Long-tail boats are a type of watercraft native to Southeast Asia, which uses a common automotive engine as a readily available and maintainable powerplant. These craft are designed to carry passengers on the river and include a lightweight long canoe hull, up to 30 meters, and a canopy. There is much variation among these boats, and in rural areas they may be improvised from bamboo and traditional materials—the sole defining characteristic is a secondhand car or truck engine.

Thes engines are mounted on an inboard turret-like pole which can rotate through 180 degrees, allowing steering by thrust vectoring. The propeller is mounted directly on the driveshaft with no additional gearing or transmission. The engine also swivels up and down to provide a "neutral gear" where the propeller does not contact the water. The driveshaft must be extended by several meters of metal rod to properly position the propeller, giving the boat its name and distinct appearance.

Advantages to the inboard engine with a long driveshaft include keeping the engine relatively dry. Following the basic design pattern allows a variety of engines to be safely attached to a variety of different kinds of hulls. Control is achieved by moving the engine with a lever stick attached to the inboard side. Ignition and throttle controls provide simple means to control this simple craft. Larger boats may include more than one "tail," with several operators piloting in tandem.