Day shapes: motor-sailing cone, not under command, diving

Navigation Rules, lights & bridges · Power & sail

Day shapes are the daytime version of special lights. A recreational boat may need an anchor ball, a cone point-down when motor-sailing, two balls when disabled, or a rigid flag 'A' when diving. Inland Rules excuse some boats under 12 meters (39.4 ft) (Inland Rules 20, 25, 27, 30).

When shapes are used

• The rules on shapes apply by day, in all weathers (Inland Rule 20(a), (d)).
• Shapes are black. A ball, and the base of a cone, are at least 0.6 meter [about 2 ft] across, and a cone is as tall as its base is wide. Vessels under 20 meters may use smaller shapes in proportion to their size (33 CFR 84.06).

Motor-sailing cone

• A vessel under sail that is also being driven by her engine shows a cone, point down, forward where it can best be seen (Inland Rule 25(e); COLREGS Rule 25(e)).
• Inland Rules: a vessel under 12 meters (39.4 ft) need not show the cone but may. The International Rules have no exemption, so every sailboat motor-sailing seaward of the demarcation lines must show it.

Not under command

• A vessel that through some exceptional circumstance can't manoeuvre as the rules require, such as one that has lost her steering, is 'not under command'. She shows two balls in a vertical line by day and two all-round red lights at night (Inland Rules 3(f), 27(a)).
• If she is still moving through the water at night, she also shows sidelights and a sternlight (Inland Rule 27(a)(iii)).
• Vessels under 12 meters (39.4 ft) need not show these signals (Inland Rule 27(g)). They are not distress signals (Inland Rule 27(h)).

Diving operations

• When a vessel engaged in diving operations is too small to show the full restricted-in-ability-to-manoeuvre display, she shows three all-round lights in a vertical line (red, white, red) and a rigid replica of International Code flag 'A' at least 1 meter [3.3 ft] high, visible all round (Inland Rule 27(e)).
• The under-12-meter exemption does not cover diving; small dive boats still need these signals (Inland Rule 27(g)).
• Some states add their own divers-down flag rules on top of the federal signal. Florida, for example, sets its own divers-down warning device requirements (FWC).

The rules: Inland Rule 3 · Inland Rule 20 · Inland Rule 25 · Inland Rule 27 · COLREGS Rule 25 · COLREGS Rule 27 · 33 CFR 84.06

A plain-language summary of federal rules for recreational boats, checked against the rules’ own text and a second source, and written in our own words. It isn’t legal advice. States add rules of their own, and rules change — the links above go to the current official text.