12 July 2005

Ultimate SailingUltimate SailingStephen Bourn

www.wingbornehydrofoil.com

Apparent windangle 30 True

course

True wind

Apparentwind

Boat velocityVelocity triangle

Gravity force

– apparent wind angle

H - hydro drag angle

H - hydro elevation angle

A - aero drag angle

A - aero elevationangle

Aero force

Hydro force

Air velocity

Water velocity

True wind velocity

IH – projectedhydro drag angle

IA – projectedaero drag angle

A

A

HH

H

H

A

A

cos

sinarcsin

cos

sinarcsin

– true course

H

H

A

A

cos

sinarcsin

cos

sinarcsinmin

speedmax