I have used mine on the water, 15 races so far, its a good unit.
After removing the foam that dislodges the batteries when the back is screwed on tight ( as per instructions on the velocitek website ) the batteries now bounce out of place on waves and the unit resets, its a bit annoying. Tried diferent foam thicknesses to hold batteries but have found taping the batteries in place is the best way. A bit dodgy for an expensive gps. Velocitek dont respond to emails so debugging these units is up to the purchaser.

Darryn