The equipment your boat needs. Safety equipment is essential for your safety and the safety of others if you run into trouble. See the know your equipment section for more details. The type of engine and power the boat needs. Different types of engines are more suitable for certain uses and conditions than others.
Boats have both minimum power needs and maximum power limitations.
Don't overpower to gain more speed. The extra weight on the transom may imbalance the boat and lower the freeboard. What the boat should be made of. Hull compositions can be fibreglass, aluminium, wood or inflatable. What you need may depend on how and where you use, maintain and store your boat.