The rules of the road for seagoing vessels is essentially a nautical version of the high way code. These are collectively known as the IRPCS (International Regulations for Prevention of Collisions at Sea) or COLREGS.
Generally, a powered vessel will give way to a non-powered craft unless it is restricted in its ability to move .
A vessel could be restricted in it's manoeuvrability if it is damaged, has dropped anchor or is a large vessel which must keep to the deep sections of a navigable channel.
If two vessels are of the same type then the craft which has the other on it's STARBOARD side must GIVE WAY (in exception of the conditions outlined above). In doing so, the vessel which is giving way should alter course such that it passes behind the other vessels STERN.
If two vessels are heading head-to-head then they both alter their course to STARBOARD such that they pass PORT to PORT .
In any case, the overtaking vessel must always keep well clear of the vessel being overtaken and be willing to give way if necessary.
Think, PORT OK
Collision avoidance overview:
- Powered vessels give way to non-powered vessels
- Powered vessels give way to fishing boats, dredgers, and tugs with a tow over 200m.
- Canoes give way to sailing boats
- Pulling boats give way to sailing boats
- Canoes give way to pulling boats
- Two vessels of the same class "give way to the right"
- Vessels heading head-to-head pass port-to-port
- The overtaking vessel keeps clear
Know the rules well enough to avoid getting into a situation where the ship has to take avoiding action.
Collision avoidance at night
Collision avoidance at night employs the same rules as before but it requires one to know about navigation lights and the different colours which are shown.
There are 4 main colours of light which crop up in all areas of night navigation:
RED is visible off the PORT beam
GREEN is visible of the STARBOARD beam
is shown on the MASTHEAD or STERN or other position
YELLOW is visible from any other position
One way of remembering which colour is used for port and starboard is
"There is no PORT LEFT in the cupboard".
A good way of knowing when to give way at night is to think of traffic lights- When approaching off a vessels PORT beam you should give way (as explained earlier) and you will see a RED light.
RED means STOP (give way)
From the way in which a craft displays its navigation and *steaming lights it is possible to determine the type and size of vessel as well as it's status.
*Steaming lights are those lights shown from the mastheads when the vessel is underway.
Sound signals are used by vessels to indicate their intentions to another vessel by use of their horn.
The internationally recognised set of sound signals are:
1 short blast = Turning to STARBOARD
2 short blasts = Turning to PORT
3 short blasts = Engines going astern
4 short blasts = Pilot boat
5 short blasts = Danger Signal (Possible confusion or imminent collision
(Also adhered to on canals and other inland waters)
1 long blast = leaving port
2 long blasts followed
by the relevant number = I intend to pass you on your
of short blast(s) (port/starboard side).
In international waters, the sound signals are used to signal actual rudder movements.
On inland waters the signals are used to indicate your intentions. In this case the other craft must send an agreement signal before you can change course.
In addition to the above sound signals, there are a set of sound signals a vessel must use when making way in fog. These are known as fog signals.
Fog signals are made up of 3 different types of sound:
- A fog horn
- A bell
- A gong
Boats under 12m are only required to carry some form of fog horn (e.g. canister operated).
Boats over 12m must also carry a bell
Vessels over 100m are required to carry a gong as well
The most common fog signals are:
|under sail||one long blast and two short ones every 2 minutes|
|under power||one long blast every 2 minutes|
|under way||two long blasts every 2 minutes|
|aground (under 100m)||three bells followed by rapid ringing followed by 3 bells|
|at anchor (under 100m)||rapid ringing of bell at 1 minute intervals|
|pilot boat||one long blast followed by 4 short blasts every 2 minutes|
NB: short blast = 1 second
Long blast = 4-6 seconds