Use Your Radar to Find Fish from Afar



Lowrance 4G Radar

Lowrance 4G Radar

Radar is one the great innovations of the 20th century. Starting back in World War II locating German U-Boats, shipping and aircraft it is now a standard feature on most Sportfishing boats.

While most anglers think of marine radar as a tool to help with navigation in cases of low visibility it is also a great tool to help locate fish beyond your visual range. Let’s look at some examples of how to use radar to up your fish catch.

Find the charter fleet

The advantage of radar when fishing the WA coast at Westport became abundantly clear to me why using it to find the charter fleet putting more fish in my boat. Whether I was just prospecting for salmon or running 50 miles offshore for tuna fishing with radar is a key tool in my arsenal. This summer I was having a slow morning and only had a single king in the boat. I checked my Lowrance Broad Band 4G Radar zoomed out from my normal 1 mile range used for running in the fog out to 8 miles. I was quickly rewarded by seeing the clear red blobs of 7 vessels on the radar screen. Their lack of movement indicated that they were on fish. I made the run to the boats and ended up limiting on chinook with some of the Westport charter fleet. Without radar I would have never discovered this spot that day or even ventured out in the limited visibility on the ocean that day.  I used the Electronic Bearing Line (EBL) feature to determine a course to the fleet, and the Variable Range Marker (VRM) to confirm the distance to the fleet before making the run.

Keeping Tabs

Radar lets you find and follow the offshore fishing boats in other ways too. Miniature Automatic Radar Plotting Aid (MARPA) tracks targets. MARPA allows you to automatically track the course and speed of a number of targets, up to 10 on a Broadband radar so you know exactly where they are and where they are heading. MARPA was designed to help avoid collisions in limited visibility, these features also tell you if a boat is trolling or running at speed and if it suddenly stops while trolling a good indication they just hooked up. This can be very usefully information that can lead you to very productive fishing areas.


Radar overlay

Radar overlay


A radar/chart-plotter overlay serves as another tool in your angling tool box. This feature places a live radar image on top of an electronic chart. The returns are semitransparent so you can also see the chart features, land mass and bottom contours under the radar image. This is how I run my Lowrance HDS Touch on the GPS screen. One way I have used this feature is to look at the bottom area on a chart to see what the other boats are fishing on. Maybe a bottom fish hole or a known salmon fishing area. To make this feature work you will need to add an electronic compass so the radar knows what direction the boat is pointed to be able to overlay the radar on the chart. This can be done installing an external GPS antenna with a heading sensor like a Point 1 Module. The other way to get the boat heading is from a Flux Gate Compass generally used on an autopilot system. On my boat I use a Navico RC-42 fluxgate compass to drive my Simard AP-28 Autopilot and it also provides me the ability to overlay radar on my GPS screen.



It’s no secret among savvy NW anglers that you can use radar to find a flocks of feeding birds at a distance with marine radar. Finding feeding birds often means locating a school of feeding fish. You can pick up bird flocks with any radar, even low-power dome models as well as the open-array models. It does take some practice to tune a radar to recognize the signals that birds represent on the screen. You will need to turn up the sensitivity/gain until the screen fills with clutter, and then dial it down about 2-3 percent. The best way to practice this is on flat water at closer ranges to see what the bird images look like on your radar. The distance you can see birds at is limited by the type of antenna you have. On dome radars you might get up to 5 miles in good weather conditions. On the higher power open-antennas you can see birds up to 8-10 miles depending on how high your antenna is mounted off the water.


The same radar that helped the allies win WWII can now help you score more fish. Give it try.


Capt John Keizer

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