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Illustrations by Brett Affrunti

September 17, 1944: The European Theater. The German Army is defeated and in retreat, and the Allied troops will be home from the war by Christmas, or so they believe. Operation Market Garden is launched to seize and hold key bridges over vital waterways, ending with the Rhine River at Arnhem, that will open access to Germany’s industrial heartland and secure victory. British General Montgomery plans for thousands of troops to land by parachute and glider in what is still the largest airborne operation to date. Once the troops hit the ground, however, they are not graced with the smooth operation they were promised.

“The concept was originally for the men to be dropped on the bridge,” says Larry Stevenson, a collector and historian of antique outboards. “But they were dropped nowhere near the bridge and they had to slog it through the German troops to get there.” Major General John Frost actually made it to the bridge at Arnhem with his men, where they took the bridge, holding one side until running out of ammunition and being forced to surrender after four days.

Meanwhile, west of Arnhem, 2,200 British First Airborne troops never made it to the bridge at all. They ended up trapped by the Germans on a pocket of the Rhine about half a mile wide. The end looked near.


Luckily, the Allies had the means to save them: storm boats, 16-foot plywood craft powered by 250-pound, 50-hp Evinrude outboards. When the men got trapped, the storm boats were still in Belgium and had to be loaded onto trucks and driven down a 60-mile road under enemy fire just to get to the river. Getting the boats into the water was another feat. “They had to carry these boats up dikes about 20 feet high and manhandle them just to get them there,” Stevenson says. “Then they crossed in the middle of the night and saved all 2,200 of them who would have been slaughtered.”

The troops never secured the bridge at Arnhem and the operation was ultimately a failure. The operation did, however, put outboard power to the ultimate test in what was hailed as a miraculous rescue.

When America entered the war in 1941, it was all hands on deck. The country was in desperate need of troops, supplies and funds, and that meant complete cooperation between the government, industries and citizens. While young men flocked to the military, first by choice and then by draft, and propaganda campaigns rallied to get the American people behind the war effort, the government sourced supplies. Before America could invade Europe, it needed a fleet of storm boats.

Storm boats, also known as assault boats, were designed by the British and built in America. Troops needed a way to cross major rivers, as the enemy would detonate bridges in their wake. Right before America was set to begin operations in Europe, General Eisenhower called for an additional 400 storm boats; at the last minute, W.C. Meloon, founder of Pine Castle Boats in Pine Castle, Florida, got the contract. 

The city closed down its streets and set up saw horses. Meloon and his men worked 24 hours a day, every day except Sunday, for three weeks to get the job done. When those three weeks were up, Meloon proved good on his word and America had 400 additional vessels to bring to Europe.


The plywood craft were built with ribs across the bottom, making them sturdy enough to hit rocks. The genius behind the boat design was in the power: 50-hp Evinrude outboards—a huge jump in horsepower from the 5- to 10-hp engines available to boaters on the recreational market. “They needed 50 hp because rivers like the Rhine had an 8-knot current,” Stevenson says. “If you tried to paddle across like they show in the movies you would be 5 to 10 miles downstream by the time you got to the other side, and that’s where the Germans were.”

The boats were operated by two combat engineers, one at the tiller and one at the bow. While they directed the boat, nine men would lay in the bottom. The boats were propelled onto the beach at 25 mph, and the nine men would immediately roll out and start shooting. The combat engineers would turn the boat around to bring the rest of the troops across the river, and they would repeat the process until everyone was across.

Storm boats were critical in getting Allied troops across Europe, but outboards entered the war effort before the boats were even constructed. They were initially used to power portable water and fire pumps, following plans developed for the National Park Service.

The government wanted something that could be placed below decks on larger ships and could be used as a fire pump or to de-water ships with fractured hulls. They contacted Pacific Marine Supply, which was the largest Johnson dealer in the Northwest, and the company developed a design that later became pivotal in the war effort.

For the first pump they used two Johnson A-series outboard motor heads. “They were very light and very strong but it was only 4 hp and they needed 8 hp,” says Stevenson, “so they took two of them and welded a crankshaft on and made a four cylinder outboard motor that was light enough and strong enough [for their purposes].” Pacific Marine Supply then created a cast aluminum base and added water to mix with the exhaust so that all of the exhaust coming out was cooled water, which prevented fires.

The pumps were successful and the Navy adapted the design, adding another hose that went up to the deck to act as ventilation. Those pumps accounted for the survival of countless ships throughout the war, including the destroyer the USS Laffey, which was attacked off Okinawa, Japan. The portable pump displaced over 90,000 gallons of water from the ship, leading Laffey to earn the name “The ship that would not die” after surviving the D-Day invasion and the Battle of Okinawa.

Johnson outboards were also used to build floating bridges in Europe. The Johnson PO15 was a 22-hp rowboat engine that was attached to one section of a floating dock. “The first section of the bridge comes out with this outboard and it’s facing upstream,” Stevenson says. “The stream [current] is 8 knots and the engine is set for 8 knots so it holds it stationary against the bank. They would pin that section to the ground and the outboard keeps going. The next section comes up and matches up with that at 8 knots and they pin that section.” According to Stevenson, sometimes the Army would use 100 sections to get across a river with 100 outboards running.


If the outboards failed, the force of the river would have broken the floating bridge in two. After the bridge was in place, men would motor upstream and sink anchors attached to steel cables in the mud, and then bring the cables downstream and attach them to the bridge. This kept the bridge secure enough for trucks, tanks and foot soldiers to cross. Without this engineering, advancing across Europe would have been near impossible.

While Evinrude and Johnson helped the Allies physically traverse Europe, other outboard companies contributed to the war effort by supplying parts. Carl Kiekhaefer of Mercury Marine designed a two-man, 6-foot chainsaw when the country was struggling to source enough wood from the Pacific Northwest for the war effort. The chainsaws were powered by an air-cooled, twin engine outboard. Kiekhaefer himself campaigned his new chainsaw throughout the Pacific Northwest, challenging professional lumberjacks to log-cutting duels. “He beat the pants off of them and got people to use them,” Stevenson says. By the end of the war, Mercury was the world’s largest chainsaw manufacturer.

Outboards also powered the world’s first drones, which saved countless pilots’ lives. Reginald Denny, a successful Hollywood actor and model airplane enthusiast, teamed up with Walter Righter, an aircraft engine pioneer, to create a flying remote-controlled airplane. Up until that point, Denny had only been interested in model airplanes, but his pursuit in designing a flying model was important for the military, who sought a way to reduce pilot fatalities while flying target duty, when battery gunners would practice firing anti-aircraft artillery at their billowing target sleeves. 

Far from the lethal drones the military deploys today, these “radioplanes” were weaponless, used to keep pilots out of harm’s way. Prior to their development, the highest fatality rate among pilots were those who pulled target sleeves. Radioplanes and their engines changed everything.

“They had two cylinder and later four cylinder air-cooled engines by outboard manufacturers,” Stevenson says. “They were designed so that a parachute came out the top if it was hit and it would glide to the ground. They’d patch it up and send it back up.” The engines provided the planes with 6 hp. The Army ordered thousands of the radioplanes to be built. 

Among the assembly workers in the factories was a young woman named Norma Jeane Dougherty, whom Army photographer David Conover photographed for the first time in 1945 after being sent to write an article on the radioplane factories for the military newspaper Stars and Stripes. Norma Jeane’s modeling career took off from there, and she later changed her name to Marilyn Monroe.

Outboard technology propelled the Allies to victory, and while it is impossible to say for certain if the war would have been won without them, they saved many lives, making their contribution invaluable. “Eisenhower thought that we really would have had a lot of trouble winning the war without outboards,” Stevenson says. “If you’re going to paddle across, which is the tradition, it just didn’t work.”

The Germans had their own version of a storm boat, but their outboard was a radically different design. The engines were horizontally mounted to the transom with no lower unit and the shaft went straight back. “The guy moving the boat with a tiller had to be really strong because there were 10 feet out behind the bottom of the boat,” Stevenson says. The engines did not compare to the Evinrudes on the Allied storm boat fleet. The Japanese had outboards as well, but they were made by an aircraft company that was out of its element and they were not of comparable quality. The difference in outboards between the opposing nations was a difference in troops saved, lands conquered and battles won.

The outboard’s aid in winning the war was rewarded by a subsequent boom in the industry. Prior to the war, most outboard motors were no more than 5- to 10-hp fishing engines. After, the middle class grew with the GI Bill and a recharged economy. Watersports grew in popularity and with them a new need for outboard power. A horsepower race started between the major outboard companies and by 1958 there were 50-hp outboards available to consumers. In 1962, Mercury released the world’s first 100-hp outboard.

Stevenson donated his collection of over 200 antique outboards, many of which are from World War II, to the LeMay Family Collection in Tacoma, Washington, where they can be viewed by the public. The collection can put into perspective just how innovative a 50-hp storm boat outboard was, or how much impact a 22-hp rowboat engine could have, especially now that it’s common to have hundreds of horsepower on the transom. Outboards infiltrated every part of the war effort and aided the Allies in their victory, one river at a time.

This article originally appeared in Outboard magazine, a sister publication in the AIM Marine Group.