How Ole Evinrude Invented the Modern Portable Outboard Motor

A 1911 patent for a compact, detachable marine engine that allowed small boats to be powered by a portable, gasoline-driven propeller unit.

What it covers

The patent describes a self-contained marine propulsion unit designed to be clamped onto the stern of a small rowboat. It integrates the gasoline engine, the vertical drive shaft, and the propeller into a single, portable assembly. By mounting the motor externally, it removes the need for heavy, permanent inboard engines, effectively turning a standard rowboat into a motorized vessel.

What it doesn't cover

• —Does not cover electric outboard motors or battery-powered propulsion systems.
• —Does not cover inboard engines where the motor is mounted inside the hull.
• —Does not cover jet-drive propulsion systems that lack a traditional propeller.

The clever bit

The innovation was the extreme integration of the engine and propeller into a single, lightweight, clamp-on unit that could be easily transported and attached by one person.

Why it matters

This invention fundamentally changed recreational boating by making it affordable and accessible to the average person. Before this, motorized boats were large, expensive, and required permanent installation, but Evinrude's design allowed anyone to attach an engine to their existing rowboat.

Real-world examples

• 1.Evinrude portable outboard motors
• 2.Modern small-craft fishing outboards
• 3.Inflatable boat motors