Scow

A scow, in the unique sense, is a flat bottomed boat with a blunt bow, frequently used to haul garbage or related bulk freight; cf. barge. The etymology of the word is from Dutch schouwe, denotes such a boat.

Formerly an American design but also used in New Zealand the schooner rigged scow was extensively used for coastal and inland transport from around 1850 through the early 1900s. Scow schooners had a wide, thin hull, and used centerboards, bilge boards or leeboards fairly than a deep keel. The broad hull gave them stability, and the retractable foils permitted them to move yet heavy loads of cargo in waters far too shallow for keelboats to come in. The squared off bow and stern permitted the maximum amount of cargo to be carried in the hull. The least sailing scows were sloop rigged (creating them technically a scow sloop), but otherwise alike in design. The scow sloop ultimately evolved into the inland lake scow, a kind of fast racing boat.

Punt

A punt is a flat-bottomed boat with a square-cut bow, planned for use in small rivers or other shallow water. Punting refers to boating in a punt; the punter normally propels the punt by pushing beside the river bed with a pole.

Punts were initially built as cargo boats or platforms for fowling and angling but in modern times their use is almost wholly confined to pleasure trips on the rivers in the university towns of Oxford and Cambridge in England and races at a few summer regattas on the Thames.
A customary river punt differs from many other types of wooden boat in that it has no keel, stem or sternpost. In its place it is built rather like a ladder with the main structure being two side panels connected by a series of 4 in (10 cm) cross planks, known as "treads", spaced about 1 foot (30 cm) apart.

The first punts are traditionally linked with the River Thames in England and were built as small cargo boats or platforms for fishermen. Pleasure punts — particularly built for recreation — became popular on the Thames between 1840 and 1860. Some other boats have a similar shape to a traditional punt — for example the Optimist training dinghy or the air boats used in the Everglades — but they are normally built with a box construction instead of the open ladder-like design of a traditional Thames pleasure punt.

Motorboat

A motorboat generally speaking is a vessel other than a sailboat or personal watercraft, propel by an internal combustion engine driving a jet or a propeller. Though, the International Regulations for Preventing Collisions at Sea defines it as any vessel propelled by machinery. A speedboat is a small motorboat intended to move quickly, used in races, for pulling water skiers, as patrol boats, and as fast-moving armed attack vessels by the military. Even inflatable boats with a motor attached which may be serving as a high speed patrol boat or as a slow pedestrian dingy providing transport to and from a mooring buoy are technically classified as motorboats.
Here there are three popular variations of power plants: inboard, inboard/outboard, and outboard. If the engine is installed within the boat, it's called a power plant; if it's a detachable module attached to the boat, it's commonly known as an outboard motor.
An outboard motor is installed on the rear of a boat and contains the internal burning engine, the gear reduction (Transmission), and the propeller.