Well I did warn you that building the hull halves is the easiest bit and probably the least time consuming. We have now built both halves by taking the first half out of the formers and by rotating the formers 180 degrees, but leaving them at the same end of the hardback, you get the opposite half. Sounds odd but it works and now having matched the two halves, works remarkably well.
Lessons learnt from these two halves, do use a cutting screw to go through and on into the foam to locate the foam, its fast. Do use lots of heat to fair the foam into bends. Do try and get full length foam panels, we ended up with a join in the foam along the length, these are the one areas which are going to give us fairing problems with the vertical joins really fitting flat and fair. Do use Gorilla glue to join the strips as you go, but do use sparingly as it foams up probably 4 times its original volume and I do worry that it may grip the Gaffa tape on the wooden stringers better than expected. Do make sure you remove all the location screws, if you do catch your hand on any protruding through the stringer, whilst removing the hull from the formers and stringers, the tips are cutting edges and skin and hands are no contest ( as I discovered really deeply cutting the palm of my hand ) Do consider buying 45/45 cloth for the inner hull carbon, its more expensive than the cloth we purchased at £ 10.00 per metre but you get a straight length ways run which is far easier than trying to join and maintaining a 45 degree patten by going across the hull. Time costs.
So what do you with the first half whilst building the second ? We had a logistic problem of having two support poles in the middle of the workshop. Inconveniently positioned as to not let us move the 1st half to the other side of the workshop. To solve this we cut the hull into two halves at the rear cabin bulkhead separating the cabin and cockpit areas. Its not a bad call to do this anyway as its a relatively easy repair at this stage once the two halves are joined, but for us working both single handed and with two sometimes, the halves are easy to manoeuvre and lift without breaking the hull anyway at the cabin and cockpit intersection,as its quite vulnerable there. Do construct some width and height retainers to keep the shape as best as possible as the shape will change over time if not constrained. We simply used a piece of batten screwed straight through the foam and cloth with a small block either side to spread any load. It worked and when we put the two halves together they still fitted well.
So what now, well here comes some truly time consuming bits and pieces, like all the bulkheads, front prodder pole, front forestay tang among other jobs such as sanding back all the rough overlaps of cloth whilst the hulls are easily acessed.
OK the bulkheads are a real pain but needed, they are seriously time consuming and you feel you are getting nowhere but remember the whole structural integrity of the boat depends on these as they take all the loadings from the floats and rig, in some cases there are many tonnes of load at certain points if the boat starts to lift the central hull under full sail. The most time consuming we found was the central bulkhead which is set out as an engineered ring style bulkhead. It has a complex set up of layers and attachment points, I do feel it is over engineered but this bulkhead has been professionally designed by an engineering company in New Zealand which did a lot of the team NZ America’s Cup structural engineering. At 4.8kgs its a lot of carbon in a relatively small area and I hope once we can get the first boat on the water, we can revise this bulkhead to be a bit more light weight. It took me 4 days to just make the pattern, the former, the foam layers and then the two sides. To make the ½ moon water stay attachment points is 60 layers of glass taking 4 hours or so for both back and front beam bulkheads. In fairness it will save a lot of time and expense this way and all the the excess pieces not used in the half moons, make great hard points in the hull for the likes of the forestay tang and any mounting points needed.
Front Beam Bulkhead former with foam and stay mounts.
Bulkheads in place ready for the final pairing of the hulls
Bow and prodder tube detail with glass “ square “ for the trailer winch point and or prodder support wire. Note the small additional layers tapered to spread the load.
Note the additional flat area in the water line area and along the bow edge, its to bond the two halves together as you cannot get in there once the hull halves are joined.
Front forestay tang, could be smaller but I wanted an additional area for an anchoring eye and for the spinny retrieve system rope tails ( 2:1 out haul ) The tube is a carbon windsurf mast that has been broken and free at the bottom of the boat park. Once trimmed down to size it will be about 2/3rds the length in the photo. I also cut quite a bit of the glass area away and inserted a ½ moon of carbon and foam to lighten it.
Hulls now together and showing the true shape, a very pleasing almost a “skiff on steroids with a small cabin” style. Ignore the rear transom cutout shape, it will be much more sloped than shown.
Note the join line in the foam, a real no no as it has left quite a hard join. Solvable with a bit of sanding but we need to take care not to thin the foam too much. There is an extra layer of Kevlar which goes above this point so strength is not an issue. On the other half we have moved the join up to the more flat area closer to the strake and staggered the join. It works much better but still I would advise to try and keep a full length strip, as the vertical joins are really flat and fair.