Hard Dodgers

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.

Oops. Missed one

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'

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?

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 $$$.

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.

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.

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

http://forums.sailinganarchy.com/ind...howtopic=63965

Would come in handy sometimes

I've got something like this in mind

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 !!!

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?!?

: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!

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:

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?

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