Back in 1967, Laurent Beaudoin had a vision. And that vision, was to put the famed "Ski-Doo" on the water. But, that vision wouldn't have been there if it wasn't for Clayton Jacobsen II. The inventor of the stand-up Kawasaki Jet-Ski, also invented the first PWC (Personal WaterCraft). Jacobsen was an aspiring inventor and ex-banker from Southern California. He had gotten the idea from motorcycles, thinking how cool it would be to ride one on the water. This was when Beaudoin approached him about the idea for the Sea-Doo in 1967.
Mr. Beaudoin had been trying to create the affect of snowmobiles on the water. When this came along he jumped right on it. Jacobsen's design was unique, because it used a jet pump to drive the vehicle rather than an outboard motor. Although at the time, Jacobsen was designing the stand-up rather than the sit-down. Once Sea-Doo sent him an 18-hp Rotax engine, did he start the design of the sit-down.
What differed about this engine was rather than being water-cooled like engines are now, it was air-cooled. So he had a little bit of trouble designing the hull to accommodate the needed air. After Jacobsen had completed a model for Bombardier, they bought the rights to the design and gave Jacobsen a fat check. Then Bombardier took over and rounded out the hood, and added the Sea-Doo famous yellow and black paintjob.
In 1969, Sea-Doo updated the original 318cc engine with a 372cc engine. The new 372 engine allowed liquid-cooling rather than air, which solved many reliability problems associated with the 318 engine. Some things that were the same on the '68-'70 models, was a bench seat which sat one person, a removeable gas tank, and steel handlebars which were taken directly from the Ski-Doo.
Although it may have looked good on paper, there were some factors which ended production in 1970 until 1988. First of course was the problem with the air-cooled engine on the 1968 model. This engine didn't perform well under the extreme conditions within the hull. The 372 engine, which introduced water-cooling didn't solve all the problems. Since most of the skis were sold on the East coast, salt water was a big problem. Marine technology hadn't caught up to the Sea-Doo in the 3 years it was around, so corrosion was a big matter. It ate up everything. The engine, pump, controls, and many other problems. Jacobsen had certain design ideas like rubber motor mounts, a rubber dampner for the driveshaft coupler, and ways to waterproof the electronics - but no one would listen to him once he delivered the original prototype.
Bombardier was too worked into the snowmobile market they didn't really have time to produce the Sea-Doo effectively. The snowmobile market was just huge, with Bombardier not being able to keep up with demand. Thus, the Sea-Doo sank away until 1988. Jacobsen got his patent back in 1971 and thus, sold them to Kawasaki - a deal that led eventually to creation of the Jet Ski.