I have used S/S and Monel (prefered) rivets in my boom and mast
sucessfully for over 20 years (in one cruising boat that spent a lot of time in warm waters). Tef Gel, Lanocote, Neverseze, and Locktite all worked well for me. I always use Mylar tape to insulate any fitting between the two surfaces. The "goop", regardless of which aforementioned variety was used, was liberally applied to the rivet before fastening.
I would make sure that dirt or dried salt
did not accumulate for long periods at the interface edges of the fittings and mast
or boom. As a result, there has been no visible sign of corrosion
. Often I drill and tap for 1/4 x 20 (would prefer a finer thread yet fine thread 1/4 inch fasteners are not always readily available) or 10 X 32 (way better than the usual 10 X 24) fasteners which are, of course, easy to remove and examine for any corrosion to the aluminum. I have never had difficulty removing such fasteners by using good sealant
(never silicone products) and ALWAYS have difficulty removing any fastener previously installed by others who did not use a good sealant
, even after only several months.
Remember that all aluminum is just "waiting" to return to its natural state: a white powder. Keeping other metals and chemicals away from aluminum surfaces helps ensure a metallic state. With good insulators and sealants you should have no trouble.