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The Basics of the Sea Rules of the Road in Navigation

written by: Manu • edited by: KennethSleight • updated: 5/5/2009

There are no roads at sea, so how does one ship (or vessels, which means all watercraft regardless of size) behave when it comes across another? Their behaviour is governed by the Rules of the Road, or Navigation Rules -ROR. These also cover lights and shapes a vessel must show by night/day

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    Even if you have never been on a ship, I'm sure you know the meaning of the rules of the road. After all this is a very elementary term and does not require any specialised knowledge to know the same. Needless to say rules of the road refer to those laws and regulations which are necessary to maintain traffic discipline and ensure safety of life and vehicles on the road.

    Talking in context of ships which sail in vast oceans and seas where there are no concrete roads, you might be a bit surprised to know that the rules of the road have to be followed by the marine vessels as well. In this case these rules is known as sea rules of the road or navigation rules of the road. Just see what happens when these rules are not followed in the adjacent images.

    Why ROR is Necessary  

    The purpose of these sea rules of the road is the same as that on land, namely to maintain discipline of marine traffic and ensure safety of life. We are all aware of the basic rules of the road on land such as keeping your vehicle on a particular side of the road, ways to overtake other vehicles and so forth; but do you know what is the equivalent of these rules see? If not, just find out below.

    ROR Requirements  

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    Sea Rules of the Road

    The navigation rules of the road are defined by the International Maritime Organisation in what is known as COLREGS or the International Regulations For Preventing Collisions At Sea 1972. In total there are thirty eight rules which are given in five parts A, B, C, D, and E which refer to the rules relating to General, Steering and Sailing, Light & Shapes, Sound and Light Signals and Exemptions respectively.

    Apart from these five categories, there are four Annexes from Annex I to Annex IV which define the technical requirements. If you think that these rules are only applicable to large ships or yatchts and have nothing to do with small boats or naval vessels, then you are certainly wrong. These rules are applicable from the tiniest boat to the largest ships sailing across the oceans.

    A thorough knowledge of the Rules of the Road is essential for practical navigation as well as for passing the various exams and certifications relating to navigation since they are applicable to all types of ships. Rules are rules, and hence even for marine vessels remaining in inland waters, these rules are made by local authorities but they must be in confirmation by the outline laid out by the IMO ROR and cannot differ totally from them. Similarly there could be a slight variation of these rules while applying them to specific ship types and shapes such as for example say naval aircraft carrier ships, dredgers, minesweepers and so forth.

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    Rule of Good Seamanship

    It has been often said that rules need to be followed more in the spirit rather than in the letter. The same is true about the sea rules of the road and there is a rule known as Rule 2, which is an overriding rule, often called the "Rule of Good Seamanship". It says that in addition to all the Rules, the customary practices of good seamanship must be followed, specially when there are special circumstances, when it allows a a departure from the strict language of the Rules to avoid immediate danger – the avoidance of collision being of prime importance. Strict literal compliance with the Rules may not be a defence if a collision occurs.

    The rules primarily lay down the responsibilities between vessels when they meet at sea, ie which vessel should keep out of the way of the other (the give way vessel) and which should do nothing except maintain its course and speed (the stand on vessel). This responsibility also extends to type of vessels in the encounter when a risk of collision may exist- eg, a normal power driven merchant ship should keep out of the way of a vessel restricted in her ability to manoeuvre for any reason.

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    Some definitions regarding ROR

    having learnt about the basics of the rules of the road at sea, we will now proceed to learn a few basic definitions regarding ROR

    - A power driven vessel is a vessel under mechanical propulsion of any kind.

    - the term sailing vessel applies only and only to a marine vessel if it is not using mechanical propulsion at all. If the vessel is using a combination of mechanical power and sails it is classified as a power driven vessel and does not come within the definition of a sailing vessel.

    -The term "vessel engaged in fishing" means any vessel fishing with appartus that restrict her maneuverability- so, a pleasure boat with a couple of lines out is not a fishing vessel under ROR.

    -“Seaplane" includes any aircraft designed to maneuver on the water.

    - a vessel is said to be not under command when her exceptional circumstances prevent the navigating officers on board the vessel to manoeuvre her in a manner required by the rules of the road; therefore such a vessel is not in a position to keep out of the way of other vessels.

    - sometimes a vessel may be severely restricted in her manoeuvrability because of specialised or complicated task she is performing which could be cable laying, survey, minesweeping and so forth and such a vessels is known as the "vessel restricted in her ability to maneuver".

    - A "vessel constrained by her draft" means a power driven vessel which because of her depth 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.

    -The word "underway" means a vessel is not at anchor, or made fast to the shore, or aground. So for example, a vessel with her engines stopped and drifting is underway, and must comply with the rules.

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    Subsequent articles

    In the next couple of articles, I will outline what the rules say specifically about the action vessels must take to avoid collision- whether in good or bad visibility or whether by day or night.

Marine Navigation: The Rules of the Road

  2. Basics of the Sea: Rules of the Road - In any Condition of Visibility.

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