Boating Stickers Hull's Deep Buoyancy Indicator- Put this sticker on your boat!. 6\" x 2\" Marine-grade stickers. Put this sticker on your boat to mark where the water line should be. You'll be able to detect even small amounts of buoyancy loss with this well-placed sticker on the side or back of your boat. Buy a few stickers and put one on your cooler and one on your truck while you're at it.