NOW YOU’RE Seeing THINGS
Early January isn’t Puget Sound’s sweet spot, but when one is beholden to invitations to sail on other people’s boats, sometimes there’s no choice but to pack a few extra layers, a positive attitude, a piping-hot thermos and maybe something a little stiffer for après-sail time. So when an offer came to join some friends for an all-day outing that would involve a post-nightfall return (read: anytime after 1615 hours at 48 degrees north) to Seattle’s Shilshole Bay Marina, I packed my warmest gear and two FLIR handheld thermal-imaging cameras that I was testing, and I did my best to hoodwink myself into believing it wasn’t 27 degrees when we departed.
Flash-forward 12 frigidbut-fun hours and the sun had slipped below the Olympic Mountains as we were searching for a channel marker. I grabbed FLIR’S Ocean Scout 640 from my sea bag and, after adjusting color palettes, found the buoy just as things were getting frosty. Instantly, the mood thawed and conversation quickly pivoted to dinner, and a nip of Caribbean rum.
The desire to peer through the murk is as aged as the ancient mariner himself, and we modern cruisers are fortunate to live in times when off-the-shelf technology can significantly reduce the stress of nighttime navigation. While thermal-imaging cameras have historically been expensive, this equipment affords a huge amount of safety and situational awareness, both during daylight hours and on the graveyard watch.
Better still, prices are dropping. Here’s a look at how this technology works, and some observations gathered while field-testing three currentgeneration handheld devices.
Heat of the Moment Thermal-imaging cameras sense minute temperature differences (read: thermal radiation) between objects and their backgrounds that are warmer than absolute zero (a balmy minus-459.67 degrees Fahrenheit). The cameras’ microbolometer sensors use what they capture to render video imagery.
For example, FLIR’S thermal-imaging cameras use microbolometers that are sensitive to 50 millikelvins, or one-twentieth degree Celsius, to create real-time video imagery, which is streamed to an integrated or networked display, requiring little user input. Much like digital cameras, thermal-image cameras come with different pixel densities; higher densities equate to higher-resolution imagery and better digital-zoom functionality (more on this later).
Most thermal-imaging cameras offer different color palettes (i.e., the set of colors that are used to render an image), which allow the users to tailor the imaging to different situations. When the right color palette is matched with the right atmospheric and viewing conditions, these palettes highlight areas of contrast. For example, FLIR’S Ocean Scout 640 handheld camera comes with three palettes, White Hot, Black Hot and Instalert. “White Hot, where the hottest temperatures are white, looks best and interprets best at night,” says Jim Mcgowan, FLIR’S Americas marketing manager. “During the day, I like to flip to Black Hot, which is crisper when things warm up. And if you’re looking for crew overboard, Instalert turns them red.”
Today’s manufacturers offer a wide variety of cameras, starting with handheld models that range from $600 to $7,000, all the way up to fixed-mount devices that can run anywhere from $2,500 to $85,000-plus.
Fixed-mount thermalimaging cameras are fitted inside small domes that network with chart plotters or dedicated screens to display their imagery. These cameras are typically weatherproof, require little maintenance and
Iris Innovations’ color palettes let you adjust to conditions: Black Hot’s good for daytime (top left); White Hot works well at night (above). Red Hot (top right) is useful in emergencies.