We've been promised a SPOT for review, and will provide a more detailed review after thorough testing. Browsing the Internet, we found some very good user reviews that include some cautionary reports. It appears as though the GPS chipset isn't as good as some available on newer GPS units, which means the unit can have trouble obtaining signals from the GPS system in anything but a perfect environment. According to reviewers, SPOT has difficulties getting signals in urban areas, places where there are trees overhead, in a car, or in a backpack. In short, SPOT has to have a very clear view of the sky, which means it should work well on the water. There's also no way of determining if your signal, distress or otherwise, has been received, as SPOT is strictly a one-way device.