Don't create a dissimilar metal circuit. If you
do, you'll just aggravate the corrosion problem,
especially in a salt water environment.
I don't recall the specifics of the problem;
however, I would bet that the fasteners (screws,
nuts and/or washers) were galvanically different
from what they were connecting, resulting in
corrosion. Pop riveting, as suggested by Tony
Brock-Fisher, may not be the best of ideas.
I recommend choosing similar metals for all
fasteners and tubing, or make sure that all parts
are electrically isolated to prevent a galvanic
couple. Then, seal all connections with
non-corrosive, non-conductive, outdoor silicone
(other resin bases could work as well) sealer.
This method will prevent an "on-site" and
"environmental" corrosion instigation.
There are quite a number of good (helpful and
informative to those who care; cure for insomniacs
for those that don't) books relating to metallic
corrosion. Most of them are not cheap (above $75)
and are written for undergraduate engineering
education level. Well worth the investment for
those buying/maintaining expensive metallic
things. I could provide information to those
73 de Pat, KA2GSL