Some boats are powered by the propulsion system known as an outboard motor. The basic outboard motor parts for this kind of equipment are the powerhead, or the engine, which also includes the tiller. Next, there is the midsection, or the exhaust housing, which is the area where the mounting bracket can be found. Then last, there is the lower unit, or the gearbox. In this section one can find the anti-ventilation plate, water intake, propeller and skeg. This style of motor is most common with smaller boats.
The largest of outboard motors operates at 15 to 135 horsepower and is available in 2, 3 and 4 cylinder models. There is also the portable outboard motor that operates at 15 horsepower. This style is clamped to a boat. Given its portability, this type is most useful if one intends to use the motor with a variety of boats. The next type of outboard motor is electric-powered. This style is sometimes used as a second option for propelling on a larger boat. These can also be found on smaller boats in areas where the use of a gasoline motor is not permitted or by fishermen who are trying not to scare off their prey. A pump-jet option also exists and is useful for propulsion in shallow areas where an open propeller would not work. Lastly, diesel outboard motors exist, but are quite uncommon.
A variety of brands for this type of motor exist. These brands include Evinrude, Johnson, Mercury and Yamaha outboard motors. These products or parts for them can be found at boat manufacturers.
By 1905 the outboard motor had been successfully created by a Yale engineering student, Cameron Waterman. This engine has made automatically propelling small boats that would previously have been powered by paddles or oars possible. There are a variety of brands and styles of this motor for unique boating needs.