In addition to his studies in physics and engineering while at Manual Arts High School and Los Angeles City College, Jacobson spent much of his time bodybuilding, street racing and working at an automotive garage.

Jacobson went to work in wholesale food for a short while, and while doing so met his wife, Dianna, with whom he'd have four children: Karen, Margo, Clayton 3 and Tava.

One day on the way home after a minor crash on the racetrack, Jacobson found himself taking a break in an irrigation ditch to have a beer with a friend while picking the gravel out of his wounds and lamenting that there had to be a way to enjoy the exhilaration and excitement of a motorcycle without the inherent danger of falling onto hard ground at high speeds.

This fixed-handlepole, stand-up design was constructed out of aluminum and powered by a West Bend two-stroke engine driving a Berkeley jet pump.

A second prototype, built in 1966, caught the attention of what was, at the time, primarily a snow-mobile manufacturer, Bombardier Recreational Products; and prompted the licensing of Jacobson's patents for the sit-down version of his jet-propelled personal watercraft that would become the Sea-Doo.

His development of the stand-up models continued through the late 1960s and early 1970s resulting in additional patents for a pivoting handlepole and a self-righting function.

The Rotax engine required a larger planing surface and sufficient induction for its air cooling, so Jacobson developed an entirely new sit-down model to adapt.