A Close Encounter
It’s after dark off Delaware Bay. It’s choppy and drizzling out. My boat is on a northerly heading, sailing close-hauled in a brisk northeast wind. Since visibility has been poor all day, I’ve been keeping a radar watch. I’ve turned on the FTC, or rain clutter control, to suppress the reflected echoes from the rain, making sure not to turn it too high. I’ve also turned on the STC, or sea clutter control, to suppress echoes from the chop, and I’ve set up a 360-degree guard zone at eight nautical miles around the boat. The radar’s transmitting range is also set to eight miles.
As part of my watch routine, I periodically decrease the radar’s range to take a closer look for anything that might be near the boat. I then increase the range out to 16 miles to get the widest view possible.
Suddenly, the guard alarm sounds. Sure enough, a dark splotch appears on the outer range ring on the radar screen about 45 degrees off my starboard bow. Soon it’s clear the target is heading in my direction. I’ve got the echo trails feature on. The angle of the trail behind the target on the screen, the steadily decreasing range, and constant relative bearing all suggest we’re on a collision course.
I now activate the electronic bearing line feature and bisect the target with the EBL. The target bearing appears at the bottom of the screen. I can estimate the range from the range rings, but I want more precise information, so I press the VRM button and move the variable range marker onto the target’s inner edge. Now I’ve got much more exact range and bearing data. It takes the target 10 minutes to travel three nautical miles, so its speed is about 18 knots. The current range is now six nautical miles, so it’s about 20 minutes away.
The target’s bearing remains constant and the range continues to decrease. If I had one of those new units that overlays radar images on electronic charts, I could see at a glance which new courses will keep me clear of all navigation hazards. I make a mental note to consider upgrading.
I decide to slow down and let the target cross my bow. I spill some air from my headsail to decrease speed. A few minutes later, a container ship crosses my bow about two miles out. Knowing how to use radar has made a stressful situation more routine and manageable.