Page 165 - Collision Avoidance Rules Guide

-a sternlight, 2 miles;
-a towing light, 2 miles;
-a white, red, green or yellow all-round light, 2 miles.
(d) In inconspicuous, partly submerged vessels or objects being
towed:
-a white all-round light, 3 miles.

COMMENT:
With the amendments of 1981, paragraph (d) was added, because of
the amendments to Rule 24(g).

Visible
The definition of ‘visible’ given in Rule 1 (c)(x) of the 1960 Regulations
has not been retained in the 1972 Regulations. Paragraph 8 of Annex I
gives a formula for calculating the luminous intensity of lights which
takes account of visibility and atmospheric transmissivity.

Metrication
The lengths of 50 metres, 20 metres and 12 metres, referred to in
Rule 22, correspond to lengths of 150 feet, 65 feet and 40 feet,
respectively, used in the 1960 Regulations.
The minimum range of almost all lights for vessels over 50 metres
in length and of sidelights for power-driven vessels of 12-20 metres in
length has been increased by one mile in the 1972 Regulations. For
most other lights, including the all-round lights to be shown by ves-
sels of over 50 metres in length at anchor or on pilotage duty, the
minimum range is unchanged, but it is reduced from 3 to 2 miles in
the case of masthead lights for power driven vessels of less than 12
metres in length.

RULE 23
Po w er- dri v e n Ve s s e Is Underway

(a) A power-driven vessel underway shall exhibit:
(i) a masthead light forward;
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