GPSActionReplay
Analyses
Speed-board

Description

Speed windsurfing requires strong winds and flat water (from 20 to 45-50 knots).
The boards are narrow (from 45 cm to 55 cm), and sails are big enough to cope with very deep downwind runs (usually 5.5 to 7.0 sq-meters depending on the wind). Fins, on the contrary, are as small as possible to generate as less drag as possible (less than 32 cm).
This analysis is built from a Martin Van Meurs's track (sept. 2004). Because of the spot not being large, the averages are computed over 500 meters rather than 2000 meters.

Track shape overview

Polar/VMG diagram

Upwind and Downwind Analysis

Typical behaviors over 500 meters

Upwind

Downwind

Typical values over 500 meters

NameDateWind directionTackSpeedVMGAngle to windLengthDuration

Trajectoire 0

Tue Sep 14 17:16:13 CEST 2004214Port20,4288,65265504,43648,000

Trajectoire 0

Tue Sep 14 17:08:23 CEST 2004214Starboard35,507-28,401138511,45928,000

Trajectoire 0

Tue Sep 14 17:10:22 CEST 2004214Port34,894-15,422117502,63428,000

Trajectoire 0

Tue Sep 14 17:14:30 CEST 2004214Starboard34,095-22,896131526,19530,000

Trajectoire 0

Tue Sep 14 14:54:17 CEST 2004214Port20,9697,41169517,78948,000

Apparent wind analysis

Upwind

Downwind

Not a lot to say as far as upwind is concerned when speedsurfing. The angle is not close to wind, but a good 20 knots speed enable a good 8 knots VMG. Apparent Wind here is about 40 knots with a 30 knots wind. Very different from downwind.

Amazing! The apparent wind gets a 45° shift within some meters, when Martin is going deeply downwind, and is 90° oriented from true wind.

The apparent wind speed drops from 40 to 25 knots (5 knots below true wind, 10 knots below board speed).

Top speeds auto analysis


5 best 250 meter (at least) average = 71,3km/h [38,5Knots]

250 meter run n°1 = 72,5km/h [39,2Knots] (282,1 m. in 14,0 s.)
250 meter run n°2 = 72,3km/h [39,0Knots] (281,2 m. in 14,0 s.)
250 meter run n°3 = 71,6km/h [38,6Knots] (278,3 m. in 14,0 s.)
250 meter run n°4 = 70,6km/h [38,1Knots] (274,4 m. in 14,0 s.)
250 meter run n°5 = 69,8km/h [37,7Knots] (271,3 m. in 14,0 s.)

5 best 500 meter (at least) average = 66,7km/h [36,0Knots]

500 meter run n°1 = 67,3km/h [36,3Knots] (523,2 m. in 28,0 s.)
500 meter run n°2 = 67,2km/h [36,3Knots] (522,8 m. in 28,0 s.)
500 meter run n°3 = 67,0km/h [36,2Knots] (520,9 m. in 28,0 s.)
500 meter run n°4 = 66,3km/h [35,8Knots] (515,6 m. in 28,0 s.)
500 meter run n°5 = 65,9km/h [35,6Knots] (512,3 m. in 28,0 s.)


Speed-board