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You are looking at a preview of what’s in the timed Vermont Boat Ed Course. Feel free to look around, but you’ll need to register to begin progress toward getting your Vermont Boating Safety Education Certification Card.

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Stern Drives

Stern drive engine
Stern drives have quieter and more fuel-efficient engines.
  • Stern drives are known also as inboard/outboards (I/Os) because they combine features found on both inboard and outboard engines. Stern-drive engines are four-stroke automotive engines adapted for marine use and are mounted inside the boat.
  • A stern-drive engine is attached through the transom to a drive unit (also called an "outdrive") that is essentially the lower unit of an outboard. The engine turns a drive shaft that is attached to a propeller at the other end.
  • Steering of stern-drive boats is controlled by the outdrive, which swivels like an outboard engine to direct propeller thrust.