140 seamanship secrets
the green “go-light,” and you are the stand-on vessel. If a vessel crosses from
right to left , you’d see the red “stop light,” and you are the give-way vessel.
E.A.S.A. solution: Slow or stop. Th is applies if you are the give-way vessel.
It also applies if you are the stand-on vessel and the other vessel isn’t giving way.
In any case, shoot drift bearings until you are clear.
Being Overtaken by Another Vessel
It’s alarming to glance astern and see a fast-moving powerboat or ship barrel-
ing toward you. In overtaking situations, relative speed is the diff erence between
speeds. Determine bearing drift right away.
E.A.S.A. solution: As long as bearing drift has a high rate of change, maintain
course and speed. If a collision appears imminent, change course 90 degrees.
Shoot drift bearings until the danger passes.
How to Cross behind a Stern-Towing Tug
First you sight the tug, then you sight the tow; once you’ve sighted both
sterns, then it’s safe to go.Lights describe a vessel’s type, size, direction of travel, and nature of work or
casualty. Towing vessels and their tows carry special light combinations, specifi ed
under Rule 24, Lights and Shapes. Th e drawings do not show the cluster of deck
lights we oft en see on these workhorses. Use binoculars to pick out a towboat’s
navigation lights.
Lights tell the size and direction of travel of a power-driven vessel. Side-
lights and stern light help defi ne the heading of the vessel. Masthead lights tell
us that the vessel is operating an engine. A power-driver vessel (PDV) less than
50 meters (164 feet) in length must show sidelights (green on starboard, red on
port), a stern light, and a single (white) masthead light. A PDV over 50 meters
adds a second masthead light aft of and higher than the forward light.
Tugs towing astern (hawser towing). Stern-towing tugs add lights above the
masthead and stern lights to indicate that they are engaged in towing. Two white
lights in a vertical line indicate a hawser (stern towline) with a length less than
200 meters (656 feet). Th ree white masthead lights in a vertical line show that the
hawser exceeds 200 meters. Oceangoing tug hawsers may extend a quarter mile or
more astern to ease tow loads. Most of the hawser lies beneath the surface, invisible
to the eye or radar. Stern-towing tugs also carry a yellow light over the white stern
light. Treat any yellow light on another vessel with caution. Use this mnemonic:
“Yellow over white, my hawser is tight.”
Barges or vessels being towed astern. Vessels being towed show a sidelight
on each forward corner and a single stern light aft. They never show masthead
lights, because they’re not propelling themselves with an engine.