naahhh - I'm with you. I'm being argumentative too but don't mean anything by it either.

Seriously though, if you're trying to measure the difference in stiffness of the plywood hulls vs. the composite glass hulls, why are you fooling with all the beams inbetween? That's what I meant about being scientific about "hull stiffness". You're measuring "platform stiffness" which has very little to do with the actual hull stiffness that we've been discussing. In other words, most of the platform movement you show in your measurements does not come from the hulls but instead from the beams and beam joint in between.

To 'scientifically' (I admit to using that term loosely - no lab coat required ) measure hull stiffness in the vertical axis, you would do something like support a hull under the bow and under the stern and place weight in the center - then measure the deflection there. A horizontal measurement would be a little more difficult with the boat assembled but I'm sure you see what I'm saying.

However, I am impressed with the platform stiffness of the Blade F18 compared to the other boats. While Phil may have not glued in the beams, I bet his beam socket was a bit more refined than what I had on my Nacra. I'll see if I can get a measurement on mine soon.



I thourghouly waxed the beams prior to joining them with the hulls hoping that that would aid in future removal if ever necessary. But I sanded the socket in the hulls, applied an epoxy slurry with microballons, put a bead of 3M 5200 around the perimeter, and snuggly bolted the beams in place. After allowing the epoxy to get to a 'firm but soft' state, I fully tightened the beams. The beam and hull union was NOT a good one from the factory - the socket in the hulls was not smooth and had bumps in it. While sailing, even after putting in as much 'grunt' as I dared to the bolts, I could see movement between the hull and beam while under sail. I sailed the boat before and after this operation and the difference was very noticable.

Of note - some weird reaction happened between the 5200 and the epoxy and where they both came out of the joint, the 5200 seemed to almost instantly cure. I probably wouldn't use them together like that again.