GPSActionReplay

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 n1 = 72,5km/h [39,2Knots] (282,1 m. in 14,0 s.)
250 meter run n2 = 72,3km/h [39,0Knots] (281,2 m. in 14,0 s.)
250 meter run n3 = 71,6km/h [38,6Knots] (278,3 m. in 14,0 s.)
250 meter run n4 = 70,6km/h [38,1Knots] (274,4 m. in 14,0 s.)
250 meter run n5 = 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 n1 = 67,3km/h [36,3Knots] (523,2 m. in 28,0 s.)
500 meter run n2 = 67,2km/h [36,3Knots] (522,8 m. in 28,0 s.)
500 meter run n3 = 67,0km/h [36,2Knots] (520,9 m. in 28,0 s.)
500 meter run n4 = 66,3km/h [35,8Knots] (515,6 m. in 28,0 s.)
500 meter run n5 = 65,9km/h [35,6Knots] (512,3 m. in 28,0 s.)



Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'gpsactionreplay'@'172.20.245.57' (using password: YES) in /mnt/132/sda/2/c/gpsactionreplay/log/connect.inc.php on line 12
Could not connect