Forestay failure -Reply
Ted Dyer (TD7876@mail.gates.com)
Wed, 23 Sep 1998 09:32:28 -0600
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West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
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Just to start things off on forestay failure: (I hope to learn
something here): 1) The aircraft industry uses a rivet called a
Cherry Max that is a very high tensile item, just barely pullable
with a standard rivet gun. It is often backed with a washer. I'd be
willing to bet that these are the strongest pop rivets in existence.
Expect to use a numbered drill to create the hole. 2) Is stronger
always better? Many structures contain planned failure points.
Perhaps it is better to pull a rivet out than deform the mast or pull
a chainplate on the deck. Considering that your failure mode was
wear and not catastrophe, I think this is worth thinking about. 3)
Am I wrong in thinking that the forestay does not experience a lot of
tension under sail, but rather supports the jib and jib halyard as
they provide the bulk of the tension? That would mean the wire cable
construction is used, not for ultimate strength, but to simply
counter the fraying/stretching/size difficulties encountered where
line is used. Let the feeding begin.
Ted Dyer
P19 #1044
Penelope