Many thanks for the pics, some really interesting work and thought has gone into that build and the end result looks fantastic.....

Agree fully on the condensation issue, it's certainly a major part of the deck failure as we've all witnessed with TwiceShy's decks.
Any water in the hulls turns to a vapour and condensates on the highest point.. the decks... With the older build styles, the decks weren't sealed in any manor so the moisture attacked the timber decks from the inside, this in turn softened the ply and more importantly around the glassed areas where the foam supports sit, this then allows a small amount of movement of the deck / foam joint....
Once the decks move a little bit the foam is allowed to come under more load and slowly begins to compress under a sailors weight, the decks also move downwards which pushes the hull sides apart during this time, and that then places the strain on the foam to hull side connection, that's where the foam fails and the hull sides now move in and out slightly, this in-turn lets the decks come down even further crushing the foam even more as it goes and again the foam breaks it's contact with the hull sides further down....

It eventually gets to the point where nearly the entire foam / hull connection fails and the foam becomes nothing more than a loose piece of buoyancy hanging around in the hull...
With the foams having failed, the load then goes directly into the stringers and as they are now completely unsupported they now fail rather dramatically by cracking or splintering, once the decks have reached this stage the load then falls directly on the ply and it's life expectancy is very short.... The most noticeable thing at this stage is small splits in the paint work or small bulges in the ply specifically directly under where the beams are mounted.. So if you see a boat with a bulge or cracks in the paint work in that area there's a fair chance the decks are in need of attention.

During this whole process that condensation is working away at the foams and the timber and as each small fracture is opened that moisture makes it's way in further which speeds up the process even more.

With the ply support plates I do and the ones you've put in on top of the foams, the loads are spread out more evenly through the foam so the chance of a foam failure is minimal.

I'm really pleased with the lighter decks I have now, especially the fact that I can put my entire weight into the ball of my foot, stand on the decks and they don't move at all, with the 40gsm cloth glassed in on the underside of the ply the moisture has no starting point with which to start attacking the decks either, the up-side of the classed underside is the added strength for a very minimal weight addition.....

When I lay Scorpian's decks I'll also do a sample of the glassed ply and video it being loaded up, anyone that's seen me demonstrate this has been amazed as to how much strength is achieved....


In years to come others will find even better ways to do what we're doing and with even lighter and stronger materials..... I have so many different ideas I'd love to try out to get the fat off, maybe them old hulls might one day have a thread of their own...