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Triangle One Design
Designer: John Alden  ·  Builder: James Graves  ·  First built: 1926
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About the Triangle One Design

Designed with competitive one-design racing in mind, the Triangle One Design is a class-focused sailboat built to deliver consistent, fair racing on the water. As a one-design vessel, every boat in the class is built to the same specifications, meaning results come down to sailor skill rather than equipment advantage — a quality that appeals strongly to racing enthusiasts looking for a level playing field. While detailed specifications are limited in available records, the Triangle One Design's very name suggests a boat well-suited to triangular windward-leeward course racing, a classic format that tests tacking, gybing, and strategic decision-making. This type of sailing typically favors responsive, nimble hulls that reward precise sail trim and tactical awareness. For those researching a potential purchase, the Triangle One Design may appeal most to sailors interested in active class racing within an established fleet. Prospective buyers are encouraged to seek out local class associations, as one-design boats often live and die by the health of their racing community. A strong local fleet can make ownership especially rewarding, offering regular competition and a ready network of fellow sailors.

Core Dimensions
LOA (Length Overall) 28.50 ft / 8.69 m
LWL (Waterline Length) 18.50 ft / 5.64 m
Beam 7.50 ft / 2.29 m
Max Draft 4.75 ft / 1.45 m
Displacement 5,017.00 lb / 2,276 kg
Ballast 2,500.00 lb / 1,134 kg
Sail Area (Reported) 407.00 ft² / 37.81 m²
Design & Construction
Hull Type Fin Keel
Rigging Type Fractional Sloop
Construction Wood
Designer John Alden
Builder James Graves
First Built 1926
Last Built 1933
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Known Issues & What to Watch For

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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
22.29
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
24.62
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
1.75
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. 5.76
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
1.8
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. 495.77
Rig Dimensions
I (Foretriangle Height) 22.8
J (Foretriangle Base) 8.25
P (Mainsail Luff) 37.5
E (Mainsail Foot) 19.2
SA Fore 94.05
SA Main 360.0
How It Compares

vs. Cambridge Cadet, Rhodes Ranger 29, Yachting World Seahorse

This boat Similar boats
Dimensions
LOA
Triangle One Design ★
28.5 ft
Cambridge Cadet
28.6 ft
Rhodes Ranger 29
28.5 ft
Yachting World Seahorse
28.6 ft
LWL
Triangle One Design ★
18.5 ft
Cambridge Cadet
Rhodes Ranger 29
20.0 ft
Yachting World Seahorse
25.3 ft
Beam
Triangle One Design ★
7.5 ft
Cambridge Cadet
8.6 ft
Rhodes Ranger 29
8.0 ft
Yachting World Seahorse
8.3 ft
Displacement
Triangle One Design ★
5 lbs
Cambridge Cadet
15 lbs
Rhodes Ranger 29
7 lbs
Yachting World Seahorse
6 lbs
Ballast
Triangle One Design ★
2 lbs
Cambridge Cadet
4 lbs
Rhodes Ranger 29
2 lbs
Yachting World Seahorse
2 lbs
Sail Area
Triangle One Design ★
407 sq ft
Cambridge Cadet
Rhodes Ranger 29
328 sq ft
Yachting World Seahorse
366 sq ft
Performance
SA / Displacement (higher = more powerful)
Triangle One Design ★
22.3
Cambridge Cadet
Rhodes Ranger 29
13.2
Yachting World Seahorse
17.8
Comfort Ratio (higher = more comfortable offshore)
Triangle One Design ★
24.6
Cambridge Cadet
53.1
Rhodes Ranger 29
34.2
Yachting World Seahorse
21.0
Capsize Screening (lower = safer)
Triangle One Design ★
1.75
Cambridge Cadet
Rhodes Ranger 29
1.60
Yachting World Seahorse
1.84
Hull Speed
Triangle One Design ★
5.8 kts
Cambridge Cadet
6.6 kts
Rhodes Ranger 29
6.0 kts
Yachting World Seahorse
6.7 kts
Speed Number (higher = faster)
Triangle One Design ★
1.8
Cambridge Cadet
Rhodes Ranger 29
0.8
Yachting World Seahorse
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