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The
famously thick fog in my Maine home waters is the classroom for many tutorials
in marine safety. I’ve lived my share of those lessons, and one
even left me grinning. On that particular August afternoon, I was at the
wheel of an unfamiliar but well-equipped and lovely 50-foot schooner,
bound from Camden with a party of inexperienced sailors. The boat’s
radar was inconveniently far below at the nav station, but I’d had
a peek before we slipped into the pea soup and knew that a number of vessels
were gathered around the entrance bell buoy. It was nearly calm, and folks
in these waters tend to take it slow and careful, so I wasn’t overly
anxious.
I did,
however, engage the boat’s foghorn. It was an unusually large model
driven by compressed air, and darn if it didn’t emit a powerful
“blooooooooooonk” that made us sound like a tramp steamer.
And darn if our unseen neighbors didn’t whip into action. We could
hear powerboats clink into neutral and winches grind as sailboats changed
course. The fleet parted before us like the sea before Moses. I quite
liked that, and have henceforth valued the concept of sounding (and looking)
large.
The
lesson is relevant to the more dangerous world of passagemaking. If you
are in the vicinity of big ships traveling at speed in dark or fog, a
big horn is not going to cut it. What you want is to paint a significant
target on everyone’s radar screens, and the sooner the better. When
delivering yachts, I spent many a nervous watch passing through shipping
lanes and amongst fishing fleets, wondering just how good a radar signature
I was making. Sometimes I asked other vessels, and the results weren’t
always encouraging.
Wooden
and fiberglass sailboats know they have a radar problem, and most are
equipped with one of the various passive reflectors, which are essentially
geometric shapes that put as many perpendicular metal surfaces around
the horizon as possible. Unfortunately, they don’t work very well,
as was thoroughly documented by a U.S. Sailing Association testing program
several years ago. Powerboaters tend to think that their vessels are substantial
enough to reflect back a reasonable amount of radar pings, and often they’re
right; a lot of vessels sport enough metal hardware and internal machinery
to do a fair job. There’s also the half-truth that if you are running
a radar yourself it will generate a signature. The whole truth is that
sometimes one radar will pick up interference from another’s pulse;
but a radar’s interference rejection (IR) filters remove that interference,
and most operators use IR in busy traffic.
Times
are also changing. Boats and ships are faster, and there are more of them
out there. Bridges are more lightly manned making the use of radar more
critical for collision avoidance. Modern automated radar tracking usually
won’t lock onto a target unless it appears in at least half its
sweeps. The bottom line: I’m not satisfied to even look my size
when in traffic with ships that are galloping elephants compared to my
50-foot mouse. Humble as I fancy myself, I want to swagger onto the radar
screen of a ULCC (ultra large crude carrier).
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Radar Reflector continued > Page 1, 2
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