Single Inboard's are powered by one engine, diesel or gas, with one propeller and a rudder positioned amidship directly behind the prop. This system will have either a "right handed" or "left handed" propeller. A right hand prop, for example, rotates in a clockwise direction (as viewed from behind) while moving ahead and counterclockwise when backing. A left hand prop rotates counterclockwise while moving ahead and clockwise when backing.