A What’s the difference between dock fenders and marine boat fenders? Dock fenders are permanently mounted to the dock itself, providing consistent protection every time a boat pulls in. Marine boat fenders, on the other hand, are typically inflatable or foam cushions that hang from the side of a boat. While marine boat fenders are portable and adjustable, they can shift or be out of position during docking, allowing opportunity for impact related damage. Dock fenders—especially heavy-duty ones like Slammer Marine’s Integrated Dock Fender ®—offer more reliable protection, as these fenders are always in the right place, and reliable when you need them most.