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Islander 40
Designer: Doug Peterson  ·  Builder: Islander Yachts  ·  First built: 1979
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About the Islander 40

Launched in the early 1970s, this classic cruising sailboat emerged from Islander Yachts during the height of the fiberglass production boat boom. With her traditional design philosophy and robust construction, the Islander 40 quickly established herself as a capable coastal cruiser favored by sailors seeking reliable performance over racing speed. Built with a full keel configuration and heavy displacement hull, this yacht prioritizes stability and comfort over pure speed. Her design reflects the era's emphasis on seaworthiness, featuring a deep, protected cockpit and solid construction that inspires confidence in challenging conditions. The spacious interior layout typically accommodates extended cruising with generous headroom and practical storage solutions. While not designed for racing competition, the Islander 40 excels at coastal cruising and short offshore passages. Her forgiving sailing characteristics make her particularly appealing to couples or small crews planning extended adventures. The boat's reputation centers on durability and ease of handling rather than cutting-edge performance, representing the practical cruising philosophy that defined many successful designs of the 1970s. Today, well-maintained examples remain popular among sailors seeking traditional sailing characteristics in a proven, comfortable package.

Core Dimensions
LOA (Length Overall) 39.54 ft / 12.05 m
LWL (Waterline Length) 30.83 ft / 9.40 m
Beam 11.83 ft / 3.61 m
Max Draft 7.17 ft / 2.19 m
Displacement 17,000.00 lb / 7,711 kg
Ballast 7,700.00 lb / 3,493 kg
Sail Area (Reported) 734.00 ft² / 68.19 m²
Design & Construction
Hull Type Fin w/spade rudder
Rigging Type Masthead Sloop
Construction FG w/divinycell deck
Designer Doug Peterson
Builder Islander Yachts
First Built 1979
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Performance Ratios
SA/Displacement Sail Area to Displacement ratio measures how much sail power a boat has relative to its weight. Higher values mean more performance and speed.
Under 14 — Heavy cruiser, slow14–18 — Cruising sailboat18–22 — Cruiser/racerOver 22 — Performance racer
17.83
Comfort Ratio Ted Brewer's Comfort Ratio predicts how comfortable a boat will feel in offshore conditions. Higher values mean a steadier, more comfortable motion in a seaway.
Under 20 — Uncomfortably rough20–30 — Acceptable coastal30–40 — Good offshore comfortOver 40 — Very comfortable offshore
29.25
Capsize Screening Formula The USHS Capsize Screening Formula estimates offshore capsize risk. Lower is safer — values under 2.0 are considered acceptable for offshore sailing.
Under 2.0 — Safe for offshore2.0–2.2 — Borderline offshoreOver 2.2 — Coastal use recommended
1.84
Hull Speed Hull Speed is the theoretical maximum speed of a displacement hull, calculated from waterline length. Most cruising sailboats reach this speed in moderate conditions. 7.44
S# (Speed Number) The Speed Number (S#) is a quick performance index. Higher values indicate a faster, more powerful design relative to its size.
Under 3.0 — Slow cruiser3.0–5.0 — Average cruiser5.0–7.0 — Performance cruiserOver 7.0 — Racer
2.16
Pounds/Inch Immersion Pounds per Inch Immersion (PPI) tells you how much weight is needed to sink the boat one inch. Useful for calculating how additional gear and stores affect waterline. 1.0
Rig Dimensions
I (Foretriangle Height) 53.0
J (Foretriangle Base) 16.5
P (Mainsail Luff) 47.5
E (Mainsail Foot) 12.5
SA Fore 437.25
SA Main 296.88
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