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Which is stronger

PostPosted: Tue Apr 07, 2015 4:18 pm
by Tim Ford
Which is stronger?

The application is: to keep my keel/keel foil in the boat, I am going to attach two strips of HDPE to the top of the foil. These two will rest on the top of the keel box/keel sleeve and hopefully keep the thing in the boat.

My worry is the integrity of the oak with the screws protruding either into it or completely through it. I'm worried that under frequent loading cycles, the oak will split parallel to the screws and the they''ll work out of the foil (even though the foil is physically constrained from expanding in X & Y dimension due to being wrapped in fiberglass, sunk in a carbon fiber sleeve/keelbox, and being pretty damn strong with which to begin.

My question is, which is least likely to result in the oak splitting at the top of the foil, A or B? (see crude drawing)

Which is stronger.jpg

Re: Which is stronger

PostPosted: Tue Apr 07, 2015 7:47 pm
by jray
As far as the oak splitting I don't know if one would be better the the other. Pre drill the strips, maby oversized, epoxy fill and drill again for the screws or bolts. The bolts probably have less chance of failure as time goes by then screws.

Just more work to do them then the screws. ;)

Re: Which is stronger

PostPosted: Tue Apr 07, 2015 10:14 pm
by ryderp
I would guess that through-bolts would be much more secure. I went with a top plate made out of stainless and CF, held to the keel using the Ikea method. I used 4" x 1/2" stainless bolts washers and nuts. I like this approach because it's easy to take the top plate off in order to remove the keel (which I had to do once). The top plate was also convenient for mounting a stainless U-bolt for lifting the keel.

Phil