A waypoint is the same as a mark. It does not move with the current.
Using only the speed through the water a cross set with a couple of knot
drift in light wind can create a huge error.
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com
Works OK for me since I use waypoints 20 to 50 miles apart instead of