Designed by Bruce Kirby in 1980, this 23-foot sloop has earned recognition as both a competitive one-design racer and capable club boat. With 860 hulls built by Seidelman, the Sonar represents a successful blend of performance and accessibility that has made it popular among sailing programs and racing fleets worldwide. The boat's fractional sloop rig and fin keel with spade rudder configuration delivers responsive handling and solid upwind performance. At 2,100 pounds displacement with nearly half that weight in ballast, the Sonar offers good stability while remaining light enough for exciting sailing in moderate conditions. The generous sail area of 265 square feet provides plenty of power for competitive racing, yet remains manageable for recreational sailing. Bruce Kirby's design philosophy emphasizes clean lines and straightforward systems, making the Sonar an excellent choice for sailing education and club programs. The boat's reputation for durability and relatively simple maintenance has contributed to its longevity in fleets around the world. While primarily suited for protected waters and coastal sailing, the Sonar excels in competitive one-design racing where boat-handling skills and tactics matter more than equipment advantages.
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What is the Sonar's sail area to displacement ratio?
The Sonar has a Sail Area to Displacement ratio (SA/D) of 25.92. Values between 14–18 are typical cruising sailboats; 18–22 is cruiser/racer; over 22 is performance racing.
What is the Sonar's comfort ratio?
The Sonar has a Ted Brewer Comfort Ratio of 10.04. A ratio over 30 indicates good offshore comfort; over 40 is very comfortable offshore.
Is the Sonar safe for offshore sailing?
The Sonar has a Capsize Screening Formula value of 2.45. Values under 2.0 are considered acceptable for offshore sailing; under 1.8 is ideal.
What is the hull speed of the Sonar?
The theoretical hull speed of the Sonar is 5.98 kn knots, calculated from its waterline length.
How much does a Sonar weigh?
The Sonar has a displacement of 2,100.00 lb and a length overall (LOA) of 23.00 ft.
Who designed the Sonar?
The Sonar was designed by Bruce Kirby, first built in 1980.