Question:
I am pondering the purchase of a sailboat located in the Northeast, with
the usual freezing-induced foam-cored rudder delamination problems.
I'm pretty well aware of the standard repair technique, ie
splitting up the rudder shells and rebuilding the foam core.
There are some unanswered questions, though.
What is the best foam core material for constant underwater use?
Would balsa be better?
What about splitting the shells, clean them up, reseal them and then
inject foam? Any ideas about that technique and about which type of foam
should be used?
Also, any practicfal tricks on shaping the foam to reproduce rudder
shape? Is there an easy way of imitating the rudder shape, so
that the foam shape is close enough in shape so asto use minimum
epoxy when regluing inside halves? Or is it better to reshape
completely and then glue halves together?
Answer:
Practical Sailor did a great article about exactly that technique just a
short while ago. You might be able to get a reprint from them. It would be
worth it to get the article. Dan Spurr did the work (the editor). He
carefully split the shells (though a yard he spoke with used a Sawz-all),
cleaned them up, had a replacement stock built, glassed the ribs back to one
side of one shell, glued the other shell back on. He epoxied over the
leading edge with a few layers of glass. Then he poured in 2 part foam to
fill it. He used the above mentioned 8 lb/cu. ft two part foam instead of
the more common 2 lb./cu.ft. stuff. It cost him $1000 or so, but $800 of
that was to refabricate a new stock, that may not be required in your case.
