Night and Day
We were heading 30 miles offshore in the pre-dawn darkness, and obstacles lay ahead. Scores of lobster-pot buoys bobbed just outside the inlet. The buoys didn’t show up on radar, and a spotlight proved more blinding than beneficial.
The best solution came in the form of my FLIR Ocean Scout 320 handheld thermal imaging scope. It allowed us to clearly see each buoy and weave our way through propeller-entangling lines. “This is just one advantage of marine thermal imaging systems,” says Lou Rota, vice president of worldwide sales for FLIR Marine. “Not only does thermal imaging enhance navigational safety at night, many anglers use thermal imaging to find fish.” Thermal imaging systems detect infrared radiation, which is invisible to the human eye. Technologies from companies such as FLIR and Iris convert infrared to an image on a display that you can see. “These systems detect minute differences in the thermal signatures of objects to thousandths of a degree,” says Tony Digweed, head of North American operations for Iris. Since thermal imaging measures relative heat, an object need not be extraordinarily warm to show up. Whether you choose a handheld scope or an installed model that displays on your MFD, here are some of the benefits thermal imaging affords:
Negotiate Narrow Channels
On a recent trip to Grand Cayman, I joined Capt. Alex Laing aboard his Jupiter 34. Our midnight departure took us through a narrow mangrove- lined canal, then along a serpentine channel marked by makeshift, hard-to-see PVC pipes, and across a shallow, reef-strewn bay. Laing effectively used the FLIR MD-324 mounted on the hardtop, which displayed through an MFD at the helm, to navigate until we reached the open water of the Caribbean. Then he set a course for our fishing spot 110 nautical miles to the west. “We often leave well before daylight when fishing these offshore banks, and I rely heavily on the FLIR system for finding my way through tight channels and harbors,” Laing says.
Ocean Scout Series
Scan for Obstructions
Many times, low-lying objects don’t reveal themselves on radar, and this is where thermal imaging systems offer one of the greatest advantages. “You might not see a floating log, pallet, crab-pot buoy or submerged shipping container on radar,” Rota points out. “Yet these objects will show up clearly on a thermal imaging system.”
Among these obstructions are whales that linger at the surface at night. Thermal imaging detects the spouts of these animals, which often congregate in productive offshore areas. Striking a whale can result in major damage to your vessel, and injury to crew members as well as the animal. “Many commercial vessels are now equipped with FLIR systems to help them see whales so they can slow down and maneuver to avoid them,” Rota says.
Peace of Mind
“Thermal imaging is a huge stress reliever,” Rota says. “It can make the captain more comfortable while navigating in the black of night.” While prudent seamanship dictates maintaining a safe speed, especially when visibility is limited, thermal imaging in some cases might allow the helmsman to step up the cruising speed from, for example, 6 knots to 12 knots. That means getting to the fishing grounds in half the time. Thermal imaging also puts crew members at ease. During a recent trip offshore on an inky, moonless night, for instance, the lack of visibility pushed one of my guests to the verge of an anxiety attack. To allay his fear, I handed him my handheld thermal imaging scope and instructed him to scan the water ahead and sing out if he spotted anything. His anxiety soon melted away. “The brain plays tricks when you can’t see the waves or the horizon,” Digweed says. Thermal imaging helps eliminate that feeling of disorientation and enhances situational awareness.
Find Floating Structure
This technology also helps you find floating structure, including sargassum rafts and floating kelp paddies, at night. “Thermal imaging definitely helps you see weed lines and kelp paddies,” Rota says. Such floating vegetation possesses completely different heat characteristics than the surrounding water, and, though these differences are minute, thermal imaging detects them. Offshore anglers in Southern California no longer need to wait until daylight to start hunting for kelp paddies. They can even start fishing around them in the dark. During daylight hours, thermal imaging also helps to locate patches of weeds and paddies, especially when there’s a lot of glare or heavy overcast that makes it more difficult to see them in choppy seas.
Thermal imaging cameras are also sensitive enough to see temperature breaks, which are areas that attract schools of baitfish and predators, says Digweed. As long as the water temperature changes rapidly within a few meters, thermal imaging can detect the difference. “In fact, thermal imaging technology is so sensitive, it can see the temperature difference between the top and bottom of a wave,” Digweed says.
Fish at the Surface
Thermal cameras also see fish at night. “A lot people are saying they’ve hooked tuna after finding breaking fish before daylight using thermal imaging ,” Rota says. “Many also tell us they spot baitfish dimpling the surface in the dark. “Schools of fish change the water surface, and that’s what you can see with thermal imaging,” Rota explains.
Most boating anglers use an installed camera, such as a FLIR MD- or M-Series, for spotting fish on the surface. “With the FLIR systems, the best setting for this purpose is Night Running with the image format set to Black Hot,” Rota advises. Black Hot shows warmer objects in darker shades versus the traditional White Hot thermal image, which turns warmer objects a lighter shade. Thermal imaging technology is growing in popularity and, one day, might become as common as marine radar. As more captains discover that thermal imaging can help them find fish as well as navigate safely, that day may come sooner rather than later.