Inboard engines are a type of marine engine installed inside the hull of a boat. They are typically used in larger vessels, providing power to the boat's propeller through a drive shaft. This design helps to keep the engine protected from water and allows for better weight distribution. These engines are often favored for their durability and efficiency, making them suitable for various activities like fishing, cruising, and water sports. Inboard engines can be powered by gasoline or diesel, with diesel engines generally offering better fuel efficiency and longevity.