Launched in 1968, this Ted Irwin design represents one of the earlier entries in the production cruising sailboat market that would flourish throughout the following decades. The Irwin 31 combines traditional proportions with practical features that made it an attractive choice for coastal cruising and weekend sailing. With a displacement of 9,600 pounds and substantial ballast of 3,800 pounds, this masthead sloop offers reassuring stability for cruising sailors. The 7.5-foot draft provides good upwind performance while remaining manageable for most harbors and anchorages. The fiberglass construction with balsa-cored decking reflects quality building practices of the era, delivering both strength and reduced weight aloft. The boat's sail area of 448 square feet and SA/Displacement ratio of 15.92 indicate moderate performance characteristics well-suited to comfortable cruising rather than racing. The comfort ratio of 29.37 suggests a motion that favors seaworthiness over speed, while the capsize screening value of 1.81 falls within acceptable ranges for coastal sailing. Built by Irwin Yachts in the USA, this design helped establish the builder's reputation for producing affordable, well-constructed cruising boats. The 25-horsepower auxiliary engine provides adequate power for maneuvering and charging systems during extended cruising.
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What is the Irwin 31's sail area to displacement ratio?
The Irwin 31 has a Sail Area to Displacement ratio (SA/D) of 15.92. Values between 14–18 are typical cruising sailboats; 18–22 is cruiser/racer; over 22 is performance racing.
What is the Irwin 31's comfort ratio?
The Irwin 31 has a Ted Brewer Comfort Ratio of 29.37. A ratio over 30 indicates good offshore comfort; over 40 is very comfortable offshore.
Is the Irwin 31 safe for offshore sailing?
The Irwin 31 has a Capsize Screening Formula value of 1.81. Values under 2.0 are considered acceptable for offshore sailing; under 1.8 is ideal.
What is the hull speed of the Irwin 31?
The theoretical hull speed of the Irwin 31 is 6.32 kn knots, calculated from its waterline length.
How much does a Irwin 31 weigh?
The Irwin 31 has a displacement of 9,600.00 lb and a length overall (LOA) of 31.08 ft.
How much does a used Irwin 31 cost?
Based on 1 recent market listings, used Irwin 31 sailboats typically sell for between $5,500 and $5,500, with a median asking price of $5,500. Price varies significantly based on year, condition, location, and included equipment.
Who designed the Irwin 31?
The Irwin 31 was designed by Ted Irwin, first built in 1968.