IRREVERSIBLE — ORC Rating

GPH

763.9

OSN

738

LOA

9.39 m

Displacement

6960 kg

Triple-Number Ratings

Lower is faster

Triple Inshore

Low

0.5176

Medium

0.7174

High

0.854

Triple Offshore

Low

0.669

Medium

0.8932

High

1.0238

Boat Specifications

Dimensions

Length overall: 9.39 m
Beam: 2.91 m
Draft: 1.56 m
Displacement: 6960 kg
Crew weight: 160 kg
Wetted surface: 24.89 m²

Sails

Mainsail: 18.48 m²
Genoa: 35.75 m²
Spinnaker: 68.9 m²
Asymmetric spinnaker: 0 m²

Design

Type: WESTERLY LB 31
Builder: WESTERLY
Designer: Jack Laurent Giles
Year built: 1971

Velocity Prediction

Polar CSV

Each row is TWS followed by TWA and boat-speed pairs. Paste it directly into WX Navigator or compatible navigation software.

6,46.1,3.792895,52,4.13,60,4.41,75,4.6,90,4.55,110,4.57,120,4.44,135,3.99,147.6,3.529434,150,3.44
8,44.2,4.477546,52,4.92,60,5.19,75,5.4,90,5.38,110,5.55,120,5.43,135,5,150,4.42,151.4,4.362271
10,43.5,4.97674,52,5.49,60,5.76,75,5.98,90,6.06,110,6.23,120,6.16,135,5.84,150,5.26,153.4,5.110975
12,43.1,5.382365,52,5.9,60,6.13,75,6.33,90,6.46,110,6.61,120,6.57,135,6.37,150,5.95,158.6,5.628019
14,42.7,5.660522,52,6.16,60,6.36,75,6.55,90,6.71,110,6.88,120,6.86,135,6.71,150,6.41,170.3,5.894268
16,42.5,5.818706,52,6.32,60,6.51,75,6.72,90,6.89,110,7.12,120,7.12,135,6.98,150,6.72,177.4,6.276461
20,42.4,5.958383,52,6.47,60,6.69,75,6.97,90,7.11,110,7.57,120,7.62,135,7.5,150,7.22,179,6.851043
24,42.9,6.020125,52,6.53,60,6.77,75,7.14,90,7.38,110,7.84,120,8.1,135,8.04,150,7.74,179,7.331117

Wind Speed	52°	60°	75°	90°	110°	120°	135°	150°
6	4.13	4.41	4.6	4.55	4.57	4.44	3.99	3.44
8	4.92	5.19	5.4	5.38	5.55	5.43	5	4.42
10	5.49	5.76	5.98	6.06	6.23	6.16	5.84	5.26
12	5.9	6.13	6.33	6.46	6.61	6.57	6.37	5.95
14	6.16	6.36	6.55	6.71	6.88	6.86	6.71	6.41
16	6.32	6.51	6.72	6.89	7.12	7.12	6.98	6.72
20	6.47	6.69	6.97	7.11	7.57	7.62	7.5	7.22
24	6.53	6.77	7.14	7.38	7.84	8.1	8.04	7.74

Wind Speed	Beat Angle	Beat VMG	Run Angle	Run VMG
6	46.1°	2.63	147.6°	2.98
8	44.2°	3.21	151.4°	3.83
10	43.5°	3.61	153.4°	4.57
12	43.1°	3.93	158.6°	5.24
14	42.7°	4.16	170.3°	5.81
16	42.5°	4.29	177.4°	6.27
20	42.4°	4.4	179°	6.85
24	42.9°	4.41	179°	7.33

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