Exam frequency
90%
Difficulty
3/5
Drill questions
69
Authoritative sources
Every answer on this topic traces back to the public rule corpus below.
Source excerpts
33 CFR §83.23
§ 83.23 § 83.23 Power-driven vessels underway (Rule 23). (a) A power-driven vessel underway shall exhibit: (i) A masthead light forward; (ii) A second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such light but may do so; (iii) Sidelights; and (iv) A sternlight. (b) An air-cushion vessel when operating in the non-displacement mode shall, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit an all-round flashing yellow light where it can best be seen. (c) A WIG craft only when taking off, landing and in flight near the surface shall, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit a high intensity all-round flashing red light. (d) A pow…
33 CFR §83.24
§ 83.24 § 83.24 Towing and pushing (Rule 24). (a) A power-driven vessel when towing astern shall exhibit: (i) Instead of the light prescribed either in Rule 23(a)(i) or 23(a)(ii) (§§ 83.23(a)(i) and (ii)), two masthead lights in a vertical line. When the length of the tow, measuring from the stern of the towing vessel to the after end of the tow exceeds 200 meters, three such lights in a vertical line; (ii) Sidelights; (iii) A sternlight; (iv) A towing light in a vertical line above the sternlight; and (v) When the length of the tow exceeds 200 meters, a diamond shape where it can best be seen. (b) When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power-driven vessel and exhibit the lights prescribed in Rule 2…
33 CFR §84.02
§ 84.02 § 84.02 Vertical positioning and spacing of lights. (a) On a power-driven vessel of 20 meters or more in length the masthead lights shall be placed as follows: (i) The forward masthead light, or if only one masthead light is carried, then that light, at a height above the hull of not less than 5 meters, and, if the breadth of the vessel exceeds 5 meters, then at a height above the hull not less than such breadth, so however that the light need not be placed at a greater height above the hull than 8 meters. (ii) When two masthead lights are carried the after one shall be at least 2 meters vertically higher than the forward one. (b) The vertical separation of the masthead lights of power-driven vessels shall be such that in all normal conditions of trim the after light will be se…
COLREGs Rule 22
COLREGs 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 meters 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 meters or more in length but less than 50 meters in length: − a masthead light, 5 miles; except that where the length of the vessel is less than 20 meters, 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 meters in length: − a masth…
COLREGs Rule 23
COLREGs Rule 23 — Power-driven Vessels Underway (a) A power-driven vessel underway shall exhibit: (i) a masthead light forward; (ii) a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such light but may do so; (iii) sidelights; and (iv) a sternlight. Power-driven vessel underway. Same for Inland. Relationship to the Inland Rules: Inland Rule 23 differs from this rule — compare against 33 CFR 83.23 before answering a question that turns on which set applies.
COLREGs Rule 24
COLREGs Rule 24 — Towing and Pushing (a) A power-driven vessel when towing shall exhibit: (i) instead of the light prescribed in Rule 23(a)(i) or (a)(ii), two masthead lights in a vertical line. When the length of the tow, measuring from the stern of the towing vessel to the after end of the tow exceeds 200 meters, three such lights in a vertical line; (ii) sidelights; (iii) a sternlight; (iv) a towing light in a vertical line above the sternlight; and (v) when the length of the tow exceeds 200 meters, a diamond shape where it can best be seen. Power-driven vessel towing astern - towing vessel less than 50 meters in length; length of tow exceeds 200 meters. Same for Inland Relationship to the Inland Rules: Inland Rule 24 differs from this rule — compare against 33 CFR 83.24 before answe…
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Two masthead lights are prescribed for a power-driven vessel of 30 meters in length. What is the minimum required horizontal distance between those two masthead lights?
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