Page 164 - Collision Avoidance Rules Guide

Flashing light
The flashing light, as defined in Rule 21(f), is a new provision. It is
prescribed only for air-cushion vessels (Rule 23b). The rate of flash-
ing is higher than that previously specified for hovercraft in the
Mariner’s Handbook and Notices to Mariners. The rate was made
deliberately high to enable mariners to distinguish this light from the
flashing lights of buoys and other aids to navigation which usually do
not flash more than 60 times per minute. Submarines may also exhibit
a flashing light.

RULE 22
Visibility of Lights

The lights prescribed in these Rules shall have an intensity as
specified in Section 8 of Annex I to these Regulations so as to be
visible at the following minimum ranges:
(a) In vessels of 50 metres or more in length:
-a masthead light, 6 miles;
-a sidelight, 3 miles;
-a sternlight, 3 miles;
-a towing light, 3 miles;
-a white, red, green or yellow all-round light, 3 miles.

(b) In vessels of 12 metres or more in length but less than 50
metres in length:
-a masthead light, 5 miles; except that where the length of
the vessel is less than 20 metres, 3 miles;
-a sidelight, 2 miles;
-a sternlight, 2 miles;
-a towing light, 2 miles;
-a white, red, green or yellow all-round light, 2 miles.
(c) In vessels of less than 12 metres in length:
-a masthead light, 2 miles;
-a sidelight, 1 mile;
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