John Murdock, who died February 16 at 87 at his home in Swarthmore, Pa., was a mechanical engineer who developed the countercurrent swimming machine and patented the CarTurn, a kind of lazy susan for automobiles.

Originally developed as a safety device to prevent drivers from needing to back out of driveways into busy streets, the CarTurn has become popular among people with small driveways and garages, as well as “people with big garages who like to spin their cars,” the president of Endless Pools, Inc., and a son of Murdock, James Murdock, told The New York Sun.

The countercurrent swimming machine, which uses a propeller to simulate a current, was not a new idea; the first models were patented in the early 20th century, James Murdock said. Conceived by John Murdock as an exercise machine, Endless Pools became more popular as medical rehabilitation devices and also came to have unexpected uses, such as swimming pools aboard cruise ships. The polar bears at the Central Park Zoo use one in lieu of actual Arctic dips.

Murdock was born June 6, 1919, and grew up in Arizona, where his father was a New Dealer and congressman from 1936. Murdock got his engineering degree at the Massachusetts Institute of Technology in 1941. During World War II, he worked as supervisor of the MIT’s Montauk Point radar station, which mostly detected flocks of migrating Canadian geese. At one point in 1942, a group of four German saboteurs landed at nearby Amagansett. The Germans eluded the radar station’s staff and made it to New York City before they were apprehended.

After the war, Murdock and a friend set up the Perlite Corp., an engineering consultancy that developed machinery to process the mineral perlite, which is similar to vermiculite, into a variety of industrial products, such as insulation, planting soil, and filtration products. Over several decades, Murdock traveled to Iran and Japan, designing perlite manufacturing facilities and helping assess local deposits of the mineral. He retired in 1989.

A habitual tinker, Murdock came up with all sorts of handy devices, including a haircutter with a builtin vacuum. Hard of hearing in one ear since his days in his college shooting club, Murdock worked on a number of designs for directional hearing aids. He favored functionality over aesthetics, James Murdock said, and the devices sometimes resembled oldfashioned ear trumpets tricked out with electronics.

Murdock’s biggest commercial success was the Endless Pool, which his son James developed into an independent business. In addition to its zoo and shipboard applications, the company has recently developed a device that can add a current to a single lane of a backyard pool.

Murdock’s favorite project of recent years was his scheme to help America achieve energy independence by situating nuclear reactors in coastal waters, where they would have access to unlimited cooling water. The waste would also be stored undersea, James Murdock, who helped his father with the plans, said.