The other day when Tim was working on his foredeck hatch leak on the C-Dory, I suggested some super tape I’ve used for temporary leak protection. Tim got directed to some high-grade duct tape that promises to minimize the horrible, near permanent residue from regular duct tape. I was actually thinking of another product, 3M Preservation Sealing Tape, which costs-an-arm-and-a-small-piece-of-a-leg, like you’d expect of any good, marine-grade product (ahem). Its intended use is to supplement those plastic shrink wrap jobs that some folks use to store or transport boats. 3M claims that it comes off a year later without residue. It’s tough and thicker than most tapes. I’ve left it on surfaces in Mexico for a year, and from experience can say that it eventually crumbles in intense direct sunlight, and will leave a little yellowish stain on white fiberglass. It sticks very well to smooth surfaces and seals pretty well, but it does not stick well on rough surfaces like non-skid.
I originally tried preservation tape as a rigging tape on a sailboat we raced regularly, and it worked quite nicely for the purpose, and the 2 inch wide roll made it quick work to cover sharp pins and fittings. However, I’ve since learned that you really don’t want to put tape over any kind of stainless steel fittings or rigging, because it almost inevitably results in corrosion under the tape as salt water works it’s way under the edges. Stagnant salt water is terrible for stainless, because the corrosion protection of stainless relies on exposure to oxygen to maintain the protective oxide film on the metal’s surface. When you see a little rust-colored stain weeping from fittings on your boat, it’s the same problem, and a good sign that it’s time to pull the fitting and rebed it with a high quality sealant like polysulfide (try to avoid silicone unless you are bedding a plastic fitting that requires it).
Probably the best thing to do for covering sharp pins or fittings on a boat is to fit a nice piece of breathable leather or heavy fabric, with some kind of lacing or velcro that makes it easy to remove and inspect the fitting.