Rule 28: a vessel constrained by her draught.

What does COLREGs Rule 28 say?

A vessel constrained by her draught may, in addition to the lights of a power-driven vessel underway in Rule 23, exhibit where they can best be seen three all-round red lights in a vertical line, or a cylinder.

So at night: masthead light(s), sidelights and sternlight, plus three all-round reds in a vertical line. By day: a cylinder.

Is the Rule 28 signal compulsory?

No — the rule says 'may'. A vessel constrained by her draught that does not show the signal gets none of the protection that comes with it under Rule 18(d), because that protection is tied to exhibiting the Rule 28 signals.

What is a 'vessel constrained by her draught'?

Rule 3 defines it as a power-driven vessel which, because of her draught in relation to the available depth and width of navigable water, is severely restricted in her ability to deviate from the course she is following. Only a power-driven vessel can be one. You are far more likely to meet one — a deep-draught ship in a dredged channel or approach — than to be one.

What does Rule 18(d) say about vessels constrained by draught?

Any vessel other than one not under command or restricted in her ability to manoeuvre must, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draught that is exhibiting the Rule 28 signals. The vessel constrained by her draught, in turn, must navigate with particular caution, having full regard to her special condition.

How do I tell constrained by draught from not under command or aground?

Count the reds and look for what comes with them. Constrained by draught: three all-round reds in a vertical line, with the lights of a power-driven vessel underway. Not under command (Rule 27(a)): two all-round reds in a vertical line, with sidelights and sternlight only when making way through the water. Aground (Rule 30(d)): two all-round reds in a vertical line together with anchor lights.

By day it is a cylinder for constrained by draught, two balls for not under command, three balls for aground.

What fog signal does a vessel constrained by her draught make?

Under Rule 35(c), one prolonged blast followed by two short blasts, at intervals of not more than 2 minutes — the same signal as a vessel not under command, restricted in her ability to manoeuvre, sailing, fishing, or towing or pushing another vessel.

Does Rule 28 apply in US inland waters?

No. Rule 28 is in the International Rules only; the US Inland Rules have no constrained-by-draught signal.

How might Rule 28 come up in an MCA oral?

It may come up as a lights question, then a conduct question. Examples of the kind of question to be ready for:

“At night, fine on your bow, you see three all-round red lights in a vertical line above a masthead light. What is it, and what do you do?”

“Does she have to show those lights?”

“Where does she sit in Rule 18?”

“What would you hear from her in fog?”