Which type of engine is described as portable and attaches to the transom?

The outboard engine is designed to be portable and is mounted on the transom, which is the flat vertical section at the back of a boat. This type of engine combines the engine and propeller into one unit that sits outside the hull, making it easy to remove and transport when not in use. Outboard engines are favored for smaller boats because they allow for more deck space, and they can be adjusted in height to accommodate different water conditions and performance needs.

Inboard engines, on the other hand, are installed within the boat's hull and require a more complex setup, making them less portable. Stern drives, while mounted at the back of the boat like outboards, are not considered portable in the same way because they are integrated into the boat's structure and require more effort to detach. Jet drives utilize a different mechanism altogether, relying on water propulsion instead of a conventional propeller, and are also typically embedded within the boat's hull.

The design and functionality of outboard engines make them the ideal choice for those looking for a portable option that can easily be attached and detached from the transom.