Anyone ever used a bicycle GPS speedometer on their boat? Have been wanting to install a speedo of some sort. Looking at the cost, the standard sensor in the water type seem to be rather expensive, and somewhat questionable accuracy. So that got me thinking. The automotive after market speedos have turned to GPS, so in doing a little search, I've discovered that there is a number of bicycle GPS speedometers that are rather inexpensive. Many of these speedos have a homing feature, where it will give you an arrow direction and distance from a preset waypoint. That also seemed desirable in that on occasion I have sailed at night, and it can be difficult to find the port. (inland lake - beaching the boat on the campground shore). So it seems like one of these bicycle speedos could be the cats meow for sailing, except that it reads in MPH rather than knots, which is not all bad anyway. So is anyone using one, and have they found any one particular brand more useful than anything else?