Canoe Ponderings by Red Rock Wilderness Store

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Grumman Canoe Repair

Q. I bought a used Grumman and there are two rivets missing in the front of the
canoe.  How is the best way to repair?
thanks Tom

Sub. A. Hello Joe,   These rivets are on the bottom of the canoe, so naturally they
are under the water line.  I stopped by a marine store today and they have
an aluminum caulk, it would seam practical to me to use a combination of new
rivets (or flat head bolts/washers) and the aluminum caulk.  The rivets are
under the front cover so even if the bolts and washer protruded slightly I
don't think it would cause a problem.  Tom

A. Tom-
It's pretty hard to answer your question.  Are they above/below the
waterline?  What do they appear to be holding together?
We once had a customer who came in asking for a "wingnut for a french road
bike" - couldn't tell him too much either but that phrase is going down in
history here.

I'll wait to hear form you.

I'd probably go with the bolts, compression nuts (the kind with the nylon insert built in) and maybe that aluminum caulk, although 100% silicon under the bolt heads and then over the nuts inside will do the trick very well.  Use a small wire brush to srcub the aluminum shiny wherever the caulk will be applied.  It'll really stick well.
Your other option is to get two solid aluminum rivets that fit the wholes and protrude into the canoe about 1/8 of an inch or so.  Then, if you can get at it from both sides or even with a partner on the inside, hold a regular hammer head (actually grab the hammer with hand, not by handle and push against the round side of the rivet from the outside of the canoe and tap on the rivet sticking in the canoe with alternating hardness hits "tap TAP, tap TAP, tap TAP, tap TAP, etc.  This causes the rivet to mush down and expand into the rivet hole.  The kee is to keep a hanmer face pushed up against the rivet from the outside, otherwise it won't work.  If you are unsuccessful with this you can always drill the rivet out with a hand drill, try again or go to the bolt.  First see if you can get the rivets at the marine store.  Cost about 25 cents each.

One final quick fix would be to get sheet metal screws that have a shaft size of the hole or close to it but not bigger (not thread size - look between the threads at the shaft), apply some silcone to the underside of the screwhead, and screw in place.  Again make sure that the aluminum has been shined with coarse steel wool or wire brush.  Sometimes screws like this last for years and years.  You could always replace them with bolts but then you have to remove the air-tank cover.  Try it and see what happens.

Hope this is helpful.  Merry Christmas!

Joe
Red Rock