Regatta pro1.1 - Google Play

Sailing android
Regatta Tactic Compass displays the relevant information that helps you to optimize the sailing route to the target waypoint.
The following information are provided in a glance:
- target waypoint bearing (orange point)
- target waypoint air distance (orange number on top right)
- real boat speed (red number on top right)
- real wind direction (blue arrow)
- layline position (green line)
- distance to layline (red number on top left)
- distance along layline (green number)
- total distance to target waypoint (red number on bottom= distance to layline + distance along layline)
- effective speed to target (red number on bottom)
- polar diagram of effective speed
All you have to do is to insert the waypoint position and wind direction then Regatta will display the route to target with layline and polar diagram of effective boat speed.
The polar diagram is not the usual polar diagram that is a boat intrinsic. The effective speed is the airline distance to target divided by the estimated time to target, given the current route going to layline and then to target along the layline. The effective speed is an index of effectiveness of route and varies with the route angle. The polar diagram shows you which is the route angle that optimizes the time to target and compares effective speeds for different angles.
There are many ways to insert waypoints. You can do it manually or using a map or using Regatta as a bearing compass.
You can find more info here:
http://www.embedia.it/files/regatta/man_en_1_0.pdf.
Please consider trying the free demo version Regatta basic.