Some resources for Sailing Performance.
"The most important mission of an instrument system is correctly reporting wind
direction...if lifts or headers occur every time you tack or gibe, there is a problem with your instrument calibration. DeWiggler is the solution to this problem."
"Wind direction is derived from apparent wind
, boatspeed and heading. Wiggle is reduced by correctly calibrating these three inputs."
DeWiggler - Ockam Sailing Instruments
Importance of true wind http://www.ockam.com/2013/05/17/impo...-of-true-wind/
"There is also another important environment
variable that greatly affects performance; current
We call Current Wiggle
the change in current
calculation with heading. Current is derived from boatspeed, heading and GPS
course/speed over ground (COG/SOG)."
Sailing in Current - Ockam Sailing Instruments
"Notice that boatspeed and heading are common to both wind and current wiggle
. Therefore, boatspeed and heading should be the first sensors to calibrate. Boatspeed is fairly straightforward; timed runs over a known distance. However compass
calibration is more involved."