I didn't imagine SailFreeGPS could be used for so long time !!!I used it the other day on a quick 2 day trip.
The graph is very small and hard to see. To expand it one needs to drop the time from 20 minutes to lower. It would be nice to spread it with fingers.
20 minutes is long enough for tracking but not long for currents on a 2 day trip. It would be nicer if it was 24 hours.
I just imaged it could be used to help to trim the sails ...