The complete Livorsi GPS kit includes the gauge, receiver antenna, and recall switch

Since the early days of recreational boating, speed measuring devices have never enjoyed the instant accuracy of their automotive counterparts. That’s for obvious reasons, since a watercraft does not have predictable traction to the ground like a land-based vehicle does. For that reason, speed was measured by the marginally accurate method of measuring water pressure. Thankfully, those days are over, and the buzzword of the 1990s became the GPS, which stands for Global Positioning System.

The GPS changed the way speed was measured on the water. While radar systems have been out for decades and still remain a standard for measuring the speed of any vehicle, even the handheld radar units are quite expensive. Further, a radar unit is not an in-the-vehicle solution, so boaters were left to contend with pitot pickups and paddle wheel mechanical speed senders.

The standard GPS measures location speed by tracking satellites in Earth’s orbit and calculating their distance relative to the GPS receiver. A GPS unit measures this speed by triangulation, meaning that a minimum of three satellites must be tracked to return an accurate calculation.

Left to right:  1. Rear view of GPS gauge.  2. Livorsi high-gain receiver antenna.  3. Heavy duty recall switch with rubber switch boot and faceplate.  4. Detail of recall switch.

For this article, we’ll be installing the Livorsi Marine 120 MPH dedicated GPS speedometer with top-speed recall. The unit includes a high gain, 12 channel receiver that is accurate within one MPH.  The handy memory recall function displays the top speed achieved by actuating a toggle switch. Additionally, the Livorsi GPS system is compatible with handheld units that have data output capability, if you choose not to use the Livorsi receiver antenna. This unit is also available in 80, 100, 120, 140, 160, and 180 MPH versions, as well as analog and digital readouts in a variety of colors and styles. Completing the Livorsi GPS speedometer lineup is a special 52 MPH version for ski applications.  The GPS Ski is available as a gauge only, or as a complete kit.

The Livorsi GPS gauge is a fully marinized, high quality unit that is very accurate and available in many speed ranges.

If your boat is like most, it already has a traditional mechanical water pressure speedometer. In that case, you’ll surely want to replace it with a GPS unit for two reasons: first, the GPS unit much more accurate and provides an electronic recall of top speed, and second, the water pickup tube in mechanical speedometers (also known as the pitot) can actually slow your boat down or affect its performance

The installation is fairly straightforward. The gauge is installed like any other gauge, with the addition of the GPS receiver antenna and recall switch. No special tools are required, but placement of the GPS receiver antenna is important. While most handheld units will not function under the deck of a boat or beneath any obstruction to the sky, the Livorsi unit can in most cases, however you should test the location you wish to mount the antenna before making it permanent.

Page Two: Installation and evaluation