Fortissimo: ORC Rating

GPH

605.1

OSN

590.7

LOA

9.55 m

Displacement

3020 kg

Triple-Number Ratings

Lower is faster

Triple Inshore

Low

0.692

Medium

0.9015

High

1.0127

Triple Offshore

Low

0.8891

Medium

1.1075

High

1.2317

Boat Specifications

Dimensions

Length overall: 9.55 m
Beam: 2.96 m
Draft: 2.1 m
Displacement: 3020 kg
Crew weight: 465 kg
Wetted surface: 20.91 m²

Sails

Mainsail: 34.36 m²
Genoa: 31.72 m²
Spinnaker: 0 m²
Asymmetric spinnaker: 96.22 m²

Design

Type: Grand Surprise 31
Builder: Archambault
Designer: Joubert Nivelt
Year built: 2000

Performance data

Polar CSV

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

6,42,4.978841,52,5.6,60,5.9,75,6.16,90,6.13,110,6.03,120,5.89,135,5.25,144,4.73414,150,4.43
8,40.5,5.865288,52,6.56,60,6.76,75,6.89,90,6.91,110,7.02,120,6.94,135,6.51,147,5.723344,150,5.54
10,38.6,6.257034,52,6.93,60,7.09,75,7.26,90,7.3,110,7.52,120,7.49,135,7.18,149,6.591479,150,6.52
12,37.5,6.390595,52,7.06,60,7.25,75,7.55,90,7.68,110,7.92,120,8.09,135,7.72,150,7.11,151.5,7.020801
14,36.9,6.440039,52,7.13,60,7.35,75,7.74,90,8.07,110,8.25,120,8.61,135,8.39,150,7.48,175,6.57502
16,37.1,6.482076,52,7.18,60,7.4,75,7.86,90,8.38,110,8.59,120,9.02,135,9.18,150,7.97,177,7.049661
20,36.8,6.556506,52,7.28,60,7.52,75,7.99,90,8.67,110,9.24,120,9.84,135,10.92,142.8,10.382535,150,9.55

Wind Speed	52°	60°	75°	90°	110°	120°	135°	150°
6	5.6	5.9	6.16	6.13	6.03	5.89	5.25	4.43
8	6.56	6.76	6.89	6.91	7.02	6.94	6.51	5.54
10	6.93	7.09	7.26	7.3	7.52	7.49	7.18	6.52
12	7.06	7.25	7.55	7.68	7.92	8.09	7.72	7.11
14	7.13	7.35	7.74	8.07	8.25	8.61	8.39	7.48
16	7.18	7.4	7.86	8.38	8.59	9.02	9.18	7.97
20	7.28	7.52	7.99	8.67	9.24	9.84	10.92	9.55

Wind Speed	Beat Angle	Beat VMG	Run Angle	Run VMG
6	42°	3.7	144°	3.83
8	40.5°	4.46	147°	4.8
10	38.6°	4.89	149°	5.65
12	37.5°	5.07	151.5°	6.17
14	36.9°	5.15	175°	6.55
16	37.1°	5.17	177°	7.04
20	36.8°	5.25	142.8°	8.27

VPP POLAR · BOAT SPEED BY TWAKT

TRUE WIND ANGLE —

READ AT ANGLE

Hover or tap the chart, or use the slider, to read boat speeds.

True wind speed 6 kt8 kt10 kt12 kt14 kt16 kt20 kt

Data table

Boat speed by true wind angle and true wind speed
TWA	Boat speed in 6 kt (kt)	Boat speed in 8 kt (kt)	Boat speed in 10 kt (kt)	Boat speed in 12 kt (kt)	Boat speed in 14 kt (kt)	Boat speed in 16 kt (kt)	Boat speed in 20 kt (kt)
0°	0.00	0.00	0.00	0.00	0.00	0.00	0.00
52°	5.60	6.56	6.93	7.06	7.13	7.18	7.28
60°	5.90	6.76	7.09	7.25	7.35	7.40	7.52
75°	6.16	6.89	7.26	7.55	7.74	7.86	7.99
90°	6.13	6.91	7.30	7.68	8.07	8.38	8.67
110°	6.03	7.02	7.52	7.92	8.25	8.59	9.24
120°	5.89	6.94	7.49	8.09	8.61	9.02	9.84
135°	5.25	6.51	7.18	7.72	8.39	9.18	10.92
150°	4.43	5.54	6.52	7.11	7.48	7.97	9.55