Owners of aluminum boats make guests empty their pockets of loose change, because a penny in the bilge of an aluminum boat will punch a hole in the hull. I did

Owners of aluminum boats make guests empty their pockets of loose change, because a penny in the bilge of an aluminum boat will punch a hole in the hull. I did make a mistake; has to be an old style copper penny for maximum galvanic corrosion. It's a fairly lousy material for boats, though people use it anyway.