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IRPCS ColRegs - Maritime Navigation Rules of the Road

Sections: ColRegs Rules of the Road Lookouts Avoidance Racing Rules Evasive Action Traffic Separation Factors Signals

International regulations known as Colregs and navigation lights and shapes. Sailing rules of the road international rules of the road at sea or IRPCS rules and sailboat racing rules tutorial.

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A powerboat is about to cross paths with a sailboat under sail. What should the powerboat do?

In the navigation rules what is the duty of the stand on boat?

ColRegs - International Regulations for Preventing Collisions at Sea

Copies of the IRPCS regulations or Colregs can be bought but are reprinted in almanacs. National governments and local authorities impose their own regulations covering harbours, rivers, or inland waterways in addition to the Col Regs with details being found in local pilot books. Have a ready reference to the colregs available in the cockpit so that any unfamiliar situation can be checked.

Along with these maritime navigation rules, the skipper of a sailing vessel fitted with a motor should be aware of the diverse rules that apply when sailing and when motoring. Racing skippers should abide by additional rules which are based on the IRPCS.

IRPCS Marine Navigation Rules of the Road

Sailors refer to the 'marine navigation rules of the road', which are the marine navigation rules they are most familiar with and apply to their everyday use in confined channels where the application of the rules prevents a collision with other vessels.

The purpose of these rules of the road when sailing, is to prevent confusion when vessels are approaching, given that ships and boats are free to move in any chosen direction. Large ships follow well-charted sea routes, but smaller sailing vessels have greater freedom in movement and do cross these routes.

The colregs rules of the road are specific as to the duties that each vessel must observe. In situations in which two vessels are approaching each other, the rules designate one as the give-way vessel, whose duty is to take avoiding action and the other, the stand-on vessel, whose duty is to take right of way.

The give-way vessel must take positive action in plenty of time to avoid a collision, and course alteration or change in speed should be obvious to the other vessel. The master of each vessel has an expectation that the other will act according to the maritime navigation rules, but should be prepared to take avoiding action if necessary.

Confusion can arise trying to judge which boat is the stand-on or give-way vessel in a situation. When [ under power] it is easily understood by referencing the sectors of the [ basic navigation lights ]. Under sail and sailing to windward on port tack, it may be difficult to decide, especially at night, if a boat to windward and running downwind is on port or starboard tack.

If on port tack your boat has right of way and should stand on, but if the other boat is on [ starboard tack ], it has right of way requiring your boat to keep clear. When a powerboat is about to cross paths with a sailboat under sail, the powerboat is to give way in all circumstances. Where there is any doubt, assume that your boat has to give way and be ready to take evasive action early before a danger of collision arises.

Keeping a Lookout

Responsibilities include keeping a constant lookout at all times, proceeding at a safe speed, and when close to navigational hazards taking account of the sea state and wind. Lookouts should use a clock-notation system to tell the skipper where an approaching vessel is in relation to the yacht and an estimate of the distance of the ship and its direction of travel.

A sailing boat underway should keep clear of:

  • A vessel not under command
  • A vessel restricted in its ability to manoeuvre
  • A fishing vessel
  • A vessel constrained by its draught

Fishing vessels are unpredictable as they move in all directions. The ColRegs acknowledge this and the advice is to keep clear of vessels identified by the [ appropriate lights ] or shapes, as fishing vessels.

Commercial shipping should be treated with great caution. Theoretically, they are required to give way to sailing vessels. Usually they are on autopilot in open waters and restricted in narrow channels, so demonstrate your intentions and do not insist on right of way.

Collision Avoidance Basic Rules

As two powered vessels meet and are approaching each other head-on, each should alter course to starboard, so that they pass each other port-to-port. The vessel, which has the other vessel on her starboard side when crossing each other’s path, should keep out of the way, crossing below the other vessel. Remember the rule by this saying, 'If I am on the right, I am in the right.’ An overtaking vessel, approaching from about 22 degrees either side of dead astern, must keep clear of the overtaken vessel.

Racing Rules

Racing rules are formed from rules relating to sailing vessels. Therefore, with two boats on different tacks, the vessel on a port tack (with the wind blowing over its port side) must keep out of the way of one on a starboard tack (with the wind over its starboard side).

When two boats are on the [same tack,] the windward boat (the one closest to wind) must keep out of the way of the vessel to leeward. Any vessel on a port tack and unsure of what tack another vessel is on, must keep out of its way. The windward side, with regard to racing rules, is determined to be the opposite side to that on which the mainsail is carried. Overtaking rules are the same as for powered vessels and are designed to keep the overtaking vessel away from the vessel being overtaken.

Taking Evasive Action

Yacht crews may be small and inexperienced, but it is essential that a lookout is kept at all times. Instruct the crew to alert the skipper whenever an approaching vessel is seen. When your boat is the give-way vessel, or the situation is uncertain, take evasive action well in advance prior to a potential collision. When in a crossing situation with a large ship, there may be uncertainty as to whether your boat and the other boat are on a collision course.

Assessing a Likely Collision

Make use of a [ hand bearing compass ] to take bearings of the approaching ship at frequent intervals. If the bearing remains the identical, then each are on a collision course and immediate action must be taken.

An alternative to taking compass bearings, use a part of the boat, such as a stanchion, as a reference point. The boat is on a collision course if the other vessel stays in line with it; if it moves forward of the reference point it will pass ahead of your boat, if it falls back your boat will pass ahead of it.

Having decided to take avoiding action, make a significant course change indicating that your intentions are obvious to the other vessel. Avoid crossing the bows of another craft which may be moving much faster than thought. If possible, alter course to pass astern of the other vessel or if in doubt, turn onto a parallel course in the same direction as the other vessel and wait for it to pass.

Navigation Light Sectors

The IRPCS rules on navigation lights state that under power, use another power boat's light sectors to decide when to give way or stand-on. In the white or red sectors, give way; in the green sector, stand-on.

Traffic Separation Zones

[ Traffic separation schemes ] in busy shipping areas are in position to keep local traffic separate from through traffic and are split into two lanes . Between the traffic lanes are separation zones which are restricted to fishing vessels, ships in a state of emergency, and those crossing the lanes. Vessels that are crossing a separation zone must do so at right angles.

Entering a traffic lane should be done at the ends of the lane where possible, or at a shallow angle so as to blend into the traffic flow. Local traffic use the inshore zones and keep out of the lanes. If crossing a traffic-separation scheme, it is important that it is done as quickly as possible. Steer a course at right angles to the lane while not adjusting the course to allow for any sideways tidal effect, as this increases the time that it takes to cross.

Other Factors

In narrow navigable channels, it may be impossible to make large course changes without the prospect of going aground. Commercial vessels are constrained by their draft and when in the channels, yachts should keep to the periphery of the channel.

The common 'rule of the road' is that traffic keeps to starboard (the right) while navigating channels. In a channel with blind bends, another rule is that the appropriate sound signals should be sounded prior to engaging in specific manoeuvres.

IRPCS Sound Signals and Daylight Shapes

In clear visibility, irpcs sound signals indicate that a vessel is carrying out a manoeuvre. Under power and in sight of each other, when one boat is altering course, it indicates its intentions by horn signals. When at night, an all-round white light is flashed for the appropriate number of times.

Vessels must use [ shapes ] during the day to make identification easier. An inverted cone shape on the forestay indicates that a yacht is motor-sailing, and a ball shape in the rigging indicates it is at anchor.

IRPCS Sound Signals

[ Sound signals ] comprise of short blasts of 1 second duration and prolonged blasts of from 4 to 6 seconds. A vessel when approaching a blind bend sounds one prolonged blast and another vessel approaching the bend in the opposite direction, sounds a prolonged blast in reply.

In sight of each other the vessels sound:

  • one short blast of a horn means an alteration to starboard;
  • two short blasts of a horn means an alteration to port;
  • three short blasts tell other craft that the sounding vessel's engines are going astern.
  • five short and rapid blasts; signals that the sounding vessel is confused as to the other’s intentions.

In a narrow channel, when a vessel comes up behind and gives:

  • two prolonged blasts followed by a short one, means ' I intend to overtake on your starboard side."
  • two of each means 'I intend to overtake on your port side.'

The signal is acknowledged by four blasts - one prolonged, one short, one prolonged and one short meaning 'I agree and will keep my course.'

When visibility is restricted, there are of a number sound signals that must be understood. The principal maritime navigation rules governing a motor sailing vessel are:

  • when sailing, one prolonged and two short blasts at not more than two-minute intervals;
  • when motoring, one prolonged blast at not more than two-minute intervals.

If you are at anchor in an area where a risk of collision exists, ring a bell or strike a gong for five seconds once a minute.

International rules for the prevention of collision at sea and colregs marine rules of the road at sea situations.

navigation light uses
sound signals
daylight shapes
separation zones
navigation lights
on the same tack
sail on sail
sail under power
hand held compass