Seems like both sides of this discussion have very valid points regarding the use of carbon in beams. Most of the considerations are regional, for example in Aus the aluminium supplier is monopolising the industry. If you want to use any extrusion other than round or square, you need a dye & minimum orders, which can make the alu. option costly. This problem is also experienced in South Africa. If we want to use round beams, we have to settle with a 76mm X 3mm wall thickness, as that is the only size that comes close to 80mm X 2mm, which would be lighter & more suitable. The Mozzie class is using 50x50x3mm square tubing as that`s all that is available that is close to the original specs. If we could use carbon in the beams we wouldn`t, I don`t think the performance gain (if there is one) would warrant the costs.
I don`t believe a boat with full carbon beams would have any performance advantage over a well-designed aluminium beam boat, as long as the beam to hull joints are well-designed. In my opinion the first part of the proposed rule is sufficient to keep the advantage to a minimum, and allay any fears of a "percieved" advantage of glued-in carbon beams. I`m making the assumption that carbon beams weigh the same as aluminium ones, based on previous posts, and the only gain is in stiffness. If the beams are not glued then part of this advantage goes away.
It`s been shown that a well-sailed Mozzie with a 10% speed disadvantage can get to the finish line ahead of Hobie Tigers, F16 Taipans etc that are not sailed to their potential, so a less-than-1% advantage in equipment is not going to determine the winner.
If we want to worry about carbon fibre in performance terms, I believe it will give much bigger returns in the hulls & more importantly the mast, as this determines sail shape characteristics. Since Carbon IS allowed in these areas, I would think it illogical to disallow it in the beams, especially given that in some areas it may actually be cheaper due to the difficulty of sourcing aluminium extrusions. By allowing carbon beams we should be able to source cost-effective solutions through the network of suppliers that are already involved in the class, as posters such as Darryl & Scott are implying. Perhaps a thorough investigation into these aspects should be done before we go to vote.
