UNDERWOOD — ORC Rating

GPH

744.2

OSN

720.4

LOA

9.32 m

Displacement

5098 kg

Triple-Number Ratings

Lower is faster

Triple Inshore

Low

0.5418

Medium

0.7401

High

0.8637

Triple Offshore

Low

0.6965

Medium

0.9136

High

1.0272

Boat Specifications

Dimensions

Length overall: 9.32 m
Beam: 3.29 m
Draft: 1.82 m
Displacement: 5098 kg
Crew weight: 350 kg
Wetted surface: 21.07 m²

Sails

Mainsail: 19.83 m²
Genoa: 33.03 m²
Spinnaker: 70.88 m²
Asymmetric spinnaker: 0 m²

Design

Type: DUFOUR 31
Builder: TAYLOR
Designer: M. DUFOUR
Year built: 1975
Stability index: 123.7

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.

6,44.1,3.85726,52,4.27,60,4.53,75,4.72,90,4.67,110,4.76,120,4.62,135,4.22,147.8,3.722554,150,3.63
8,42.3,4.502244,52,5.03,60,5.31,75,5.54,90,5.59,110,5.76,120,5.64,135,5.17,150,4.58,152,4.496303
10,41.8,5.030343,52,5.65,60,5.9,75,6.08,90,6.21,110,6.33,120,6.28,135,6.01,150,5.41,152,5.323079
12,42,5.490182,52,6.02,60,6.2,75,6.35,90,6.5,110,6.65,120,6.61,135,6.43,150,6.09,158.3,5.790347
14,41.2,5.67506,52,6.2,60,6.37,75,6.53,90,6.62,110,6.92,120,6.9,135,6.72,150,6.45,172.7,5.978459
16,40.6,5.742348,52,6.29,60,6.47,75,6.68,90,6.78,110,7.15,120,7.19,135,7.02,150,6.72,179,6.330964
20,40.8,5.799245,52,6.34,60,6.54,75,6.87,90,7.1,110,7.4,120,7.65,135,7.6,150,7.29,179,6.851043

Wind Speed	52°	60°	75°	90°	110°	120°	135°	150°
6	4.27	4.53	4.72	4.67	4.76	4.62	4.22	3.63
8	5.03	5.31	5.54	5.59	5.76	5.64	5.17	4.58
10	5.65	5.9	6.08	6.21	6.33	6.28	6.01	5.41
12	6.02	6.2	6.35	6.5	6.65	6.61	6.43	6.09
14	6.2	6.37	6.53	6.62	6.92	6.9	6.72	6.45
16	6.29	6.47	6.68	6.78	7.15	7.19	7.02	6.72
20	6.34	6.54	6.87	7.1	7.4	7.65	7.6	7.29

Wind Speed	Beat Angle	Beat VMG	Run Angle	Run VMG
6	44.1°	2.77	147.8°	3.15
8	42.3°	3.33	152°	3.97
10	41.8°	3.75	152°	4.7
12	42°	4.08	158.3°	5.38
14	41.2°	4.27	172.7°	5.93
16	40.6°	4.36	179°	6.33
20	40.8°	4.39	179°	6.85

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