[1][2][3] The design was initiated as a commission from the members of the Noroton Yacht Club of Darien, Connecticut, United States.

Since 2015 the boat has been built by Rondar Raceboats in the UK and distributed manufacturer direct worldwide.

It has a fractional sloop 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.

[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.

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.