~Roy~ wrote:

Find an airport and pay a visit to the local repair parts facility and
buy some aircraft grade rivets.

Do NOT do this! -- or not unless you can be very sure of the exact
content of the alloy used in the rivets. Alloys used in aircraft
construction tend to have a high copper content, and a mix of copper
and aluminum is the very last thing you want in salt water.

A lot of aircraft aluminum was used in boat construction when
aluminum boats first came into wide production, and this has led to a
lasting prejudice against alloy hulls. They just corroded all to
pieces, way too fast. There's a good chance that this is the problem
with the original rivets in the 1973 hull to begin with. It wasn't
until later on that builders (and insurers) came to understand just
how quickly the wrong aluminum can disintegrate in salt water.

Don't discount aircraft stuff out of hand; but be sure that it's not
full of copper before you use it. If the supplier can't verify that,
run away.

Pete

--
Artful Bodger
http://www.artfulbodger.net