The Sonar is a recreational keelboat, built predominantly of fibreglass, with wood trim. It has a fractionalsloop rig with aluminum spars, including a tapered boom, a raked stem, a reverse transom, an internally mounted spade-type rudder controlled by a tiller with an extension and a fixed fin keel. It displaces 2,100 lb (953 kg) and carries 930 lb (422 kg) of lead ballast.[1][3]
The boat has a draft of 3.92 ft (1.19 m) with the standard keel.[1]
The design has a cockpit 11.50 ft (3.51 m) long, with space for eight people. It has a small cuddy cabin that is used for stowage and can also house a portable head. The cuddy can also be fitted with two berths for sleeping accommodation.[3][8]
The boat is supported by an active class club that organizes racing events, the Sonar Class Association.[11]
In a 1994 review Richard Sherwood wrote, "the Sonar was designed for the same market as the Etchells 22, Soling, Tempest, and Ensign. The basic concept was generated by a committee of the Noroton Yacht Club (Connecticut), then designed by Bruce Kirby. The cockpit is huge ... Only three sails are allowed — main, jib, and spinnaker."[3]
The boat was inducted into the American Sailboat Hall of Fame in 2004. The citation noted, "the brainchild of Bruce Kirby (who also designed the Laser, which was inducted into the American Sailboat Hall of Fame in 1997), the Sonar was designed to a specific set of parameters determined through a survey of club sailors. All were looking for the same thing—a boat that was exciting to race, easy to handle by sailors of varying ages and abilities, trailerable, self-bailing and reasonably comfortable. Basically, Kirby said, "we wanted a boat that could be sailed without breaking your neck." "I think it’s the best boat I ever designed in that it met all the criteria," Kirby said."[4]