Page 210 - NAVAL SCIENCE 3 TEXTBOOK

216 NAVAL SKILLS

Special Rules for Naval Vessels Connlsion over whistle signals is probabl)1 responsible for more
collisions than an)' other part of the rules of the road. Though all
ivlany naval vessels. because of their special construction. cannot
the rules are important, the steering and sailing rules arc the ones
comply exactly with the rules for running lights. In such cases, the
most essential to avoiding collision. The rules are design cd to keep
vessels must meet the requirements of the rules as nearly as possi-
vessels clear of one anothcr.
ble. Any departures from the rules of the road for naval vessels are
provided for by U.S. law.
Some examples of these variations arc the following: Risk of Collision
The horizontal separation of the white lights all destro)'ers Both international and inland rules govern situations in which
and sl1laller ships is oftcnless than that required by the rules. two vessels are approaching each other with the risk of collision.
The white lights on aircraft carriers are usually on the super- There are three basic approach situations: meeting, overtaking,
structure and off the centerline. and crossing. The situation depcnds upon the relative position of
the two vessels whcn they first sight each other.
Special lights such as speed lights, carrier lauding lights, and
colored recognition lights may be shown all naval vessels dur- Vessels do not need to maneuver if they will pass clear by sim-
ply maintaining their courses and speeds. But when two ships or
ing certain operations.
boats approach each other and there is a risk of collision, at least
During certain exercises, naval vessels may show no lights at
one must keep Ollt of the way of the other. This may be done by
all. In peacetime. however, the officer in tactical command will
aitering course or by slowing, stopping, or backing engines. The
usually order navigation lights turned on if a merchant ship
vessel that must keep out of the way of the other is called the give-
approaches the formation. Departure frOI11 the rules of the
IVn)' vessel. The other ship is required to maintain course and
road for exercises is not a good idea if it could result in tl colli-
speed, and is caHed the stn1,d-01' vessel.
sion with a merchant vessel.
The 1'llles sa)' that risk of collision can be determined by care-
Specitlilights and day shapes are required for minesweepers fully watching the compass bearing of all approaching vessel. If the
when the)' arc engaged in sweeping operations. bearing does not appreciably change as the rangedecreases,sllch risk
U.S. submarines are specially authorized to display an amber- should be considered to exist. Therefore. when in a constant bear-
colored intermittent flashing beacon-three seconds on, three ing decreasing range situation, the vessel is said to be on a "collision
seconds off- when running surfaced, in addition to other course." There is a saying among mariners: "A collision at sea can
required lights. ruin your whole day." There is no mariner who does not take the
possibility of collision vcr)' seriously.
Whistle Signals

\"'histle signals are required by both sets of rules for vessels maneu-
vering within sight of one another. Under inland rules,a whistle is a
signal of il/tel/t, sounded before any maneuvers arc made. The ves-
sel that sounds a signal in inland waters does not execute a maneu-
ver until the other vessel makes the same signal in reply, meaning
that it understands and agrees. If the other vessel does not under-
stand the signal, or considers the proposed maneuver dangerolls,
it replies with the danger signal. a signal consisting of not less than
fil'e short, rapid blasts.
\,\I]listlc signals in international waters are signals of executioll,
sounded when a vessel is starting a maneuver. No replies are neces-
sary. Since international waters are not as crowded ilS inland waters.
international rules for whistle signals are not as demanding as inland
rules. \-"histle signals are absolutely essential to safe navigation, how-
ever. The principal international whistle signals are the foUowing:

One short blast: I am altering rny course to starboard.
Two short blasts: I am altering nly course to port. Typical meeting, crossing, and overtaking situations as viewed by
Three short blasts: My engines are going astern. own ship.
Five or more short blasts: Danger signal.