A Hull Sheathing Alternative?

Being the one who said ply is not the best choice for the first strip of a cold moulded hull, I assume you meant me.

That statement was not fair or unfair, it was just fact.

A developable hull is in many cases better made in sheets of ply, and I agreed on that. (though not always, I do my hulls better in cold moulded, much better)
I know nothing about Kayaks, so cannot comment on your way of building them.

Regards
Richard

 

Reread Ruells coldmolding book, for 44' Terasa he began with 5/8" T&G longitudinally followed by two 3/8" ply strips diagonally cut 9.5" wide. With 52' Sarah he went 3/4" T&G with two 1/2" ply strips. The 3/4" T&G never caused undo stresses. He also mentioned preference for the ply and its related strengths compared to dimensional lumber.

 

Not just you Richard - however the others were just kidding it seems. I wasn't referring to kayak construction, but I am seeking better ways so my methods are currently under review ...

I tried to understand why a developable hull might be better cold-molded. The strips can be thinner so the resulting hull can be totally smooth with no chines; I can see that, also lighter with no laps, epoxy fillets or chine logs.

For a one off the cost and extra work of the mold is hard to justify and it's a more challenging method for an amateur builder like me. However for a pro building a production boat it's a different case.

 

We have no moulds, we make every single boat the same way a skilled homebuilder would do. Some temporarely framing is all.* Mostly destroyed after finishing. All boats I do in wood Ep, are one off and fully custom built.
Nearly 63% of the already sawn and cut timber we buy, ends up in the paper mill! Precious and rare Mahogany and Teak....

The reasons for cold moulding you already noticed. I can get a better fibre orientation and we have no laps/scarfs. On top of that we use the better quality veneers. It is by far the most expensive way of building boats, included carbon Epoxy composite.
By no means I would recommend it as the method of choice for a homebuild hard chine boat. It is just my way of producing quality, which nearly no one else can provide today. And the market proves me right.

*when you look at this picture, and imagine that the posts would be wooden and attached to the frames inside, you have a idea how we start the "mould" setup. Every frame has two posts going down to the floor. The keel and these posts hold the structure at starting the planking. Once the "shell" has sufficient stability, we replace the posts by moveable metal posts as in the picture, and plank the bottom. At the transom and at least the collision bulkhead the posts stay in place and are cut after the strips are applied and before the veneer goes on. They become part of the boat there.



Regards
Richard

ähh, our newer plants look a bit more tidy......

 

Timber ! Plywood ! Not the stuff I use. Mine is make of multi layer compressed cheese. Manchego outside skin for its aircured hardness and abilty to take Oregano and olive oil. Inside skins are cheedar and do a great job of stabalizing the sheet and providing long service life. And Gonzo, you might try some because the best part of this Plycheese is that I dont have to put Anodes in the bilge, simply a fresh coat of olive oil and a sprinkle of oregano from time to time. .

 

Not many here did expect anything else Michael. Your posts are full of cheese, and cheese only. Have a wine with it, relax, and leave. No one here has any advantage of your anecdotes, lies and bigmouth stories. The very few occasions where you could copy proper advice to look good, are not worth to mention......

bye
Richard

 

In the late 70's I raced a 35' IOR of triple diagonal construction. It was 12mm thick in Honduras mahogany with mahogany stringers and four plywood bulkhead for structure. The hull was epoxied but no fiberglass. I saw the boat last year, still in great shape.