Have to admit I don't fully understand galvanic action in marinas. (Today I went to a sheltered marina in prep for Earl.)

My boat normally lives on a mooring far from any shore power or other boats, and isn't bonded: No metal parts that contact the water are connected to anything that carries a current (possible exception being the raw water intake which is connected to the engine by the water in the hose). My prop shaft is isolated from the transmission by a flexible coupling.

So if I go into a "hot" marina or tie up near a "hot" boat, how vulnerable is my boat to current-induced galvanic corrosion? Would a zinc "fish" make a difference?