Part C — Lights and shapes

COLREGs Rule 24: Towing and pushing

Rule 24 says a vessel towing shows two masthead lights in a vertical line (three if the tow is over 200 m), sidelights, a stern light and a yellow towing light above the stern light, plus a diamond shape by day if the tow is over 200 m.

What Rule 24 says

  1. Towing: two masthead lights forward in a vertical line, or three when the tow measured from the stern of the towing vessel to the after end of the tow exceeds 200 m; sidelights; a stern light; a yellow towing light above the stern light; a diamond shape where it can best be seen if the tow exceeds 200 m.
  2. A pushing vessel and the vessel pushed ahead, rigidly connected as a composite unit, are lit as a single power-driven vessel.
  3. Pushing ahead or towing alongside (not a composite unit): two masthead lights in a vertical line, sidelights and a stern light.
  4. A vessel being towed: sidelights, a stern light, and a diamond shape if the tow exceeds 200 m.
  5. Partly submerged or inconspicuous objects being towed show white all-round lights at their ends, with a diamond at the after end of a tow over 200 m.
  6. A vessel not normally engaged in towing that tows a vessel in distress need not show these lights, but must make the relationship clear, for example by lighting up the towline.

This is a plain-English summary, not the official wording. For the exact text, see the IMO convention. In UK waters the rules are given legal force by the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations.

What it means on a yacht

Two or three white masthead lights stacked vertically ahead of you at night mean a tug, and a tow far behind it. Never pass between a tug and its tow: the wire can be invisible and just under the surface.

Lights and shapes under Rule 24

  • Towing, tow under 200 m Rule 24

    Two masthead lights in a vertical line, plus a yellow towing light above the stern light. Over 200 m: three masthead lights, and a diamond by day.

  • Towing, tow over 200 m Rule 24

    Three masthead lights in a vertical line, sidelights, stern light and a yellow towing light above it. By day, a black diamond where best seen.

  • Pushing ahead or towing alongside Rule 24(c)

    Two masthead lights in a vertical line, sidelights and a stern light. No yellow towing light, because there is nothing astern of her.

  • Vessel being towed Rule 24(e)

    Sidelights and a stern light only, no masthead light. If the tow is over 200 m, a black diamond by day. Look for the tug ahead of her.

Drawn from the starboard side at night, with the day shapes below. See every aspect in the lights and shapes trainer.

Practise it

Test yourself on who gives way in the free COLREGs trainer, or print the rules of the road cheat sheets for the chart table.

Other rules in Part C