By Matt Claiborne
A sterndrive is a type of marine engine configuration that goes by several different names. Sometimes it’s called an outdrive, and other times an inboard-outboard, or I/O.
One unit–engine, transmission, and propeller–all mounted externally on a boat’s transom. Outboards are typically seen on dinghies, tenders, johnboats, skiffs, pontoon boats, fishing boats, small sailboats (less than 25 feet), and some small power cruisers.
An inboard motor is internally mounted inside the boat. Inboards are found on ski boats, traditional fishing boats, some small powerboats, large sailboats, trawlers, motor yachts, and ships.
Inboard-outboards, sterndrives, or whatever you call them, are only common on bowriders, wakeboarding boats, and express cruisers.