Cold Moulded Boats Illustrated Guide

[Steadman Uhlich]

I came across this photo while surfing for something else, and copied it for later ID. I am pretty sure this is an ATALANTA cockpit. No positive ID, on the photo.

[mitiempo]

Originally Posted by UNCIVILIZED

I'm surprised that on one's put Endangered Species into this thread yet. She's definitely a pretty one, & is old school cold molded. Rather well known to, thanks to who built her.

Agreed. Here she is with designer/owner/builder John Guzzwell at the helm:

[UNCIVILIZED]

Originally Posted by mitiempo

Agreed. Here she is with designer/owner/builder John Guzzwell at the helm:

The article about building her is Definitely worth the read (in a back issue of Wooden Boat I think). Not only do you get quite the education into both how boats are built, & cold molded construction. But into the why behind her also. Plus on what goes into much of boats' basic systems, including some on rig building for example.
She's quite the gem to see in person too, not to mention how she sails.

[Smokeys Kitchen]

I'm surprised no one has mentioned Van Dam Boatworks in the thread yet. I used to read Wooden Boat for several years and would just look at their boats and drool. I don't know how many practitioners of the cold molding art still do it on this scale, but they turn out some real beauties; both sail and power.

Van Dam - Custom Wooden Boat Builders and Designers

[Rough Magic]

Great thread. Two summers ago I had the pleasure of taking a class at the Wooden Boat School in Brooklin ME. We built a 'Tom Cat', designed by William Garden. 1/8 inch Spanish cedar, three layers, lots of staples. The staples at the keel and the sheer were fiberglass composite and were left in the boat. Strong, light, rigid. Some day I plan on building one in my garage. Someday.

[SailingFan]

Originally Posted by boatman61

Don't know if this is of interest to the Thread.. it used cold moulding techniques combined with a hot glue and vacuum process to make near 100% rot proof decks and hulls.. the idea was to let gravity create an even compression.
The photo is of a Fairey Atalanta.. examples are still going strong today in the UK.. its a no middle way boat.. you either love it or hate it..

Construction methods[edit]
The hot moulding process was an adaptation to post war boat building of the method originally developed by de Havillands in the 1930s for "stressed skin" wooden aircraft production, using layers of thin birch plywood sandwiched together with glue over a male mould and "cooked" in a large oven called an “autoclave” By using true mass-production techniques, Fairey Marine were able to turn out vast numbers of identical boats at an unprecedented quality and price. Moulds were constructed from spruce, built up on a steel base plate. Seven by three inches planks cut to the waterplane sections provided the starting point. Working from the sheerline, the planks were built up in a series of steps, arriving quickly at a close representation of the designed shape. Subsequent fairing yielded finished dimensions. Rebates for the keel, stem and transom completed the mould building process. Although the veneers used to produce Fairey boats may appear to be parallel sided, every one was in fact profiled. Rather than shaping each veneer to fit on the mould, as in traditional boat building, Faireys saved an enormous amount of time by sawing complete sets of veneers to precision patterns. Veneers were produced in stacks of six. Boat were then typically built in batches of 24 or 36. Early boats used 1/8″ spruce ply, surplus to the War Department’s de Havilland Mosquito aircraft programme. When this material became unavailable it was replaced by 2.5*mm agba veneers.
Chosen for its high gum content, agba formed easily without splitting and glued well. All the dinghy classes used just three agba veneers while some of the bigger boats used up to six. Initially all the veneers were laid at 45° while later boats changed to fore and aft outer planking for aesthetic reasons. With the keel, stem and transom in place, veneers were applied starting on the centreline and working out towards the shear. Each veneer was held in place by just three staples at the keel, bilge and shearline. Roller-application of Borden One-Shot waterproof glue preceded each veneer except the first. With all veneers in place a vacuum bag was drawn over the moulding and secured in place using a clamp plate and G-clamps. Early vacuum bags were made from war surplus barrage balloon fabric. After about 1950, individual rubber bags were prepared on the moulds using uncured rubber sheets which were subsequently vulcanised in the autoclaves used for production.[6]
Placed in the autoclave, the vacuum was drawn down to 27/28*inches water-gauge and steam at a pressure of some 50 pounds per square inch introduced. Processing took about 45 minutes at 100*°C. Curing at elevated temperatures under vacuum not only ensured that all the veneers were firmly consolidated – a process requiring many thousands of staples using the conventional cold-moulding process – but allowed for the use of a truly waterproof, single part, high-temperature curing glue. During the curing process the glue impregnated the wood resulting in a virtually rot-proof finished shell. Components such as side-decks were also hot moulded while other parts required for assembly were cut to patterns in the same way as the skin veneers. For one of the more complex boats, the International 14, the time for final construction from bare hull to finished boat was set at 230-man-hours compared to 400–500 hours associated with traditional construction.

That vessel photo is reminiscent of the barrelback boats I have seen used as Captain's launches in the US Navy, but with a sail instead of only engines. I agree with you, I fall in the "don't like" category from the aesthetic point of view, but hey, if it will stay afloat in a storm, I'll take one!

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[Steadman Uhlich]

Originally Posted by Rough Magic

Great thread. Two summers ago I had the pleasure of taking a class at the Wooden Boat School in Brooklin ME. We built a 'Tom Cat', designed by William Garden. 1/8 inch Spanish cedar, three layers, lots of staples. The staples at the keel and the sheer were fiberglass composite and were left in the boat. Strong, light, rigid. Some day I plan on building one in my garage. Someday.

Thanks for posting that mention of the materials and the staple material especially. Post a photo if you have some.

[dberdou]

Originally Posted by smj

Yes that is cold molded. Our cat is 4 layers of 1/8" oukume ply on diagonal vacuum bagged with epoxy. What design cat do you own?


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Hello
Thank you for the information!
The architect is Dominique Presles. I attached a photo
I will post photos of repairs as i get them
What type of catamaran is yours, who designed it?
Hope to see your post soon
Regards

[Delancey]

Originally Posted by Steady Hand

Thanks for posting that mention of the materials and the staple material especially. Post a photo if you have some.

Monel staples can be used also. They are expensive and hard to find though.

I have had good experience stapling through plastic strapping used for packaging. After the epoxy had cured pull off the strapping and the staples come with it. Staple holes get filled with the next coat of epoxy.

[UNCIVILIZED]

Originally Posted by Delancey

Monel staples can be used also. They are expensive and hard to find though. I have had good experience stapling through plastic strapping used for packaging. After the epoxy had cured pull off the strapping and the staples come with it. Staple holes get filled with the next coat of epoxy.

Good tip! Do you also own a set of "Parrot's Beak" pliers? The one's described in On Boat Construction (IIRC). I love any excuse to make lots of sparks by shaping metal on a bench top sander/grinder. The 12yr old in me lives !!!

[Delancey]

I have seen the parrot's beaks pliers before but never had one.

The strapping trick works pretty good and the strapping itself is pretty cheap. Nice beacuse the plastic does not bond with epoxy. Sometimes, depending on your staple placement preciscion or lack thereof, when you pull the strapping it will split down the length in the middle leaving a row of staples with one leg of the staples still in the wood. Then have to revert to pliers to get them out the rest of the way but not the end of the world.

[Delancey]

So back when I had a shop and was doing some boatbuilding I found a lumber yard / sawmill nearby where all they did was receive large Western Red Cedar timbers which they would resaw into smaller sizes mostly for commercial applications. Just so happens they had a huge dumpster full of drop material.

I made myself friendly with the bandsaw guy and ended up carting away van loads of the drop material in trade for a case of beer per load. Saved them on dumpster costs and in return I got thousands and thousands of of linear feet of 3/8" to 1/4" thick by up to 12" wide roughsawn planks which yielded mostly clear 1/8" thick 6" to 8" wide veneer. Most of it vertical grain. Gave my planer quite a workout but beautiful stuff. Perfect for boatbuilding!!!

I am in a different part of the country now and just happened to drive past a similar outfit. Anyone considering a cold molded boatbuilding project would do well to seek out one of these places since I have a feeling they must be here and there and everywhere there is a need for large dimension WRC. Otherwise this beautiful material is just going into the landfill.

Try searching google maps for "cedar lumber" and/or "sawmill" in your area.

[smj]

Originally Posted by dberdou

Hello

Thank you for the information!

The architect is Dominique Presles. I attached a photo

I will post photos of repairs as i get them

What type of catamaran is yours, who designed it?

Hope to see your post soon

Regards

That's one nice looking catamaran. Where is she located?
Our cat is a John Marples designed Searunner 36HT that was stretched by the original builder to 38'. We bought her pretty much as a sailable shell, and have done enough work on her in the last 2 months to make her comfortable enough to move south for the winter. Much work still left to do!


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[foufou]

At the same period that "hot" molding was going on there were cold molding glues in use that produced good hulls if carefully used. They were resorcinol, aerolite, and sometimes weldwood. These glues did not have gap filling properties of epoxy but were high strength. I have owned and built small cold molded boats and can attest to their strength, stiffness and durability

[JJ77]

Nice blog about a wooden schooner built in the UK this year;
sywolfhound


designed by Olivier van Meer,built by MB Yachts Ltd.





pretty