text.
ps I did get some pics onto my blog last night of female molding but as I say I wouldn't push that method any more
Steve Marshall

[ebb]

Steve. that's one of the greatest process posts of all time here.
I'm a DIY fan, and try to have complete thoughts on subjects - so I'm impressed and for myself thank you for it!

The female mold process does seem to be labor intensive.
I used a similar process on a male mold for the windscreen portion of LittleGull's dodger. Foam core laminate. Unless experienced with a good plan and access to full inventory of materials it leads to overbuilding and overweight. I used X-matt but should have used woven cloth.

We have a great moderately priced phenolic glued phillipine mahogany plywood available here. It is rated to British standards and is usually sold as Hydroply and Aquaply. It is a planet plywood, depending on the source is available in mm or inches. The veneers are very thin. The mm version of 1/4" is thinner than 1/4" but still has 5 plys. I have seen 3 ply 1/4" meranti, but won't buy it even if it is BS1088. Meranti is cheaper and more durable (rot resistant) than okume, a popular and lighter plywood used by kayak builders. Meranti is a much cleaner stronger plywood than marine fir ply. And made much much better than what is produced in the States. Using meranti will make your project look that much better.

The Billabong style dodger, and the method Steve describes would work great for Tony's cab dodger. The method is, as I keep saying, very much like stitch-and-glue building. In fact the same wiring of panels trick can be used.
Because the panels are so thin, strength is gained in corners with the use of epoxy fillets and the ultimate covering of the whole structure with cloth, inside and out. In fact, if I understand it, the whole hard dodger could be made and fitted to the coachroof before the final whole cloth layers is applied. Or perhaps the inside could have the tie layer of cloth applied and the outside done after carpentry and fitting.

I naturally like the other Blue wrap style.
Because the panels are all bent into curves the structure is inherently simpler, stiffer and stronger.
Imco the windscreen light could be slabbed on (without rebate) to a single 1/4" bend. Let's call it a racing version of a hard dodger.

The problem with the Ariel is its size. It already has a two-bump coachroof. A hard dodger will add an unintended design change to the visual volume of the sailboat. At this moment in time a fabric and tube pram dodger is more acceptable to the eye. One thing I've noticed is that we see canvas as separate from the boat's lines. It helps if the fabric is a darker color. When we make smooth and beautyful additions to a sailboat in the form of a hard dodger, we can get into trouble with the designer's original concept. Hard dodgers are becoming more streamlined and acceptable as a structure, like the fabric pram hood, for itself. In other words, imco, you don't want the dodger to give the impression of a designer pilot house on a pocket cruiser. The Ariel needs a disproportionate tall hard dodger to provide access below.

It's a real problem that I wish we had more to talk about here.


With the flatter 'cambered top' imco a rib or two could be introduced or could be added later where attachment points are known for rails and solar panels.
Honeycombs are the way to go for lightness and insulation.* If this is too tech, then endgrain balsa is still available.

Steve's double 1/4" method of side construction would make a very strong and light structure especially with mm meranti. Polycarbonate rebated into the dodger would make for a very clean looking job. Flatter lights on the Billabong style would allow thicker and stiffer poly. Can consider the poly as a structural component that adds strength and stiffness.
__________________________________________________ _______________________________________________
Cambered top:
* Using a foam or balsa or honeycomb for the core...
do you think you can get away with 1/8" ply on the top and bottom?
It could be possible to get good rigidity in the finished laminate with 1/2" core - 1/8" skins - 10oz cloth top and bottom - glass and epoxy. ???

[Tony G]

Ebb

Let's just forget we ever saw that first attempt (?) at 113's hard dodger. You're absolutely right, the Ariel just does not lend itself well to the 'motor sailer' and pilothouse look. To that extent we're...persuing other avenues.

Why not try to form something that has the room and curves of a soft dodger with the duability and utility of a hard dodger? That's where I'm at now. Date and Time stamp it, tomorrow could be different. :rolleyes:

As far as using 1/8" ply skins over a core-it seemed to work for me. The roof of the hard dodger I started on is pretty stiff even with no other means of support locking it's shape. An even smaller piece I had pulled for a seahood is much more demonstrative of the capabilities of 1/8" ply skins. I actually tried to crack that one but gave up for fear of later regret should I need the part for something else.

Thanks to Steve's input I think 'I have a plan'. Just wish I could spin my drawings in 3D to really get the point driven home.

Of course this is stolen art!
__________________________________
One thing I've noticed is these pics seem to get compressed horizontally when posted. Stretch it a bit and it doesn't really look that punchy or is it paunchy!

[Steve M]

Hi Tony
If you look at the "Foreigner style" dodger on my blog You'll see pretty much exactly what you've drawn. Although I did this, and later, a couple more in this exact style, in a female mold.
Bending thin ply, pre glassed and surfaced on the inside with pre made window openings and rebates would work superbly.
This would go equally well for the top , that is finish the glassing on the inside top surface and fill ready for paint, all done flat on a table.
Flip the top over and bond the core to it getting only one surface of the core wet in the bonding process.
When this combination is bent over a former (say a beefed up frame for a fabric dodger) the uncoated top surface (facing up) opens up naturally.
Balsa and honeycomb are particularly good for this purpose.
The final top layer of glass/ply are glued down onto it and pulled into firm contact while gluing, using tension able webbing straps.
I only use real thin ply for this combination, say 1/8" each side
Note here, and this is important! for any curved surface like the top of Foreigner or the full wrap face panels your ply needs its main surface grain running in the fore and aft or the up down plane,not around or over.
So you need to cut your ply sheet into sections (across the sheet ) and edge join (small simple scarfed join) the 4ft sections.
Im having difficulty explaining this, but if you neglect to do this your ply will tend to dish in when you pull it round a curved former.
You will see one of the pictures shows a "Foreigner style" which I built for a Pearson 36'. the mold pictures show the ply wood orientation clearly.
Even thought this was for a female mold the same thing applies .
Steve Marshall

[ebb]

As this thread threatens to sink into the archival marsh, as these threads do as they get pushed down the list...

This is, for some reason, an amazing LIVELY small sailboat site.

Note that we have had MORE THAN 8000 TECHNICAL POSTS since Bill started counting in this format.
It's been a fantastic resource for yours truely....and a lota fun
And I suppose likewise for all the ghosts who whaft through without even saying HELLO.

I personally want to thank you Steve Marshall for coming in to the pub here and joining the conversation. Your generous sharing EXPERTISE has helped me fer sure!
Great tips.... THANKS:cool:


......more?........

[Steve M]

Hi Ebb
Thanks for that comment.
It really is may pleasure to help when I can.
Hard dodgers sort of be came my passion, as I did many miles protected by them and I know they offer the cruiser a huge benefit
Its hard to describe till you've actually had one in use.
Anyhow good luck with your project,If You get stuck along the way in your drop me an Email

And if I can, Ill help.

Steve Marshall
Marshall Design
steve.marshall@gmail.com

[CapnK]

My apologies, fellas - I haven't been saying much on the topic, just looking at the pictures, reading the posts, and imagining a dodger as I get in and out of the boat every day. :D

I have a giant tarp boom tent that I use over the boat in the summer, when shade is needed. This time of year, shade is abhorrent, to a thin-blooded southerin' boy like me, so I use a tiny dodger tarp - about 4' x 4', with a window in it. It sits over the companionway on rainy dayskeeps water from falling straight in. On sunny days, it's easier to peel back. The whole point of mentioning it is that I've been using it to gauge how high a dodger needs to be, for me, to allow ingress/egress, without a conk on the head every time.

To that end, I had this thought:

How about a cutout in the dodger 'roof', right over the companionway, a 'notch for the noggin'? Our dodger needn't be so high, to allow easier passage of a sailors skull. There'd still be rain protection in the cockpit when sitting to one side, and a small cloth flap could be fit to cover the notch if/when needed; it could even have elastic on its after end, so that it needn't be removed when climbing in/out, but would keep water from falling in?

Excuse the high quality drawing, but I hope it conveys the idea. :)

Steve - have you ever seen anyone do something like this? (And many Thanks! for joining our discussion! :) )

[CapnK]

The notch-covering flap could also be made of a hard material, larger than the notch by a couple inches, attached (hinged) at the forward edge, with fabric at the sides like a bellows. That way it could go up and down easily when climbing in/out, but wouldn't sag with the weight of rain/spray.

[Tony G]

....boy do I feel stupid....

[Steve M]

Hi epiphany
I cannot remember seeing the cut out as shown. I'm sure it would aid access in a low profile dodger but the trade off would be a loss of strength across the back edge and no continuous aft edge grab rail.
This could be partially offset by creating an up tuning rim around the opening of say 2" depth which would also provide water proof rim to a minor extent.
A thing I have seen on a friends boat, and this was around his center cabin hatch.
A rim of bolt rope type sail track was fastend around the front and sides of his hatch onto the deck.close to the hatch base.
A fabric cover with bolt rope edge and thin battens in pockets was slid into this, that when pushed up wards by the hatch being opened formed a wedge.
The batten pockets were positioned to line up with the side edges of the hatch and the batternes supported the fabric over hang that was some 5'' longer than the hatch.
This gave excellent protection from the weather while sailing with the hatch open this same idea might apply to what your suggesting ??
Steve Marshall

[Bill]

The Burns 30 had similar access problems and the fix in the soft dodger was to create a deep U (about a foot wide) in the aftermost tubing with a zippered canvas section that could be flipped back (er, forward). Don't recall if the bottom (forward end) of the U had a support going forward -- the canvass cover may have been adequate.

[CapnK]

Re: the Burns 30 - There's no such thing as an original idea, is there? :D

Steve, your friends hatch cover sounds like it would work well. In my original thinking on a 'cover' of some sort for the opening, I was thinking a batten could be placed in the fabric to hold it up. Bills zipper idea would be workable, too. Heck, I guess the edges of the fabric could be attached with elastic even, just enough to allow your head room getting in and out.

As far as having a 2" lip - that would be a good idea, besides just strengthening the opening. Made to where it goes around the outside edges of the "hard flap", it would serve to keep spray and wind from being able to lift the flap up accidentally.

[Steve M]

Hi all
this I forgot to mention but its a simple way to define the central angles and heights of your projected dodger and allows a view from the side and also is a good way to transfer measurements to your boats drawings that are accurate ( use this for my measurement sheet.)
Take a line like a builders line, bright in colour but not heavy that will sag
Tie one end of line around your mast but able to be moved ,say as a start point,about a foot up from the cabin top.
Pull it out real tight and tie the other end to your back stay(able to be moved up or down)
This, from the side can be viewed as the top of the camber of your dodger (you must be level with the line and abeam of your hatch to view it)

Now move it up or down as suits climb in and out of your hatch way and see how it fits! do you need to contort your body not to hit the line ?? etc

When you've got this line right take a small light piece if stick and with your line real tight (mark the positions on mast and back stay in case it slipsand (stick a little masking tape to prevent slipping)

Place one end of the light stick on the hatch box or where your anticipating the fwd center base of your dodger to be and with a light cloths peg or paper clip, clip the stick to the colored line.
This will be a side view of the central front edge of your dodger (the center screen) tilt it back as required. Re test getting in and out of the hatch .

Measure the distance back from mast back edge to top of the stick at line intercept and the same from bottom,( mast back edge to stick base) measure the length of stick (deck to line intercept )
Measure also the exact vertical height of stick base to line intersect.
Once you've got some lines to work from and that can be repositioned you'll Get a better feel for what you want and be able to repeat the scenario
and better apply your thoughts to paper and with accuracy.
Steve Marshall

[CapnK]

What a great tip! Thanks, Steve! :D

[Tony G]

Just been to Ebb's photo gallery. I think we're going to dig into this idea of a slider on top of the hard dodger. One that has self-draining channels cut in that look much like the PVC channels Ebb cut into his outboard 'hutch'. Look at photos #198, 199, 200. If you continue the channels/drains forward and down to the cabin top where they would exit the bulwark. They could drain off rain, spilled...soda, green water. Given the shape they would lend more strength to the front 'pillars' and being hollow add very little weight. The sliding hatch being of such small dimensions would not take much to make it 'step worthy'. I mean, really, how much time do you really plan to spend walking on top a 44" wide dodger? Barring, of course, any Parrothead activity, xmas parties, impromptu birthday parties, engagment announcements (someone elses') National and other Worldly Holidays.

Wow! This is pretty exhilarating for people like me. Now if only the boat wasn't wrapped in plastic in 15 below zero weather.:(

[CapnK]

Hmm - why make it slide? Just make it tilt, opening from the forward edge...?

In the down/closed position, it would stiffen and strengthen the structure, I'd think...

[ebb]

Hey guys...over here at the end of the bar..

Taking Kurt's idea of a top that needs to be opened to provide more dignified egress to the galley.
His drawing shows that opening.
and Steve is saying that cutting the panel/top will seriously weaken it. True, true.

From the forward corners of the opening put in a couple struts down along side of the sliding hatch.
Right? They won't be in the way of anything. They'll go from the coachroof right next to the slide and up to the corners of the cutout in the dodger - the two legs won't impede the sliding of the hatch.

Won't impede anything going on in under there...Right?

Let's take any bendiness out of the dodger edge and the new opening by trimming it out or doubling it.
Let's play with the position of those legs by moving them back a little to take more of the load. Might work in a couple gussets to make it near impossible to move those corners of the top. Nah, don't like gussets.

AHHH but leave those legs still at the corners, and put in a couple more toward the opening. The first two immobilize the top, The second two support the wings of the top. They probably don't have to be at the end of the cabin top but maybe half way in.... but still bracing those corners.

I think they could be legs las simple as 2x2s. Not panels which would separate that nice space under the dodger. I can't think what would get in the way of these support legs - except the winch handle. Probably arrange the four struts so they are out of the way and nearly unnoticed.

If you are rich enough to have s.s tube grabbers on the dodger, they don't need to be exactly along the outer edge over the cockpit but could be inset to correspond more or less with the struts inside. The struts are locked in to the coachroof. Locating the exterior grabrails near the interior strut join would make for a solid feeling construction.
And the struts could be nice shiney stainless tube too.

If tube works there, the appearance would be more like grab rails and not like structural pieces at all. I'll bet the project would end up almost as rigid as an unbroken no hatch dodger! These vertical grabrails might even work just that way.

Go for it Kurt!

Just throwing this out on the table....;)

[Steve M]

How about this opening support rail.jpg (http://pearsonariel.org/discussion/attachment.php?attachmentid=4708&stc=1&d=1203137260)
Steve Marshall

[ebb]

Spike: BY GEORGE, I THINK HE'S GOT IT!
The key to your cure, ducks.
The missing bloody links, it was...

Drusilla: (indicating Tarot card with an Angel)
...Right in front of us... the whole time! [Buffyverse Dialogue Database]



Steve,
Totally Superb
Unexpected
A Quantum Leap

Don't know what engineering form Steve has here.
It's a kind of truss tube isn't it?
It definitely would fly if the tube was welded.
It's really marvelous!:D
__________________________________________________ _________________________________________________
Can't sleep!
It's the color of the tubing..
That support rail could be made out of 6061T6!!!!!

[CapnK]

Yeppers, that looks great, like it would do the job!

(I need to learn that CAD stuff!!!)

[Tony G]

Kurt

The reason I lean toward a sliding hatch is that head knockin' boom. A blow to the noggin', if it doesn't kill you, will keep you from doing it again. If an accidental jibe blasts off the standing hatch, well, then you have another thing on the boat to fix. Maybe one of those 10" spring 'kickstand' type hatch struts you see on forward hatches would buckle before a calamity happens.

But a forward lifting hatch would be easy enough to do. Much like a cockpit locker lid with the drains is what I'm imagining. All to often I fail to adhere to the KISS methodology. Time to get out the paper and pencil in lieu sound CAD erudition.;)

[ebb]

About the hatch in the dodger.
Steve's CAD shows coamings around the opening - certainly the simplest way - if molded in, or stitch-n-glued, the rise will also provide strength and stiffening.

(Tony was refering to the lid in the rear hutch over the lazarette. I used some pvc channel got thru McMasterCarr to make the channel in the top. It was only used as a form for glassing - didn't become part of the final project. In effect the molding of the fiberglass makes that channel shape into a stiffening rib. It was a complicated way to get what a simpler rising coaming would accomplish. When the lid/hatch is is place, there is nothing for big water to tear off.
When forming the male mold for this construction, the pvc forms are worked into the mold form and the hatch top is cut out later from the laminate lay-up. It's picky but the result comes out very fair - As fair as you make the moldform. Could leave the lid as a plain curved panel - I chose to add a turn down, so the lid extends down into the groove around the opening. I also stiffened the lid with 1/2" pvc foam inside and glassed it in. 1/2" pvc foam bends easy enough and can also be heat formed. Don't think there is anything superior about this, it's just another way to do it.
It was natural to extend the grooves aft and down to mini scuppers because there had to be a way to get water trapped in the groove out.)

I believe the UP coaming is simpler and better.
The hatch when opening it is problematic. The above mentioned hatch on LittleGull behind the cockpit is huge and when opened is very vulnerable. I made it big to get the OB out. I imagine that the hatch will be seldom used. The hatch in the dodger needn't be too large. Do need to get the shoulders in, and there is a big measure of comfort in how much is left opened forward in that opening. Bigger is more convenient.

An UP opening hatch will get in the way. Probably have to open it all the time to go below, it has to be EASY to use.

I'm thinking that a hatch could be devised that would slide open...but not like the usual sliding companionway hatch.
The hatch would be in two pieces hinged across the middle - the middle rises up as you push it forward to open it. That way the hatch is always captured. And if not too tall can probably be left open most of the time. The rise would only be half the length forward of the opening. The hinge maybe would leak a little, maybe the sides too, but could be casually waterproofed with fabric or something when closed. The hatch would be made on top of the dodger, inside the coamings, using SAIL TRACK AND SLIDERS. With another mini coaming just under the hatch, on the inside of the opening, channeling small water away from going below.

That tubetruss surround Steve proposes for the dodger above would work just as well on the BlueWrap style. So I'm going for it. I done seen da light.
.................................................. .................................................. .................................................. ..............................................
later EDIT. Steve's coamings - shown in his cad just above here - leads to another idea:
which is to incorporate cleats or knees INSIDE the coaming.
Consider inner cleats going fore&aft along the top (inside) and curving down to the cabintop. The cleats would also frame the hatch opening - and also at the same time be the upright coaming in way of the opening.
Maybe this can be seen as cantilever or davit framing (using the curve of the top & front of the dodger to create a strong structure.) Probably take the full weight, without deflection, of an atheletic male standing ON the corners of the dodger. Quite possibly, no support posts at the dodger hatch corners needed.
The hatch itself could be a laminated sunbrella (canvas affair) that could be zippered shut during water events. When open, maybe roll it up and velcro.
'Two Cents Worth' just became became Dime A Dozen.......:o
__________________________________________________ ______________________________________________
NEED HELP ON A PROBLEM:

It's about putting polycarbonate on the windscreen.

My windscreen section is a foam composite that is 3/4" thick. I can't see bending and slabbing the polycarb windows to the outside, even if they are now only 1/4" sheet. They have to be rabbeted in. And there's the rub. I've already cut huge openings into the windscreen and I have to figure out some way to do this rabbet stuff its rather radical form. There are no rabbeting bits that will cut a wide enough flange. Even 3/4", if the little 1 horse trim router will swing it, is not wide enough. The reason is that the bolts have to go through the plastic window AND the flange.
There is set-back on those holes and holes set-back from the inner edge. And complicated by the need for expansion of the polycarb, so the cut-out window has to be considerable smaller than the rabbet edge. Absolute minimum is 1/8" all round. Holes through the sheet have to be oversize as well! This all means the minimum flange width HAS to be 1". And around 5/16" depth. Better even wider, like 1 1/4"
The PVC foamcore is structural imco. The polycarb will seat on the foam, I don't see this as a problem, tho I may put a thin layer of glass over it, best way PITA.


Got this damn curved composite wrap.
Anybody think of an easy way to cut that wide rabbet?
Only a small-base trim-router can be used on the curved windscreeen. At the moment I'll go with the widest rabbet bit - establish the depth - and figure out a way to carve the width back that's needed (Dremel tool?).

I know, I know, make a simpler windscreen wrap.
OR slab the poly on to the outside with all the overlap needed.

[Tony G]

The one issue that leads me away from the upturned riser/coaming is the fact you can't get a nice smooth top. Granted it is an easy answere to the issue (KISS). But my reasoning is the slider will be closed nearly all the time anyway. Relative to rebuilding a boat inside and out it would be easy to incorporate the slider mounting into the scupper channels. The channels along with a couple of thoughtfully placed stringers would replace much of the strength compromised by having the cutout. And I never have drifted away from the idea of some sturdy well placed stainless handholds...the JC bars as they're sometimes called.

Besides if it doesn't work we can 'blame' Ebb. This slider idea came from his lazzarette hutch just like my flush cabin ports came from his chain locker.:D

Take one for the team, brother Ebb!!!

[Steve M]

Can you show a picture or 2 of the problem ebb ??
Steve m

[ebb]

Wish I could, Steve.
But if you would step into the front room here, you'll find a couple pix down the hall. Go out to the Pearson Ariel Forums menu page. Click on Gallery. Scroll down to Ebb's Gallery. Click in on page 16 and find post 231 and 232.

#232 gives an idea of what and where the present cut-outs are. The actual cut outs now are even larger. The cut-outs reveal why the dodger ended up too heavy imco.
The molding you see is 3/4" thick on the stand-up face. What the cut-outs reveal is thicker epoxy/glass-matt laminations on the inside surface, 1/2" green divinylcell as the foam core, with a thinner glass layer on the outside face. The project was not vacuum-bagged.

The problem is that the substantial openings in the 'windscreen' are not molded and don't have molded in flanges. There is bothersome waste of expensive materials in the cut-outs.
This is one reason why I favor the same shape as this but done as wrap with simple plycore, single layer woven fiberglass on the surfaces. There is no need for a foam core windscreen on an Ariel. I just got drawn into the process. It was before you came in with your Blue Wrap Dodger CAD under yer arm!

Anyway, to how now to cut in the rabbets is the real problem? The curve of the screen is pretty extreme. The router I have is that onehorse Bosch trim with the tidy interchangable bases. The tilt base is actually a halfbase with a 3/4" wide slot that is open on the working side allowing the bit open access and visability to the work. Also have some D-handle PorterCable regular routers.

One method is to work on the piece directly with bits that have roller bearings.

Most rabbet bits cut only 1/2". I have a bit with a set of bearings that I think will allow a wider rabbet. But that isn't the real problem. Which is, according to my estimation, the need for a much wider rabbet, explained in a previous post.
I laid out windows for the widest openings possible imco. I'm right at the extremes of the windscreen. And I need a flange that is at least one inch wide, but I'd be much happier with 1 1/4".

To get that wide rabbet I'd make a pass to the correct depth with a regular rabbet bit. (Actually a three-wing slotting bit will do the job - without wasting the phenolic base for the oversized rabbet bit - attached outside the bottom of the base..) Then 'by hand' - following a trace line - carefully cut into the fiberglass making the full new width wanted with a Dremel 542/3 carbide cutting wheel*. Then, using the first router cut, take a utility knife and slice over to the fiberglass cut using the flat surface in the foam as a guide. The slice over will also, of course be through foam. Tedious.
Probably tedious to read too, Sorry.

The second method is to use a pattern with a bushing guide base on the P.C. and a straight bit. The Bosch trim router does not have this option.

The way out of course is to make a female hardboard routing pattern large enough to make the wide flange. Screw the pattern on to the windscreen. This is probably not possible on this windscreen because there is too little surface left to fasten the hardboard onto along the top and bottom of the windscreen where the holes already are. That option is no option. !#%$&*?! This would be my choice if possible.

I'll have to go with Tedious.
By the way, the best way to cut those wide flanges in a premolded foam composite like this windscreen...if you insist that this style and method is necessary...
is to layout all your parameters on the surface. Then DADO in the wide flange using female hardboard patterns. Then cut the openings out. The whole thing could be done with straight bits, including the cut-outs. I shoulda done it that way.
__________________________________________________ ________________________________________


But I did ask because these days it is possible I may have missed a tool or method I'm not aware of, or forgot!

Why is it getting into trouble so easy
and getting out so hard??
__________________________________________________ _________________________________________
The groove/channel in the hutch over the lazarette
that Tony mentions has photos at post 199 and 200...
It does make for a classy looking lid.

Can imagine sail-track in the bottom of the channel with a hinged two part lid on a couple sliders that will rise the lid up in the middle when pushed to open.
The lid is controlled and contained.
__________________________________________________ __________________________________________
*These are pricey 1"D scalloped thin circular metal plates coated in carbide grit on the end of a 1/8" shank. They work very well, but also get used up quick on hard work like cutting thru a couple layers of glass. They are not the small Dremel toothed saw blades on a shank which wear out even faster. Instantly.

[Steve M]

Hi ebb
saw the pictures 231 and 232 and understand your problem.
I don't have a ready answer nor could say "it will be easy" because even after cutting the fiberglass outer layer your moving into another problem or 2 and that is leveling the foams core and actually, successfully glassing into that little rebate.

May be heres an alternative that would ease the problem and 1/2 the time.

Consider 1. is the face surface nice and smooth or can it be made that way?
2. do a full wrap screen using 3/16 (4.5mm) lexan polycarbonate . It bends way better than plexiglass . this would sit on the surface not into a rebate but doesn't look bad really.
A full wrap piece once cut carefully and edge finished is really quite easy to work,it would have a smooth curve across the top and need a nicely radiused corner as you step down from the hatch box.
May be you could try a door skin ply template and it will offer similar resistance to the lexan.

I would cut a piece (of door skin) to fit neat across the box then leave the rest well oversize, pull it around and flat onto the dodger surface with ratchet straps to your dodger back edge or somwhere aft
When its really flat but not all dished in mark the openings from the inside onto doorskin , remove, lay flat and mark a nice neat top sweep that allows
you a 1"1/4 bedding surface.
test your completed pattern
This in turn will allow you to very simple rake back the core (1/2" )in your window openings , back fill them with bog , and finish with drum sander thing in a drill.
In fact I think you will not need to use any screws to retain the lexan Ill expound on this if this surface way is of interest to you.
One point to note if theres a lot of twist as well as bend to cover the surface then it gets more difficult how ever the only areas you ever need retaining on a smooth curved surface is the very ends your existing pillars will provide a resistance to dishing and a bonding surface.

Hope this want telling you how to suck eggs and might be a help.
I can direct you to a sight that makes and sells sealant and bedding and on there site has a good run down on the correct way to use a window bedding/glue which is imperative to this working
Steve Marshall

[ebb]

Steve,
thanks for continuing on this subject. Bending in or on the clear sheet is a problem that anyone doing a hard dodger can appreciate.

Your solution of bending on a single sheet of easy to bend thin stuff is a great way out of trouble. I will consider this.

I not sure what you mean by "rake back the core".
If you are saying that the single bent poly sheet can be inset - that also is a good idea IF..
IF, by 'raking out' the inset was easy to do.
I can see doing the rake out with a router on a long stiff base with the router moving on a sub-base back and forth over the surface to lower the surface into the core so that the plastic ends up flush within the surround.

That's too hard for me. Please understand though that the bend of the front of this windscreen is a dead FLAT curve with no twist. The doorskin pattern material would lay flat for side to side. And the plastic sheet would as well.


It's an esthetic problem for me to have thin sheet slabbed on top of such a THICK molding. I would be constantly bothered by looking at the edges. SO,
I'm going to figure something out to inset the lens separately. Also want the center lens to open, while the big sides are structural and fixed.
__________________________________________________ ______________________________________
Very interested in your NO FASTENING method of slab-on mounting of the clear sheet.
Maybe you use a series of clips - whose fasteners are attached to the dodger with stepped metal pieces over the edge of the lens? That's cool!

I would wet caulk a lens in place with a next generation silicone/polyurethane hybrid. If you look for the stuff, "green strength" single-tube syl-polymer can be found that will not squeeze-out like regular rubber caulk. The only hybrid caulk readily available in the USA is Life Seal. It does not have enouigh thickening in it (aka Green Strength) to resist squeeze out. Bostik makes a range of this hybrid and is sortof available through one marine catalog that I know about. Bostik's main claim is using this stuff for slab-on fake and real teak decking. It's said to be permanently flexible forever!

IF you are bending flat clear sheet onto a curved surface.

This might not be a huge problem on a dodger.
I have decided to slab-on Lexan to the Ariel cabin sides. The cabin sides are bent slightly. And I'm using 3/8" stuff. I'm also aware that any polycarbonate has to be replaced at some point, especially if it is going to be cooked in the Tropics.
I've found some nice sticky 1" wide butyl tape that has a fiber core. Using it in a non-rabbet slab-on situation is not smart I know - but I'm going to try it. The butyl should not be totally squeezed out if I'm careful loading the through fastenings. At least taking it apart again will be a breeze - as far as getting the goop off is concerned.

My plan for the wide rabbet in the dodger was to use the same stuff.

If you don't plan to ever remove the polycarbonate, there is another fabric tape called 'Everlast' (I think) - I have the roll down on the boat - that is nearly impossible to handle, but promises PERMANENTLY FLEXIBLE permanent bonding of dissimilar materials. That's wut they say!

Gotta run right now...
Steve... if you interested in this diversion, post some more...ok?

[Steve M]

Hi ebb In fact what I meant by raking out is simple digging out the core between the 2 layers of glass , that is inner layers and outer layers of fiberglass.
This can be done with a router but can also be easily accomplished by using a small round wire wheel in a drill. Its the sort that would be to big for a "dremmel" but suit an air grinder or drill. this makes a real neat job. This cavity you create is back filled with bog filler then sanded smooth with small drum sander in a drill.
Also by doing this (if you dig deep enough say 1/2") you are linking the inner and outer skins together.
Done right it creates a very neat edged opening in you core ( Ill take a photo of the boat windows Im doing and post)

To get to sealant Heres a sight to look at http://www.fixtech.com.au/index.php?id=212 It tells the correct way to install windows onto a surface and I think would alleviate all you concerns
I can tell you for a fact polyurethane or the correct silicon
( GE Silpruf SCS000 is good) applied and installed properly will require no fastenings other than for initial alignment and these would be place outside of the edge of your sheet and with large washers on
They would be removed after initial cure.
A webbing strap retaining pressure is reguired for several days.
Remember the actual pressure is a pulling back one and the very ends of your lexan panel are the ones trying to tear up wards, and away.
The rest of the panel in general is trying to move in sheer to the surface. As youll see in the site I mentioned the thickness of the bedding must be maintained for it to work as its got to absorb expansion and contraction of the lexan (same reason you use oversize holes)
http://www.fixtech.com.au/index.php?id=212 if this link doesn't work let me know
A dam tape is excellent and I try to use 1.5 mm this alleviates the need for "thick" silicon as the job of maintaining a space is done bythe tape also the difficult inside edge where silicon would normal squeeze out in big gobs is kept precise and neat( the edge of the carefully applied tape is all that is seen from inside the dodger) in an area of higher pressure say just about at the ends of your window, where most pressure will be exerted a very narrow second strip of dam tape can be added.
Steve Marshall

[ebb]

Have not yet identified a prefered dam tape here. But seems to be available from the auto suppliers.

But the tube stuff we are using IS the silicone modified polyurethane range that is similar to the Bostik range. There is no reason to believe it is the exact same stuff but EVERYbody is now making their version of it. I just looked.

Still, marketed world wide, it's not readily available to the DIY trade here. This is another reason why our home-grown omnificent WM is a PITA. They certainly seem to be AGAIN complicit in keeping superior products from the public while continuing to sell and catalog less versatile ones.
__________________________________________________ ________________________________________________
I've gone over the installation instructions on that goop site. Thanks for posting. I'm still confused as to the steps needed.

( I do understand that with a proper curing time you can get away with no fastenings at all!
Well, I don't know, I give my reasons for easy removal rather than convenient installation. Easy removal is a maintenance issue.)

I do detect in self some glimmer of comprehension in putting the window panels on with wet tube rubber - per instructions.
That is to prepare the opening with flat pellets or dots or darts of a material around the very OUTSIDE EDGE of the window, so that after we zigzag the goop in it will only squeeze out down as far as the limiting pieces. Small shapes of 1/8" EPDM sheet could be left in place. We could slice protruding tails off after the gasket cured. Better, put them in the middle of the flange surface and forget about 'em.
And then add 'a final bead of caulk around the window.' That's what I think the instructions say. BUT
I would hope that that wasn't necessary, as it would be a messy proposition.

I would guess that running a utility-knife carefully around the edge of the glass after the rubber has set to cut off the squeeze-out bulges would produce a clean look.

The purpose of the risers is to provide a rubber gasket line of continuous thickness. Could be any thickness that the installation data sheet recommends - whatever brand.

THAT is a good idea (even if I don't get the instructions). EPDM I will use because I have some plain non-foam 1/8" sheet. And the data sheets I have for the Bostik hybrid says the caulk likes to stick to EPDM. I'll do a dry run with the bolts to see if the epdm gets pressed thin from bending the polycarb into submission with fastenings.
Don't know that I will use the fancy goop. It might be, as you point out, an aggressive adhesive not requiring any fastenings, Too aggressive. I'm still thinking I'll go with old fashioned butyl tape. Has a good rep for staying soft for a good long time. Have to see about the limiting bits, ie what actual material to use with butyl tape.
AND if it don't fly we go to the miracle caulk.
__________________________________________________ __________________________________________

If we insist on using the sly-urethane hybrid goop:
Dam tape. How applied?
I understand it is used on the INSIDE of the dodger.
To which surface is it applied? If it is applied on the plastic window, as I believe, it is a narrow flexible tape that has to follow tight curves around the inside of the opening. It would be applied during the dry fit. It has to be thicker than the mini stand-ups used for the gasket.

Another kind of dam tape might be applied during the final dry fit to the FRAME. Not the window. It would create the inner dam by being slightly higher than the frame and just as high as the gasket needed. Unless this is very stiff material, installation pressure might billow rubber on to the glass.

A narrow foam tape, say 1/4" high, 1/2" wide, with a peel and stick surface would do the job. IF WE CAN KEEP IT IN PLACE.
The new fangled rubber hybrid rubber goop will stick to anything. And will certainly stick to the foam tape. It'll even stick to the white vinyl peeler strip we take off.
What I mean is, it don't seem like the dam tape will come off when the damn rubber caulk has gone off.
Is the dam tape there permanently on the inside of the window?
No way.

DEEP BREATH. Think I'll have an ale now!
This thread exchange is fantastic!
Hope I'm not being too stuupid.. Real sorry bout that.:rolleyes:

[Steve M]

Hi ebb
to answer your questions maybe out of order
dam tape is exactly what its suppose to be, that is a dam to stop sealant/ bedding flowing beyond where you want it to and totally saves clean up of excess.
Its purpose is two fold, not only to stop uncontrolled spread of sealant/bedding but to maintain a constant space between surface and glass.and thus a constant bedding thickness which stops the sealant shearing
The tape is available in a whole range of sizes generally from a glazier but Ill bet McMaster Carr has it. I use 1/8 thick x 3/8 wide. heres another place I just Google'd
http://corporateportal.ppg.com/NA/Glass/AutoGlass/300_Sundries/320_Catalog/cat_marcy.htm

It is stuck (it has one side sticky although you can get double sided) to the fiberglass dodger tight around the window openings and will very easily follow the curves you have provided you don't go wider than 3/8" (1/4" wide would work as well)
It is a closed cell tape and when the entire surface is considered it takes a heck of a lot to actually compress it flat.

I think the site I sent indicates putting a blackout coating onto the sanded and cleaned window edge. than applying the bulk of your sealant to the actual dodger rim that the window will press against.

If you were to do one full wrap window, then prior to any of this I would pull lexan all the way around into exactly the right position and be absolutely sure its laying flat on the dodger surface all round.

I would then drill 2 small holes top and bottom of the lexan screen right in the center.
these holes would take temporary locating pins (1/16 steel nails )
These would be for initial alignment, when placing the lexan.

With the window still pulled tight around the dodger and in the precise position, I would mark around it with pen then mask around on the outside,right up to this line.

When you then pull the window around for the final time with sealant on the dodger surface and a black out coat on the window edge, the dam tape will stop the sealant squeezing inwards and the excess will be squeezed out an onto your border of masking tape which also provides a guide as to placement .

Clean off any real big gobs that go over the tape on to the dodger but leave the rest and let the whole thing set and cure for several days.
The dam tape does remain in the job and provides a very neat finish edge on the inside of dodger, provided you put it on neatly and squarely to the edge.
The finish it leaves is far neater and way quicker than trying to clean up or true up black silicon that inverable goes everywhere.

This applies to a full wrap If you going for indevidual windows then you could do just the same but do the 2 side ones first then the center although if your going to make the center curved on open I just dont know what to suggest.

You would find that windows sealed/glued on like this, are in fact easer to remove than screwed and sealed windows.
Steve Marshall

[CapnK]

Sounds like this would be a good method for replacing the doghouse portlights as well! Once it's all set, I think I'd still use a few mechanical fasteners to make 'dam sure' that nothing gives way over time and stresses.

[ebb]

OK you gobs, did you ever think you'd get so educated on dodger building?

A few takes here. Brief!
McMasterCarr has a limited collection of foam tapes.
We are looking for GLAZING TAPE as the cross-over.
There are VHB (Very High Bond) tapes that are too thin. They are meant to glue things together: glass to glass, metal to metal, and maybe even polycarbonate to fiberglass laminate - but don't quote me on that! Glazing applications require good UV and heat resistance. Good rubber.

"Blackout" is a new term for me. It don't refer to WWII curtains. What it evidently means is a smooth, prepared, neutral surface that is the base for high-end aps like powder coating. Or, in case of our dodger. finishing off the edge of the cut-outs by making them fair, smooth and sound. That way the tape will have something to stick to.


It's going to take some research and phoning to find the dam tape or glazing tape. It can't stick TOO GOOD (like VHB), because it has to come off. It can't have an adhesive that will be left behind on the frame. The stickum has to be part of the foam tape. The product should mention that attribute. The foam in this use can be open cell.
I don't think that weather stripping or tape will do this job for us here.

Input on this very welcome!

My ap requires this stuff so I will find the stuff eventually........
And no doubt post a source.


:DSteve's method of registering the poly-wrap panel is a champion tip!!!
This is the kind of thing, coming from an expert, coming from experience, that blows all the other BS forums out of the water.

We got lucky.
:D

[ebb]

Marcy Tapes is the one.
Their tapes look excellent but they deal only with professionals and deal in cartons not rolls.
So far I've reached
only wholesalers in California.
So I will try some auto glass installers. Also used in the RV trade.
One guy said that 3M should have something -
Hardware stores have various weather tapes, most of them useless. You really want an OPEN CELL foam to allow air to get in and set up the goop. Somebody like Cabella's probably has it???

One wholesaler said he'd sell me a box of 12 (15') in a roll. of the stuff
Steve mentions......will keep on looking...
__________________________________________________ __________________________________________________ ____
NOTE on the FOLLOWING post by Steve M.

Thanks again for the tip.
The method described is obviously for clear sealant/adhesive. Although it would be perfect for black adhesive too.
True. The best look is when the flange appears to 'border' the window when viewing the finished job. And this method will help to minimize bubbles in the adhesive which are nearly unavoidable.
Jamestown hard catalog, only source I have found lists no clear Bostik sealant/adhesive.
Jamestown also does not appear to recognize that the 900 Bostik range is hybrid silicone/urethane. I would not order from them, just in case this stuff happens to be something else. Product descriptions have to be absolutely unambiguous. Clear, informative. Bostik makes the whole range of goops like all the manufacturers. Including clear silicone sealant which really should not be used for window installation.

BoatLife's LIFE SEAL adhesive/sealant - which IS a silicone/urethane hybrid DOES COME IN CLEAR.
However the stuff skins over faster than a speeding bullet. If you have prepared EVERYTHING before install including placating the seagods, you may get your polycarbonate on in time. I know I can't move that fast.

Using roll butyl tape means I can break for lunch in the middle of the job.
Have not heard any reason WHY NOT to use the stuff (except my roll is dark grey in color) ...... anybody???


DAM TAPE NOT FOUND YET!!!:(:(

[Steve M]

Black out is exactly That
By applying a thin evenly applied layer of black sealant to the bedding surface of your lexan which has been carefully masked off before hand you will get a very neat finish window installation.

The Easiest way to mask the surface (I'm referring to the inner window surface) is leave the protective brown paper or white plastic film in place.
Place the window in its position and have a means to register this position for precise repositioning.
While the window is in position, from the inside mark with pen around the perimeter of your opening this may be a bit wobbly due to ??

Anyhow remove the window and place on a table, inside face up
Now with a straight edge or suitable fairing batten mark out a new neat line with real nice neat radius and make this new line inboard of the actual marked line, say by about 2>3 mm.

Now, with a really sharp new razor, cut the paper or plastic protective film on the new straightened inner line and carefully remove the outer rim paper.

Note cut carefully all the way through the film so that you don't screw up the nice neat line when removing outer edge film.

Your sealant instructions may call for very light sanding of the newly exposed lexan and wiping with metho .nothing oily

When your totaly prepared to go and alls set, coat this exposed surface as mentioned above right up to and onto the still remaining center portion of film. make sure this coat is thin its only really to preform the job of (blackout) paint.
Keep any excess that goes onto the masking film to an absolute minimum.
the aim of all this is to provide a constant black appearance when viewed from the outside and a really neat inner finish line when looking through the window accompanied with using the thin black dam tape the job will look really neat.
dont try to pull tapes of to soon

Steve Marshall

[ebb]

Have IDed a candidate for use as a dam tape. A dam tape is applied around a window opening on the inside - before glazing - in such a fashion as to insure wet rubber from squeeze out doesn't get on the virgin plexi or polycarbonate. The idea is that when it is pulled after a generous set-up time we hopefully see a sharp clean window and jamb. The alternative is to scrape off the squeeze-out after bolting the window and clean the mess with a solvent. The scraping would scratch and the solvent screw up the $$$ plastic - and probably leave a cloud of #&^@(?<!! behind on the plastic. Have not found a ready supplier for the real Marcey tape that Steve Marshall mentions. Never seen the actual stuff, so it is difficult to search for a more available substitute.

Going to try a McMasterCarr polyethylene foam tape. [Page 3466, under Polyethylene Foam.] It comes in 1/8". 3/16" and 1/4" thickness. I got 1/4". Comes in widths from3/8" to 2". I got the 3/4".
It's cheap, white, pliable, lite weight, fine cell textured, and has a fairly aggressive stickum on one side. It seems FIRM enough to take the pressure of liquid rubber wanting to squeeze through IF the stickum holds onto the rabbet. If I do the black-out as Steve suggests and have a hard smooth surface the adhesive WILL stick good...Right? May still go with butyl tape. Which will not require the dam tape. Butyl is grey and I guess I'd have to do a Grey-out on the rabbets.

It's great that it is white so it will be easy to place on a dark window surround.** 50' on a big roll for $8.58 plus shipping. It would be ideal if it were open cell to allow air to pass through and help the caulk set-up. But it is closed cell. All peel and stick foam tapes found in the local hardware stores are too soft and smoochy for damming.

Ebb's the guinea-pig for rabbeted in windows - this time!
Soon to follow photo will show the windscreen has two large side lights that will have 1/4" lexan in rabbet, and an openable smaller center light also in a rebate. Will have to preform the plastic. First we'll try the cold bending over spacers method Steve described. Don't know that I can work with all that bending tension on the plastic with a lot of wet rubber - I'm not FAST and I'm not CLEAN - so I'm going to learn how to slump the lexan.
__________________________________________________ ____________________________________________
Our response here to Steve's sharing his hard dodger building methods with us may have helped him decide to produce what sounds like a DIY BOOK on the subject. See his blog. [Can someone post a blue-line here for it?]
I hope he goes into ALL of his dodger styles, and all of his methods. If I may say, he is a natural at it. his work is right-on and results beautiful. There is a crying need for such a book and I hope it is successful.

Steve has been active on his blog - there are some new pictures showing forms and jigs. And how clean he works!
Hope his book is brim full of stage by stage process pictures and or drawings!
THANKS, again!:cool:
__________________________________________________ ____________________________________________
__________________________________________________ ____________________________________________
*Could use this polyfoam tape as a dam for an epoxy project. Polyethylene (as in SeranWrap which literally blows off epoxy after it has set.) But a super hybrid goop that sticks almost anything together will, I predict, stick to the narrow edge of any tape that is against the caulk. And pieces of cheap foam will pull off. The tape has its skin sides top and bottom, so it will have a raw side dammed on the caulk. If I go wet I may take some MOLD RELEASE WAX and with a finger rub some on the interface of the foam. Maybe that'll work, maybe not?:p
__________________________________________________ ____________________________________________
**One proper way, one least prone to mess - and time consuming - is to do a complete dry fit - with all the window fastenings SNUG but not tight on the spacers. [It occurs to me that the spacers can be plain ole washers of choice and thickness - and if preglued to the rabbet over the holes (like with 5min epoxy) they'll be right where they need to be when applying the goop. I'll get some rubber ones from McMCarr.] Then using the glass as a guide slide on the dam tape, and press it firmly in place.
Undo the windows, lay just enough goop on the flange, c a r e f u l l y position the window in place (preformed of course), insert the bolts again, and tighten evenly and alternately (like tire nuts). Squeeze-out on the outside, if reasonable, might be left unmessedwith and sliced away later. The protective paper would still be on. Leave it shaved like that or finish off with a finger fillet of rubber or a bead. Neither will be easy.

Steve's single piece cold bent front sure sounds easy now!!!
imco as always

[CapnK]

Here's his blog:

http://marshalldesign.blogspot.com/

...but Mr Ebb, I'm not seeing the info there you refer to regarding a book...?

Someone in the harbor here built - while on a mooring - a hard dodger which looks a lot like what Tim has on "Che'". The boat itself is a Tahitian Ketch - full-on classic wooden gaffer. The forward line of his is a bit steep for my eye, but overall - and from a ways away - it looks good. I'm gonna try to get up close and more info (pics too) before he/they/she takes off...

[Tim D.]

I'm finishing up the electrical and moving of the propane tank right now (pictures and commentary in the "Che" section to follow soon), but have been thinking about the trimming of the inside of the dodger.

http://downloads.c-2.com/photos/1202178012.jpg

I plan on making wood trim for the portholes, but can't figure what to do around the windshield. Any ideas?

[ebb]

Howz doin Kurt?
Thanks for the blue line!

That page works if you keep scrolling on down to the kite-cad view of a dodger on a coach roof. There it's mentioned that he's 'working on a book'. I came in on that piece of the page through a google door that is titled: Marshall Design: Hard Dodgers for cruising sailboats. Custom..
But, going back that way just now I see April 2007 logged on the entry. So that means he's already on the book when he's visiting us. That, of course, is just FINE! ASSUME IS THE MOTHER OF ALL FOUL UPS.


Tim, Thanks for the cockpit view of the CHE shed-water dodger. Actually it's larger than what I imagined, close on like that. Still, big fools like me need a smidge more width here and a poke more height there. Looks useful and dry and didn't take a thousand hours to build either!
Wonder what you have in mind as trim for the dodger???

Find myself feeling great affection for very unadorned Ariels and Commanders.
Yet I seem to be committed to going the opposite way!

[ebb]

Just examined the Marshall Plan 'Hard Dodger Black-Out' tip again. Post #52

First thought is that if we are in a construction stage of building the dodger the black-out for the rabbet or the surround can be colored epoxy. If the color is mixed into thin laminating epoxy it can easily be painted on with a small brush.

When you are doing the final dry fit and have the plastic window with its protective covers still on and it's fitted and snug in place over the openings - why not carefully score the protective sheet using the edges of the opening inside as the guide. Probably an Xacto knife using a flat round tip blade to track easy.
Steve is saying to make the cut 1/64th of an inch inboard of the edge. Not sure why.

Like Steve says: after dry fit you take it apart, peel-off the edge ribbon of protective sheet and scuff the rim where you want the goop to stick. The sil-thane hybrid probably says you don't have to prep the surface. I'm still of the opinion that this installation doesn't need to be structural with everything bonded into a monocoque. The plastic lights will have to be replaced sooner or later down the line. Installing it onto a less aggressive caulk or tape might still keep the water out - or keep the water out WELL ENOUGH - and make it easier to take apart later. Call it a gasket.

The problem is: that 7 years later the tube caulk you used will be as hard as a rock. And replacement of the plastic windows will look like a federal case. So it IS a no-brainer that you choose the new hybrid (locally it's LifeSeal) which promises long life flexibility with excellent UV and ozone resistance. Problem is: it's also an excellent adhesive.
__________________________________________________ __________________________________________________ ________


Or see it as a maintenance issue and use butyl. The butyl tape readily available from Copperstate Roofing Supply
http://www.bestmaterials.com
comes in various but limited thicknesses and widths. I chose 3/32"X1" at $5.35/50' roll with a paper release - because my flanges are 1". It's gray.
Available from McMasterCarr, pg 3361, Butyl-Rubber Sealing Tape. Black and 1/8" thick and only comes in 1 1/2", 2 1/2", and 8" widths. The 1 1/2" is $22.74 for 48'. Too wide for most overlaps and flanges. However it's readily cut with a putty knife and a straight edge*. If you press down on the wstraight-edge when cutting you'll get a preview of its stickiness. Both tapes are tacky on both sides, very limp and conformable. Can tease the width of it around a radius. Have to cut it for corners, but you can smooch it together for a seal.
Doesn't smell nor come off on the hands. There is no interior core like some glazing tapes have, so you can pull it out of shape. The stuff is legendary for staying pliable, supposedly gets stronger the older it is, and has similar UV and ozone resist to the hybrid silthane. It is also conceivable that the material, having no core can squeeze out under fastening pressure and over time. Having equal torque on all the fastenings probably keeps it stable.

Don't know that anybody has reported what it's like taking butyl-taped glazing apart after seven years in the tropics. Have to assume though that it's going to be an easier job, than the hybrid or p.sulfide, prying the glazing off and scraping out the rabbet. It's a gum-like caulk not an adhesive. I'm also using it for the cabin windows. And thinking about putting the hatches and dodger on with the stuff.

*On a slab-on ap, where the windows are not in a rabbet, the too-wide tape could be used anyway and carefully trimmed with a new blade after it's all together? Might work same way with a rabbet installation by merely trimming the too-wide away inside with a knife after its done? It's clean stuff, the tape, no solvents. The putty knife is used to 'separate' squeeze-out from embedded stuff. Silicone coated kitchen implements can be used, if you find the shape you want.
The tape is very sticky but in a wad can be used to clean up a surface of butyl tape pieces and smears by pressing the wad on it.
Butyl tape with a strip of material inside the butyl can be found. I would not use this stuff if you are depending on squeeze-out to create your gasket. Cleanup would depend on cutting the embedded fabric - which would be hard to do because you can't really draw a sharp knife through butyl with success.

[McMasterCarr are the quickest but often not the cheapest! In talking to self here see clearly now that the way to go is with the 1/8" black stuff. And after the installation is complete trim off the excess. Think better in 1/8" rather than 3/32"!]
[WAY LATER EDIT: Control squeeze out of butyl tape by inserting a washer into the tape over each fastening before you put the fixture or lens on the cabin side or deck. The washer's thickness will prevent total squeeze-out when tightening up the window, plate, or base.]

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In the wet installation:
The foam rubber dam probably got glued to the tube supergoo. It MIGHT be persuaded by passing the same Xacto blade between the foam and the edge of the rabbet.

imco - no dam butyl ebb
"Go easy, if you can't go easy, go as easy as you can." radio sign-off by Jennifer Stone

[mbd]

This one looks pretty nice. Not sure about the aesthetics with our stepped dog house though...

http://www.sailnet.com/forums/gear-maintenance-articles/37194-hard-dodger.html

[ebb]

Mike, nice addition here.

Just for argument, the photo sez: Definitely homebuilt, DIY.
Nothing wrong with advertising homebuilt, Some designer pointed out that when making these additions the sight-line of the appendage should point to the stem fitting. They should tilt forward, if they are tall enough. I've noticed that this is good advice for hard dodgers that often make a boat look like it has a pilot house. Or extra cargo.

Soft dodgers which USUALLY don't confuse the boat's lines are often horizontal topped. But then the eye gets a discount when pram dodgers are a darker color than the boat. When in doubt, paint ANY dodger a darker color.

A hard dodger is the most difficult thing to add to a sailboat and make look acceptable. Some boats make it into the character stage where the skipper's personality tops the boat's and the amalgam is completely happy, or otherwise. Usually the color scheme is the give-away. There are boats that are too small or too large to obey this tradition.

Anyway, that the top of the dodger or any other large addition to the exposed deck/sheer of a boat, lines up with the deck at the bow, is a place to start from when designing something the critical eye will accept. Easy as drawing a line on the elevation plan to check it out.
imco It's a reasonable aesthetic that takes into account windage, greenwater and design. Streamlining tells a lot about a fish's lifestyle. Or a boat's, for that matter.
From that datum you makes your compromises.
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Downloaded an early '80s blackandwhite Cape Dory Yachts intro brochure listing all of their Alberg C.D.s.
Definitely designed to be a family of yachts, they each have features that every other has. Except maybe for the babys: the Typoon Daysailer and Weekender have the rounded rudder profile of the '60s A/Cs. The whole line sports the familiar full keel, soft cutaway forefoot and 'Constellation rudder'. (The babies might run aground alot - a round bottom rudder would be easy to get unstuck in mud, while a straight bottom constellator might be difficult to move.)
The no-doghouse coach roof in every case parallels the waterline emphasized with a trimline of teak over rectangular rounded portlights. Club foot jibs are featured. The larger yachts in the line are doubleheaded with short bowsprits.
None of Alberg's designs that I've noticed have shown even a hint of hard or soft dodger, or runabout wind-screen.
Maybe his later boats? I would have liked to see what the master would do with a dodger.