There are two basic types of boat hulls—displacement and planing.
Boats with displacement hulls move through the water by pushing the water aside and are designed to cut through the water with very little propulsion.
- If you lower a boat into the water, some of the water moves out of the way to adjust for the boat. If you could weigh that displaced water, you would find it equals the weight of the boat. That weight is the boat's displacement.
- Boats with displacement hulls are limited to slower speeds.
- A round-bottomed hull shape acts as a displacement hull. Most large cruisers and most sailboats have displacement hulls, allowing them to travel more smoothly through the water.