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Lights, Shapes and Sound Signals 

Lights and shapes are used to indicate the status of a vessel at sea and the direction in which a vessel underway is moving, to allow the correct action to be taken by all the vessels when in sight of each other.

The International Regulations for Preventing Collisions at Sea (COLREGs) not only prescribe the actions of each vessel in all states of visibility, they also stipulate the lights that should be fitted to a vessel, the shapes that should be available and the sound signals and signalling equipment necessary, to allow a vessel to make its status clear at all times.

Lights and shapes

The rules concerning lights must be complied with from sunset to sunrise and at all other times in restricted visibility. Shapes are used during daylight hours to indicate a vessel's status and to avoid doubt or confusion. The prime example is the requirement for a yacht that is motor sailing to display a motoring cone (a conical shape apex downwards) in the forepart of the vessel.

The rules also stipulate the exact colour of the lights, their intensity, the minimum distance each light must be visible for, and their position on the vessel. The requirements vary and the rules must be read in full, to completely understand one's obligations. A summary of the rules (in tabular form) designed to help a pleasure boat owner understand his or her obligations with regards lights and shapes is provided under downloads.

It is important to remember that there have been significant advances in technology since the rules were written. It is quite feasible and very desirable to make yourself visible for more than just a mile or two, when you consider that a ship today can cover that distance in little more than a couple of minutes, providing it with insufficient time to identify that it is on a collision course with you, identify that it is the give way vessel and take the necessary action. This is why the RYA recommends that small craft sail defensively, by which it is meant that you avoid creating the situation where the ship is the give-way vessel that may be on a collision course and in close quarters with you in 'stand on' position.

Spare bulbs of the correct wattage should always be carried onboard, together with other electrical spares such as fuses and an emergency alternative to your fixed navigation lights in case they should fail.

The use of LED bulbs in navigation lights is frequently discussed, but until an international standard for their manufacture is introduced, there can be no guarantee that with LED bulbs fitted your nav lights will conform with the COLREGs. Changing to an LED bulb could alter the intensity, the colour emitted or both, so this should be done with great caution.

Sound signals

There are three devices used for sound signalling a gong, a bell and a whistle.

  • A vessel of 12m or more in length shall be provided with a whistle
  • A vessel of 20m or more in length shall, in addition, be provided with a bell
  • A vessel of 100m or more in length shall, in addition, be provided with a gong

The whistle, bell or gong shall comply with the specification in COLREGs 1972 Annex III, although the bell or gong may be replaced by other equipment having the same sound characteristics, provided that manual sounding of the required signals shall always be possible.

Vessels of less than 12m in length are still required to have an efficient means of making sound signals, but they do not need to comply with the technical details for sound signal appliances in Annex III of the COLREGs.

As well as being used to show the presence of vessels in reduced visibility and their status, sound signals prescribed within the COLREGs as manoeuvring and warning signals. Sound signals may also be supplemented with light signals as detailed in the rules. 

Signals to attract attention

To attract the attention of another vessel, the rules permit any light or sound signal, that cannot be mistaken for an authorised signal or an aid to navigation, with the exception of high intensity intermittent or revolving lights, such as strobe lights, which are to be avoided.

In particular directing the beam of a search light in the direction of the danger (being cautious not to embarrass any vessel), is suggested in the rules.

Pleasure craft are encouraged to carry a spotlight or powerful torch (not forgetting the spare batteries and bulb) which they could shine towards the bridge of a ship (being mindful of their night vision) to attract their attention, for example if they are a danger to you and you feel that they are not aware of your presence.

Hand-held white flares are also designed for the purpose of collision avoidance. A white flare is not a distress flare. It is used to draw attention to a vessel's presence, particularly in a potential collision situation where the other vessel does not appear to have seen you. 

Owners of vessels of 13.7m should be aware that white flares are mandatory equipment for Class XII Vessels - refer to Pleasure Craft Regulations for clarification.

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