In Our Wake: War Horse

What’s the most important outboard ever built? That’s a peril-fraught question, but in terms of impact on humanity, I’ll posit that the honor belongs to Johnson’s “PO” series Sea Horse. For without this sturdy, reliable little motor, the allies’ eastward advance across Europe’s rivers during World War II might have never happened.

Johnson launched the P series in 1926. The larger PO (and POL with a six-inch-longer driveshaft) dawned five years later. A simple two-stroke, the PO was a horizontally opposed two-cylinder, 29-cubic-inch motor that cranked 22 horsepower at 4,000 RPM. A trusty magneto system fired the spark plugs, and the double-jet venturi carburetor made it uber-reliable and serviceable. The PO weighed 115 pounds and with a 2.5 gallon gas tank could run for an hour at speed. It rotated 360 degrees so it didn’t “kick out” when reversing, and you started it by coiling a cord around the exposed flywheel. Controls were simple: off, choke, run, run fast.

During World War II, the military commissioned thousands of POLR models from Johnson. These held a quieter underwater exhaust that prevented full 360–degree rotation—and gained an added “R” reverse gear. Tens of thousands of POLRs helped usher troops and heavy equipment, and built enormous floating bridges. Soldiers attached the motor to flat-bottomed barges that held bridge sections called pontoons, which they maneuvered to hold in place against ripping currents as they lashed more and more pontoons together. In one section of the Rhine River, as many as 100 simultaneously running POLRs were used to keep 100 pontoons in place until they could be secured to the opposite bank. The stakes were enormous. Should the motors fail, the pontoon bridge would snap and wash downriver. “Without this bridge engineering and these outboards, advancing across Europe would have been near impossible,” said Antique Outboard Motor Club Officer and former OMC Executive Jack Aylsworth. “It was one of the Johnson brothers’ most significant do-it-all motors. And in many ways, it helped win the war.”

Read or Listen to “How the Outboard Helped Win World War II” here ▶