STRONGBACK DISCUSSION etc.

[Scott Galloway]

Ebb,

Thanks for the comments. I am definately in the restoration camp, but I am also in the "publish all approaches to commonly shared problems" camp. A multiplicity of approaches is what keeps this site interesting. Fortunately Ariel owners tend to stay that way for awhile, so we can all check back in later to see how some of these innovative ideas and retrofit solutions work and whether or not they hold up over time. I am eager to see your boat splash down. You have incorporated a number of innovative features in your Ariel. I look forward to reading about your sea trials, etc.

Peeks are easy. Just come down to Santa Cruz for a sail. As for photos of the repair, I referred above to my Ariel Structural retrofit page:

http://www.solopublications.com/sailarir.htm

There are photos aplenty there of this specific issue and other retrofit work I did in 2004. Most of what I did was restoration-oriented rather than redesign-oriented. One thing I didn't do that I would do if I had the mast off the boat again (and I am not eager to do that again) would be to put a tricolor LED light at the masthead. I didn't want the weight of a traditional tricolor light and weight of the requisite traditional wiring that high up the mast.

As to the hard work of building an integral void-less structural unit from my existing (undamaged) oak strong back, the deck, and the cabin liner beneath the mast step, the design and execution of that task was done under contract in my slip here in Santa Cruz by a professional who used vinyl ester resin and all sorts of modern glass fabric as described above to complete the job. So no polyester resin was used. Epoxy has its merits, and I have used it on other projects, but gelcoat doesn't stick to epoxy.

I was fortunate to have insurance coverage to cover the repair of the accident damage in this case and a skilled professional friend who was willing to take on the repair job on my little boat. This repair and new standing rigging were provided under contract. In the end I believe that my boat is now stronger than it was when it was built, and certainly it is stronger than it was before the accident. All other work on the restoration of my Ariel both in and out of water I did personally over the period 2001 to 2004.

And in the spirit of innovation, I have also documented my development of a sheet-to-tiller self-steering system for my Ariel on the following web page:

http://www.solopublications.com/sailariq.htm

That page, completed in 2005, has full documentation of the concept, design and execution with many photos of the self-steering gears working under sail. The design and application of the self steering gears on that page are based on the pioneering work of John Letcher as documented in his book, Self Steering for Sailing Craft International Marine Publishing Company, 1974; and some sketches and suggestions included in Tony Heisel's book, A Manual of Single Handed Sailing Arco Publishing Inc., 1981. I also relied heavily on the on-line resources including the pages produced by John Ward and Al Gunther.

I single hand a lot, and the Ariel Self-steering gears that I developed have greatly increased my range and endurance under sail. Certainly they have increased my enjoyment and comfort.

[ebb]

Scott,
By the way GELCOAT does stick to EPOXY.

The epoxy must be carefully measured and mixed. Must be fully cured. Must be NO BLUSH.
My specs would say: 100% solids - 1 to 1 or 1 to 2 parts premium epoxy, so that there is no solvent out gassing to mess with the polyester.
Then it should be sanded with 60 grit.

Gelcoat will stick to epoxy.
But why would you want to use gelcoat over perfectly good epoxy?

[Scott Galloway]

Well you must mix up a better batch of epoxy that I ever have. Also my recollection is that I have read in some marine publication that the bond between epoxy and gelcoat is not a secure one. Can't say that I recall where I read that exactly. The previous owner of my boat drilled a few holes and filled them with epoxy. Gelcoat stuck to that for awhile. I removed a spinnaker pole holder and filled those holes with epoxy as well and ditto for the failure of those bonds in time.

I mixed my batches of epoxy as per the West System's instructions. All of the epoxy that I have covered with gelcoat was cured and sanded before the application of the gelcoat, but I have no idea at this point what the ratio of resin to catalyst was, since that was a number of years ago. The epoxied areas were very small in relation to the areas to which I applied the gelcoat. If it works for you, that's cool, but my few experiences with gelcoat to epoxy bonds have not been 100% positive.

The reason that I use gelcoat is that my boat has, as did all Ariels, a gelcoat skin on top of the fiberglass deck molding. I applied a new coat of gelcoat in several areas where the original coat was worn or where holes had been drilled and filled, or where stress or impact cracks were evident. I like gelcoat. It's pretty stuff if you apply it correctly, and it looks and lasts better than LPU. As to epoxy being a safe product to use, the safety of all marine products in my opinion is a matter of mythology, unless of course you are applying steamed white rice to nori, in which case only the raw fish that you apply afterwards is potentially toxic.

[ebb]

It's a bit of a trick. When a polyester/glass boat gets laminated they spray gelcoat into the female mold and after partial set continue with the layers of glass and plastic. Can be said that the gelcoat in this case has a CHEMICAL bond with the laminate.

In the case of most repair, restoration, or new added work, gelcoat is the last layer. Most will distinguish this type of layering as MECHANICAL. And the gelcoat is going on as a coating. That's why a DIY looks for the most versatile product that is made for the job. I have heard that cured polyester can be 'softened' with styrene or acetone to help get a 'chemical' bond with a new polyester layer. That would include polyester gelcoat, I guess. Who wants to get into that!!??

We can think of ANY layer or coating as only achieving 'mechanical' bond - like a primer coat or finish paint. These days the most common and probably the best primer/sealers are epoxy based: single or two part, solvent or waterborne. A modern gelcoat product no doubt takes that into account. Paints and coatings can be almost any formulation these days including polyester. The epoxy undercoat usually sticks better and seals and neutralizes surfaces better.

Used on the exterior: gelcoat will protect UV sensitive epoxy. Gelcoat won't stick as good as epoxy, so prep is important.
These days every coating is modified one way or another: powder coating is done with modified polyester that produces good adhesion as a long lasting baked-on coating - usually on metal.

[carl291]

Sometimes I wonder if making one area super stiff (strong back area) is wise in a vessel that is constantly flexing and subject to so many outside forces.
My judgment is based on a tractor trailer truck that I had lenghtened the frame 30 " to install a larger sleeper. The frame rails cross members were C shaped steel, in my wisdom for improvement I used square tubing for extra support. This move stiffened the frame but after a period the truck suffered from cracked frame rails before and after the square cross members. After two attempts at repair that failed, I decided to go back and use the C shaped crossmembers, at this point I never had another frame fracture. What I learned from this was every componet has to work (move) together. Granted frame rails are parallell and the curvature of a hull and deck by nature spreads out a loading force
After 50 years of sailing, these boats are still floating, I don't thnk there has been any reports of a mast pushing through the deck on an Ariel or a Commander mast pushing through the keel.
I may be ignorant on boat construction but I would think short of total interior reconstruction (ie. Ebb) repairing water damage and worker screw ups and short cuts, the Alberg design is pretty sound, even when confronting bridges.
Hey, I'm just saying

[ebb]

Carl, this is a great point for discussion.
On boats I think naval architects and engineers are still out to lunch on the subject. Look at the constant breakdowns of the sleds in the Volvo Ocean Race and the repairs modern frp boats have to their hulls and decks.

I think FLEX came down to us from wooden boats, which are but bundles of mechanically connected pieces. Might say that the massively built clipper ships were very flexible - and while that may have saved them in heavy going - it may also have numbered their days.

I see the mighty oak vs the flexible sapling metaphor - but not sure how that relates to our A/Cs. Anything I propose comes from observation and reading, no formal training.

BUT, I think our boats have survived BECAUSE they were overbuilt and because they are STIFF.
We have exceptionally full and fair curves in the hull with no flats. The deck/cockpit mold also has curves in the flat appearing sections. As you know Ariels and Commanders have a pasted together BUTT JOINED DECK TO HULL SEAM. I don't know about other Pearson's of the time, but we might be the only class of boat that was put together this way. Lighter buillt engineered (chinsy) boats have serious problems with their hull to deck join - even if flanged, glued and screwed together.

And yet this seam which was pierced with screws from the s.s half round trim has never had an issue of actually coming apart. And I think that is because the boat AS A TORSION BEAM does not twist much. Given imco the seemingly casual way the bulkheads were put in this is pretty amazing.
I could be very wrong obviously. Somebody with a sailing Ariel can check this out by tying two lengths of string in an X from corner to corner in the cabin. If the tension is about even you might test any twist to the boat when close hauled by observing if one string or the other sags on a point sail.

Assuming this is a valid test, right? The boat might get more bent punching through heavy seas.


Because our four decade old boats began life in the beginning of the FIBERGLASS revolution Pearson got away with things modern boats have learned not to do. Engineers still push the envelope - usually for speed, and they don't ever think longevity.
While modern boats still manage to forget: stringers should never just stop but continue to the bow and stern. (Not done in the Ariel.)
Bulkheads (which are what helps keep a glass boat from twisting) should be attached to the hull and deck top-bottom-sides. (Not done in the Ariel.)
Bulkheads should not bear on the hull or deck without spreading the point load with wide fillets and tabbing. Thinner hulled modern boats float bulkheads
and attach them only from the sides - like a C-channel.

Carl, is your arguement that the funky way our boats were put together actually is the reason they lasted so long?

Even the A/C "over-built" hull showed the stress points. I know I found them when I faired the topsides prior to painting. The brown fairing compound in minor depressions on the old white gelcoat made a topo map of interior structures influencing the hull laminate.


I believe it is the nature of monocque construction to attain its integrity from having a stiff skin. Except maybe for ferro and steel the concept in fiberglass has its problems. Maybe a talented designer like C.A. takes that into account so that flex is factored into a plastic sailboat. The interior structure would take that into account.
But for the tabbing in of the accommodation settees and berths, I don't see that either the designer or manufacturer paid particular attention to hull-flex in my Ariel.

Ebb is certainly on record here concerning the support system under the mast.
I believe any flex here was due to corner-cutting and selling price. There cannot be flex here!

Don't know really to what extent the pros went to inside Scott's Ariel to tie the compression beam to the deck and to the bulkhead. In my mind's eye I see what I would have done. I believe the mast foundation should not move, ever. Any flex should certainly be in the rig. And setting up tensions in the rig would benefit hugely from an immovable base. We are talking about this single bulkhead. To spread the mast point load the cabin arch it stands on cannot be compromised. So arguably preserving that arch by almost any means is the right thing to do.


Now, Ebb, doing what he did: taking out most of this extremely important bearing and anti-torsion bulkhead, may be really asking for trouble. I'm depending on the overbuilt hull (which turns out in this later built hull, A338, is not so over-built) to stay out of trouble. Taking out the bulkhead and introducing FLEX could be my monkey. I'm tabbing in ALL my furniture, and call these panels: web frames. I feel that enough of them will nearly cancel out the torsion flex of the hull. Could be wrong. Like you say, Carl, trying to cancel out the natural flex of a fiberglass boat could be not only wrong but impossible.

On this score, I believe the lead ballast should be immobilized in the keel. That amount of weight concentrated in that one area in a relatively thin skinned vessel could out flex the innate stiffness of the monoque concept.


I've witnessed a couple earthquakes here in California.
I sat through one with a cup of tea in hand, actually enjoying the time of day and the landscape. I saw EVERYTHING in or on the landscape turn into waves: the solid ground, the porch I was sitting on, the house, the trees. Everything became plastic or liquid. Can't recall if the cup in my hand had the wave going through it.

Why couldn't a similar thing happen to a sailboat. Who's to say unknown vibrations can't happen to a vessel in water? So engineering gibberish and web frames will mean nothing when the boat turns to rubber. And it all becomes a wave form, including the skipper.

[carl291]

Carl, is your argument that the funky way our boats were put together actually is the reason they lasted so long?

I hadn't thought of it in that manner, but, yes to a degree. In my introductory work on 259, I find no part of the boat where the workmanship stands out as skilled joinery. The balsa under the mast step was a mistake but look how long that lasted! The cabin door is missing on 259 ,may have started to drag and was removed. When I check the squareness of the opening, it was still square.
Creating a super stiff section with no flex I don't think lessens the force, I would think it transfers the force and maybe even multiplys it to the weaker non-reinforced area, at least in the case of the truck frame.
Not having bulkheads fit perfectly to the hull and glued solidly helped to eliminate hard spots in the hull.
To look at any part of the construction of these great boats and say not done good enough really has been proved wrong by time. IMHO
Can you think of anything built in the 60's that has been used, abused and neglected and still be brought back to as good or better than new for less than the original purchase without adjusting for inflation?

[kendall]

I think a lot of the reason the doors are removed is because they make the interior feel smaller.
When I first looked at my triton, both doors were open and it felt pretty spacious, after cleaning it out enough to close the doors, it just seemed to feel a lot smaller.

198 doesn't have the door either, so I don't have any real experience. Though when I was working inside, I moved everything into the v-berth, and draped a sheet over the doorway, which made it feel much smaller.
What I'd like to do is open the doorway up a bit, which I feel would make it seem larger.
To do that though I think I'd have to go with a more robust strongback, and after having both my son in laws stand and bounce on the deck above the strongback,(400+lbs) with no detectable deformation, it seems sturdy enough that I don't want to mess with it just for cosmetics.


Ken.

[ebb]

Been trying to see some progress in the A338 interior. (hopefully some pics in the Gallery soon)
So the anti-compression beam/struts and old ply glued in some time ago came into focus again.
What remaining of the original ply bulkhead: the pieces across the top that match the section of the beam and the skinnied down struts that terminate on the V-berth with the skinny remains of old ply have finally been mechanically connected with 24 #14 s.s. phillipshead screws. These are 316 flathead sheetmetal screws - meaning that the shank of the screw is like a straight lag - not tapered like wood screws. These 1/4" screws are indeed lags. (McMasterCarr.)

Worked out great. Since I was screwing into oak the pilothole could be tweeked a little wider so that the fastening was driven (with the Hitachi hammer drill) without fear of breaking. I'm wondering what kind of sheetmetal these screws would normally be used for?
BTW, would never use 316 screws in an exposed situation. Only bronze or monel should be used in oak. Wet oak eats iron for breakfast.


As back up for the laminated oak beam I choose 3/8" silicon bronze carriage bolts (Jamestown) with the bolthead inside and the nut buried in the deck composite. Drilled in 7 of these bolts along the length.

Began with a 1/4" hole drilled completely through.
Used a 1 3/4" holesaw to cut through the top into the balsa. The little lid popped off easy enough exposing the dry tunafish.
A 1/2" chisel quickly (almost TOO easily!!!) evacuated the wood. Used the same chisel to undercut the surrounding balsa. Put a tiny chunk of 1/4" dowel in the hole.
Then dumped two-part epoxy into the holes. Gratified to see very little liquid get absorbed and mopped it out with papertowels.
Refilled the holes with mishmash and came back later with the little PorterCable beltsander and knocked the hockypucks flat.
Then redrill the 1/4" hole.
Took a Bosch 1 1/8" flat bit with a large screw pilot. This sort of thing will want to take charge and pull the bit into the work. But I was using the screw thingy to center the bit in the hole - and bored down into the new puck enough to take a washer and a jamnut - together only 1/4" in depth. Plus a skoch for the fill to cover.

I'm going down today to the boat where I will drill the hole out to 3/8". I think I will prepare the square recess in the oak, knock the bolt thru, screw on the nut and see if the Fein tool* can pare the end of the bolt off right on top of the nut.
I'll refill the remaining hole with mishmash. let it set (hope the epoxy makes up for the skinny nut), dish it out a bit with the grinder and top it with a little circle of 6oz glass.
Then fair. Should be relatively seamless and never show up in the future.

The main reason for the bolts is that I don't trust epoxy used to laminate the beam. The bolts are not parallel to each other as each was drilled in perpendicular to the curve of the beam. In itself that's pretty strong - even if fastening through the deck, as described, is questionable.

Seems like the structure is locked.
Pity the poor sap what has to take this apart in the future!
If there is ever any question about the beam, it certainly seems possible to add an aluminum plate to the V-berth side of the beam. The plate would be cut to the exact shape of the beam and the coachroof.. Since the load is at right angle to any fastening, they could copy the same 'sheetmetal' screw as above with the plate also glued on with rubber adhesive, isolating the screws as well.
Driving screws into the thin oak laminations, therefore keep the screws relatively short.
If I were doing this again I would cut the beam out of solid white oak like the original. Could vertically laminate together thinner planks and thru-bolt.

AND as FRANK DURANT sez the beam could be vertically cut out of MERANTI HYDROTEC BS-1088 sheet and glued together (TiteBond III?). Could be curve laminated also, I guess. Since solid oak has no short grain like the cross layers in ply, I would definitely make the cross section of a meranti glue-up heftier than the oak dimensions.
BTW, only this plywood - NO OTHER, NO FIR, NO BIRCH - can be used for this purpose. imco

Hope this is useful.
__________________________________________________ _________________________________________
*Fein tool not so fine. Did nothing on the bolt ends. You can take a Fein to metal, but you can't make it cut.
I got a rant on this tool we'll save for later. Put a little flex cutoff blade in the Makita grinder and cut the bronze bolt ends like it was banana.

[Commander 147]

I have been a woodworker for a long time and one of the magazines I like the best is Fine Woodworking. When I started doing my research for the correct glue to use on white oak I naturally went to Fine Woodworking to see what they had to say. Thought the article I found would possibly be of interest here so here is the link.

http://www.titebond.com/Download/pdf...urGlue_FWW.pdf

[ebb]

BUT FOR DISCUSSION let me throw in some things that imco have to be taken into account for woodwork on a boat.

NEVER USE AN "INTERIOR GLUE" ON A BOAT.

White Oak in lamination cannot be glued with any glue used in the Fine Woodworking test.
Titebond 3 so far as I know has not been tested for white oak bent laminations glued up under tension. Nor in a wet/dry cyclic boat environment.
I have HEARD for years that boatbuilders ("conventional wisdom") will not use any yellow glue because it will eventually creep because it is hygroscopic in the damp. The FW test is primarily for wood joints that will live in a fine moisture controlled frufru situation.
A glaring omission from the FW test is water resistant plastic resin glue you catalyzed with water. It has a long open time, requires clamping, and has almost no glue line. Commercial tillers use it.

Titebond 3 (not yellow but grey) seems to be a different animal, but will need testing for veneer laminations and other wood-to-wood gluing in damp.
The conventional test for glues used for wood-to-wood bonding is a four hour boil test!
There is only one glue that survives this test 100% and that is Resorcinol. This glue requires milled surfaces and pressure clamping, no gap filling, THAT I have always taken to mean very light sanding to deglaze surfaces.
Gorilla Glue has no place on a boat. I have witnessed a number of failures used for furniture. While epoxy is a glue, polyurethane* is not!

I have had my own failure with T-88, and wrote extensively here about my experience with it. My conclusion is that the best off the shelf 2-part STRUCTURAL EPOXY ("tropical wood") is made by Smith & Co.
I have used this glue for white oak laminations (untested) and noticed some starved joints. Imco it is very difficult to squeeze this product out of a clamped joint, BUT it seems to be possible and therefor is not used for bent in form lams.
I have some suggestions which have been reiterated elsewhere. Imco no trustworthy lamination can be made with ANY glue on white oak. Except Resorcinol.
And it may be that the oak must be pre-treated/de-natured to remove tannins.

I epoxy-laminated a white oak beam for A338. I put an epoxy saturated layer of fiberglass between each piece of oak in an attempt to not starve the joints. I also attempted to remove tannin oils with solvent and roughly scoured the faces with 40grit. Years now later I see some tiny separations appearing and decided to bolt the whole damn thing together - which I've described in the Gallery.
I'll always worry about it. Wood will ALWAYS move in a cyclic environment. In my case I have isolated the wood pieces with a hard non-moving material. Doesn't really work. So you see what happens using Resorcinol - there is NO glue joint. Can only describe the phenomenon as a chemical bond - rather than a secondary mechanical bond provided by ALL the other stickums.
WITHOUT QUESTION, it would be much better to bandsaw a new strongback out of solid white oak timber!!!

Ultimately, the best bond/attachment is always made with bolts and screws.
Maybe we should see glue as only in a support role for metal fastenings and as a caulk to keep moisture out of seams.

For wood-to-wood furniture work on the boat my gut feeling is that Titebond 3 can be used.
It is easy to use, there's no mixing, it's water cleanup, and hardly a glue line. Mahogany and fir and plywood, conventional joints like the open joints used in the FW test. Only an assumption.
Would like to see anecdotal evidence on this. [EG, what did Larry Pardey use for the extensive interior woodwork in Tallesin?]

For attaching wood to fiberglass there is also no 'boil test' guarantee that you will get bonding. Therefor fillets and tabbing must be used. And that has to be done with epoxy. Could say this method is an attempt to OVERPOWER the wood.
__________________________________________________ _______________________________
*Polyurethane tube rubber is another discussion.

[Ariel 109]

If a wood joint stood a chance of being exposed to constant dampness I don't think I would use anything but an epoxy or resorcinol, as much as I like Tite-Bond III. But cycling between wet and dry states will ultimately destroy any joint, regardless of the glue. We all know that maintaining the varnish or paint helps things last.

Resorcinol has a funny taste if I remember.

[ebb]

Resorcinol has the track record and is the only glue that will take extremes of wet and dry, heat and cold.
Epoxy has very limited exposure outside and has been known to disintegrate even if maintained. See the renovations that had to be done to all those traditional finished cruisers from 20/30 years ago - especially anchor platforms and bowsprits.
Epoxy glue is an interior glue! It can't take heat (it softens) and can't take cycling because it doesn't move. If you seriously have to keep exposed wood together, there's definitely 5200.

[Tony G]

So, er, uh, what are you guys sayin' here? My mast beam is going to fall apart? I haven't noticed anything coming undone voluntarily yet. Is 'yet' the operative word in the works here? Crimony! I guess Ebb's lead in holding the beam together is a fix I could apply easy enough, but, I'd rather think it wasn't necessary...crud. Oh well, one step forward and you know the rest.

[Ariel 109]

Resorcinol's rap is that of being harder to work with than epoxy. You can be sloppier with epoxy. Garden variety epoxies may have some trouble with UV and high temperatures but are tested as being stronger than resorcinol. And there are epoxies that perform well at higher temperatures. What are they making the new Boeing 787 from?

I agree that the best strong back is a band-sawed piece of solid white oak. Preferably from an old gnarly hanging tree.

Ben