Chapter 27: Navigation Regulations and COLREGS
The International Regulations for Preventing Collisions at Sea define who gives way, how, and what lights, shapes and signals are shown. They are law, not guidance.
Steering and sailing rules
Rule 5 requires a proper look-out by sight and hearing and by all available means. Rule 6 requires a safe speed. Rule 7 addresses determination of risk of collision, warning against assumptions from scanty radar information. Rule 8 requires action that is positive, made in ample time, and readily apparent — large course changes are better than a succession of small ones. Rule 13 gives overtaking: the overtaking vessel keeps clear. Rule 14 head-on: both alter to starboard. Rule 15 crossing: the vessel with the other on her starboard side keeps out of the way. Rule 16 requires the give-way vessel to take early and substantial action; Rule 17 lets the stand-on vessel act when the give-way vessel is clearly not taking appropriate action, and requires action when collision cannot be avoided by the give-way vessel's action alone.
- Head-on: both turn to starboard (Rule 14)
- Crossing: vessel with the other on her starboard gives way (Rule 15)
- Overtaking: overtaking vessel keeps clear (Rule 13)
Responsibilities between vessels and restricted visibility
Rule 18 sets the pecking order: a power-driven vessel keeps out of the way of a sailing vessel, a vessel engaged in fishing, a vessel restricted in her ability to manoeuvre, and a vessel not under command. Rule 10 governs traffic separation schemes: proceed in the lane in the general direction of flow, cross on a heading as nearly as practicable at right angles. Rule 19 applies in restricted visibility: there is no stand-on vessel; proceed at safe speed with engines ready, and if a close-quarters situation with a vessel forward of the beam cannot be avoided, reduce to bare steerage or take all way off.
Lights, shapes and signals
A power-driven vessel underway shows masthead light(s), sidelights and a sternlight; sidelights arc 112.5° each side, the sternlight 135°, a masthead light 225°. A vessel not under command shows two all-round reds vertically, or two balls by day; restricted in ability to manoeuvre, red-white-red and ball-diamond-ball; constrained by draught adds three all-round reds and a cylinder; at anchor, one all-round white forward and a ball. Manoeuvring signals: one short blast altering to starboard, two to port, three astern propulsion, five or more short and rapid for doubt. In restricted visibility a power-driven vessel making way sounds one prolonged blast every two minutes; stopped and making no way, two prolonged blasts.
Key takeaways
- • Rules 13, 14, 15 cover overtaking, head-on and crossing — know them verbatim.
- • In restricted visibility (Rule 19) there is no stand-on vessel.
- • Five or more short and rapid blasts means doubt about the other vessel's intentions.
Knowledge check
Immediate feedback with rationales. Answer each question to see the explanation.
Chapter 27 quiz
0 of 4 answered
1.Two power-driven vessels are crossing; vessel B is on A's starboard bow with risk of collision. Which vessel gives way?
2.Two all-round red lights displayed vertically indicate a vessel:
3.In restricted visibility a power-driven vessel underway and making way sounds:
4.Under Rule 19, a vessel detecting another forward of her beam by radar alone in fog should: