J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Too Many Holes

Ok, here is another way to look at it. I just went out to the shop and found 1/4" 20 carriage head bolts drilled through the Cousa and some new balsa I had (I have no idea what grade it is, other than it appears very similar to all the other balsa I have seen in my boat) and got the good torque wrench I have out. The Cousa almost got to 10 ft. lbs. (the lowest level this wrench can do) before the carriage head started to pull through the material. The balsa on the other hand didn't come anywhere close to tripping the wrench before the carriage head was pulling through. If the surface area under the carriage head were larger for sure the torque or compressive values would have gone higher for both material tests, but the results would still have favored the Cousa board.

What this crazy simple test doesn't tell you anything about is what the compressive strength of either material would be with the same amount of added FRP on both surfaces and with a proper sized washer to spread the load out on both surfaces. But if the bare material has higher compressive strength, then it would seem reasonable to me that with the same amount of added glass on both samples the results would still be essentially the same with just higher numbers.

I am not an engeneer either, just a hands on kind of guy.