While similar to what is under the hood of your car, gas engines used in marine applications are modified to make them marine engines. Gasoline inboard engines range in horsepower from 90 HP to over 1000 HP per engine and are used in a variety of engines from tow sport boats to large cruisers.
In an inboard engine configuration, the engine sits amidships, with a drive running through the bottom of the boat to a propeller, with a separate rudder used for steering. A transmission is often used to transfer power from the engine to the propeller. Exhaust is passed through the stern of the boat. Inboards are also common for tow sports such as waterskiing, wakeboarding as they allow the propeller to be brought forward of the back of the boat, providing area for platforms to assist skiers in entering and exiting the boat.
- Simple drive system can lower maintenance
- No means to trim propeller
- Low running costs
- Quite and out of the way