22.24 Towing and pushing

(1) When towing, a power-driven vessel must exhibit—

(a) instead of either of the masthead lights prescribed in rule 22.23(1)(a) and (b), two masthead lights in a vertical line,

EXCEPT that when the length of tow exceeds 200 metres measured from the stern of the towing vessel to the after end of the tow, 3 such lights in a vertical line must be carried; and

(b) sidelights; and

(c) a sternlight; and

(d) a towing light in a vertical line above the sternlight; and

(e) when the length of tow exceeds 200 metres, a black diamond shape where it can best be seen; and

(f) if the towing operation is such that it severely restricts the towing vessel and its tow in their ability to deviate from their course, in addition—

(i) three all-round lights in a vertical line where they can best be seen the highest and lowest being red and the middle one white; and

(ii) three black shapes in a vertical line where they can best be seen the highest and lowest being balls and the middle one a diamond. (rule 22.27(3)).

(2) When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit, they will be regarded as a power-driven vessel and must exhibit the lights prescribed in rule 22.23 for such vessels.

(3) A power-driven vessel when pushing ahead or towing alongside, other than a composite unit must exhibit—

(a) instead of either of the masthead lights prescribed in rule 22.23(1)(a) and (b), two masthead lights in a vertical line; and

(b) sidelights; and

(c) a sternlight; and

(d) if the towing operation is such that it severely restricts the towing vessel and its tow in their ability to deviate from their course, in addition—

(i) three all-round lights in a vertical line where they can best be seen the highest and lowest being red and the middle one white;

(ii) three black shapes in a vertical line where they can best be seen the highest and lowest being balls and the middle one a diamond (rule 22.27(3)).

(4) A vessel or object being towed, other than an inconspicuous, partly submerged vessel or object, or combination of such vessels or objects, must exhibit—

(a) sidelights; and

(b) a sternlight; and

(c) when the length of tow exceeds 200 metres, a black diamond shape where it can best be seen.

Where from any sufficient cause it is impracticable for a vessel or object being towed to exhibit the lights or shapes prescribed, all possible measures must be taken to light the tow or at least to indicate its presence.

(5) Any number of vessels being towed alongside or pushed in a group must be lighted as one vessel and—

(a) a vessel being pushed ahead, not being part of a composite unit, must exhibit sidelights at the forward end; and

(b) a vessel being towed alongside must exhibit a sternlight and, at the forward end, sidelights.

(6) An inconspicuous, partly submerged vessel or object, or combination of such vessels or objects being towed, must exhibit—

(a) if it is less that 25 metres in breadth—

(i) one all-round white light at or near the forward end except in the case of dracones, which need not exhibit a light at or near the forward end; and

(ii) one all-round white light at or near the after end; and

(b) if it is 25 metres or more in breadth, 2 additional all-round white lights at or near the extremities of its breadth; and

(c) if the length of towed object exceeds 100 metres, additional all-round white lights so that the distance between lights does not exceed 100 metres; and

(d) a black diamond at or near the aftermost extremity of the last vessel or object being towed, and if the length of tow exceeds 200 metres, an additional black diamond shape where it can best be seen, and located as far forward as practicable.

(7) If it is impracticable for a vessel or object being towed to exhibit the lights or shapes prescribed, all possible measures must be taken to light the tow or at least indicate its presence.

(8) Where from any sufficient cause it is impracticable for a vessel not normally engaged in towing operations to display the lights for a towing or pushing ahead or towing alongside vessel (rule 22.24(1) or 22.24(3)), that vessel is not required to exhibit those lights when engaged in towing another vessel in distress or otherwise in need of assistance.

All possible measures must be taken to indicate the relationship between the towing vessel and the tow as authorised in rule 22.36 “Signals to attract attention”, in particular by illuminating the tow line.