One of the curses of aluminum boats is corrosion where the railing posts are screwed to the deck.
In the first photo the railing has been removed to reveal the usual mess below it. (The deck in this particular location had the usual "minor" paint blisters showing, and black crud had built up below the rubber gasket.) In the next photo the mess has been sanded down to bare metal. Note that corrosion is halfway through the deck in one spot! This was the worse case, but every post had some level of corrosion growing under it.
In the next photo the mess has been sanded down to bare metal. Note that corrosion is halfway through the deck in one spot! This was the worse case, but every post had some level of corrosion growing under it.
In the next photo, the aluminum step plate has been removed. Note that, though there is a bit of corrosion near one of the screws, and some black crud hiding below it, there was none of the deep, ugly corrosion found under the railing posts. My conclusion: Those rubber gaskets are bad news!
In the next photo, I'm installing aluminum rivets in 17/64 inch drilled holes. The homemade rivet setter in the left photo works great if there's room to swing the handle. When there isn't, a ratchet and grade 8 bolt and nuts have to do. Get several for they wear out.
In the last photo the aluminum rivets have been 'set' and 1/8 “ thick plastic washers are glued on top of them with silicone (since the washers are tough to locate under the posts unless they are glued in place.) A rubber gasket is NOT used, to prevent moisture trapped below the gasket setting up a corrosion cell.
The rivet nuts came from McMaster-Carr part # 94020A323. Very nice people to deal with!
Washers (#8 polyethylene): McMaster-Carr # 95649A225
Stainless FH #8-32 x ¾ “ bolts (for assembly): McMaster-Carr # 91500A197
Installation bolts are # 8 - 32 Allen with matching grade 8 nuts Buy DOZENS of both--you'll need 'em!
Homemade Rivet Tool
Study the right photo. That small piece of metal (4 x 2 inch) with a hole drilled in one end is the "handle". The Allen bolt goes into a nut, then through the "handle", then into the Rivet Nut.Place the Rivet Nut, handle and bolt assembly in the hole in the deck, hold onto the "handle" so it won't turn and tighten the nut (on the Allen bolt. Sometimes you'll need to also have to stop the Allen bolt from turning until the Rivet Nut starts to seat.)
The drawing below the photo is of a homemade installation tool. Hold the 'static' piece, to keep the rivet from rotating, and put about two turns on the rivet with the "nut" (that doesn't strip like a hex nut). A socket head allen bolt is the only high strength bolt I could find in this small size. A regular nut and bolt strips way too easily. Oh, better buy several of each for they wear out quickly.
Note: You can also buy a rivet gun with adapters to set the rivets. I honestly haven't tried it this way, but it's got to be an improvement.