Most modern boaters know GPS as being one function in a multifunction display or a fishfinder. Long before there were touchscreen displays that can control almost anything on a boat, there were portable and installed Global Positioning System units that captains used to navigate and keep an eye on their location in the middle of the ocean.
Today, there are still standalone GPS units that a boater can buy and they supply more information than most people realize. You just need to know where to look.
“If you’re a veteran cruiser, you used the standalone GPS to plot a course and then navigate from there, whereas nowadays everyone would just do it on a multifunction display,” said Peter Kinney, a technician at Alcom Marine Electronics in Costa Mesa, CA.
Many electronics suppliers still sell standalone GPS units, including Garmin, Furuno, Raymarine, B&G and SIMRAD. Boaters can also purchase handheld GPS appliances for a few hundred dollars.
The Global Positioning System (GPS) lets a boater find him or herself anywhere in the world with precision. GPS is a satellite-based navigation system that provides accurate position fixes 24 hours a day on land, sea and air in any weather with no subscription or fee.
The constellation consists of 32 satellites in Medium Earth Orbit (MEO) 12,550 miles above the Earth. Using timing signals sent by the satellites and knowing the exact orbital locations of the satellites, a GPS receiver can determine your location accurately within 18 feet and your altitude within approximately 30 feet.
Just because they would be considered simplified compared to multifunction displays or chartplotters doesn’t mean that fixed and handheld GPS receivers don’t have some hidden benefits of which many boaters aren’t aware.
For larger, long-range boats like trawlers and sailboats, Kinney explains that a dedicated GPS unit on its own network is a good idea because it provides a constant position on a screen. The common electrical network on modern boats is called NMEA 2000, which provides many conveniences because so many appliances tie into it as the “backbone” of a boat’s onboard systems. Old-school GPS units are installed on what’s known as the NMEA 0183 network. Because it’s not linked with other pieces of equipment, a malfunction with a different accessory can’t take down the whole system.
One example of the hidden features in a standalone GPS unit is that an antenna installed on a NMEA 2000 network can broadcast things like heading, course, speed over ground, course over ground and more, to other linked equipment. You can use the GPS like a multifunction display without having to spend thousands of dollars for the more complicated appliance. Some antennas even have a built-in compass that will give data like heel angle, pitch, rate of turn and more.
“It can act like an MFD because you are connected to a network,” said Kinney. “If you don’t have an MFD, you can use a GPS-like one.”
Another useful GPS feature is the ability to set an “anchor alarm.” It lets you establish a geofence around your boat while it’s at anchor. If the anchor drags or the line comes loose and your boat goes through the geofence, your GPS will sound an alarm.
Some of today’s systems also let you interface with your boat’s GPS from afar via a smartphone app so it acts as a security system. Set up the geofence around your boat, and if it moves outside the perimeter, you’ll get a text alarm as soon as it moves out of position.
If a GPS receiver is networked with other electronics aboard the boat, it can tell an autopilot where to steer and overlay additional data (like boat radar) over the digital charts.
Some other uses for GPS receivers can be to providing detailed diagnostics for compass accuracy, the ability to overlay radar onto charts, support network connectivity, and offer special functions for fishing positioning.
Fixed or Handheld
For years, boaters had a choice between handheld GPS units and permanently installed units usually found at the helm of most runabouts’ center consoles.
“If you’re going 100 miles out to fish, I would rather have something fixed on the boat,” said Kinney. On the other hand, if you are just heading out to Catalina Island and have a waypoint programmed into a handheld unit, you can navigate right to your desired location.
Because of their compact, portable design, handheld GPS devices are good for kayaks, paddleboards, sailing dinghies and other small boats. They have their own power source, a small display screen and an internal antenna. Some people would argue that a cell-phone app does the same thing, but the batteries in a GPS aren’t being used to power other apps that will most likely drain a smart phone’s power source more quickly.
Some handheld/portable GPS receivers can be mounted in a bracket on the dashboard of a boat. Many come with a power cord and rechargeable batteries. The most sophisticated versions have touchscreen capability.
Fixed-mount displays are designed to be installed at a boat’s helm and are made to withstand the elements. Many feature full cartographic coverage of U.S. waterways and you can purchase additional cards for inland lakes. Fixed-mount displays don’t draw much power at all, so that shouldn’t even be a concern. To stay current with updates made to charts, it’s a good idea to update GPS software and maps at least every year. New software can cure bugs, add upgraded feathers and, for anglers, update no-fishing zones.
Most fixed-mount and handheld GPS receivers have the Automatic Identification System integrated into them. Every vessel that has AIS technology will show up on the GPS unit’s screen to improve the operator’s situational awareness.
When you’re underway, your GPS continually updates your position and provides speed and directional data. The more satellite signals your GPS receives, the more accurately it can calculate information and can usually put your position within a 16-foot radius. Higher-end models with dual channels get much closer.
The most popular GPS function for many boaters is storing waypoints. It lets an operator permanently record the location of a channel, shoal or favorite fishing spot. String together the waypoints to create a route that takes you from point A to point Z.
In recent years, digital charts have become more comprehensive with improved details and better accuracy, leading to the increase in devices called chartplotters that integrate GPS into them and let a captain tap two spots on a screen to create a course. Some also match GPS with depth soundings taken from a fishfinder.
As with any technology, make sure you can perform basic navigation functions to get home if your GPS malfunctions or shuts down. Know how to read a paper chart and how to use a compass if you need them to get home.
