Hull shell

I started with the deck panel (55cm by 2.4m) to test the vacuum bag and layed up carbon on the inside of the foam. This went Ok so I had the confidance to do all the other panels (1.15m by 3.6m) in one hit. You need a big table for this and so I used the top of my frame structure. Once I had my hull panels with there inside skin of 200g carbon I fixed them to the frames with double sided sticky tape.

The topsides aft have rather an aggressive twist which causes the panels to buckle. The computer modeled panels shear but real panels do not.

The topsides can either buckle out or in. I have removed the frame one in from the transom and allowed the topsides to buckle in. This makes a step towards a WSH (http://www.culnane.net/dc/sailing/moth/wshpaper/wshlines.htm) type stern which may be a good idea. It certainly gives the boat a even more radical look.

The twist on the forward panels does not have the same problem as the aft panels because they are not as wide and the twist id more progressive.

There is however room for development of deign here for future iterations, but I am happy with the result at the moment.

The hull panels have the inter carbon skin laminated on to 5mm foam. They are very flimsy but the frame spacing is just close enough to work. The cutting and shaping of the panels is more like model making than traditional boat building as the materials are so light and delicate. More time could be invested in placing stringers along the frames to support these panels better.

The inner skin could maybe be 160g carbon rather than 200 gram. This would save a little weight.

I weighted the flat panel and calculated a weight per square meter at about 1.2 kg. (aprox. 400g carbon + 350g foam + 450g resin) This is not as good as the pre-preg autoclaved Prowlers which are about that with paint. I will save weight by making the boat smaller and not putting much paint on, but I will need some filler because do not have a female mold. Some may say that this is disappointing and to have a competitive boat you need the latest technology. However sailing skill and set up are more important than the latest boat building technology. So from a pragmatic view I am delighted with the fact that I am in the right ball park.

I used the cut and fold technique to make the fordeck. The cut bit involves cutting a strip of the inside carbon out with a knife and cutting a V shape in the foam.

then you fold.

Some bog in the V shape and later a bit of tape you get a nice radius on the outside, and the join is only on the inside so it does not need finishing.

There are 2 bulkheads and a transom fitted to the shell. The bulkhead under the Mast is water tight to satisfy the 2 compartment requirement. The one at the main foil has a drainage hole at the bottom.

The bulkheads are filleted and taped in.