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Emergency signals and response for ships

Lifebelts and line throwing devices

Lifebelts and line throwing devices

As a first form of assistance for someone in the water, the lifebuoy is probably the easiest to carry and use. The exact number of lifebuoys that must be carried depends upon the length of the vessel and whether it is a cargo or passenger ship. The minimum number of lifebuoys on the smallest vessels (under 100m for cargo ships and under 60m for passenger vessels) is eight.

SOLAS requires the lifebuoys to be distributed so as to be readily available on both sides of the ship and as far as practicable on all open decks extending to the ship’s side. At least one should be placed in the vicinity of the stern. They must also be easy to cast loose and not be secured in any way. At least one lifebuoy on each side of the ship must be fitted with a buoyant lifeline equal in length to not less than twice the height at which it is stowed above the waterline in the lightest seagoing condition, or 30m, whichever is the greater.

At least half of the lifebuoys must be fitted with self-igniting lights and at least two of those should also be equipped with automatic smoke signals and be capable of quick release from the navigation bridge.

The requirement for light and smoke is to keep a visual fix on the lifebuoy while the ship performs the necessary man overboard manoeuvre. This has been partially replaced by the MOB button on the GPS but, whereas that will indicate the exact position the alarm was raised, the visual aids on the lifebuoy will help rescuers allow for current and drift.

Lifebuoys should be checked regularly for flotation performance as it is not unknown for the filling material to deteriorate to such an extent that the lifebuoy becomes unserviceable while appearing to be in perfect condition.

Line throwing devices

As well as the use of lifebuoys, passing a line to a person in the water or across to another vessel is often essential in emergencies so it is not surprising that there is a mandatory requirement to carry a line-throwing appliance. SOLAS says that the line thrower should:

  • be capable of throwing a line with reasonable accuracy;
  • include not less than four projectiles each capable of carrying the line at least 230m in calm weather;
  • include not less than four lines each having a breaking strength of not less than 2kN;
  • have brief instructions or diagrams clearly illustrating the use of the linethrowing appliance.

The rocket, in the case of a pistol-fired rocket, or the assembly, in the case of an integral rocket and line, shall be contained in a water-resistant casing. In addition, in the case of a pistol-fired rocket, the line and rockets together with the means of ignition shall be stowed in a container which provides protection from the weather.



 Flares & smoke signals

For cases where use of GMDSS equipment is impossible and for attracting attention of search and rescue aircraft and ships, the use of pyrotechnics is called for and required under SOLAS. The universally-known red distress flare is the most useful for attracting attention over a distance, with hand flares and smoke being used for shorter distances.

A rocket parachute flare can be seen from a distance of up to 30 nautical miles under optimum conditions at night and from eight nautical miles during daylight. SOLAS requires ships to maintain a stock at least 12 flares on the bridge and no less than four in each lifeboat or liferaft.

Hand-held flares and smoke signals have a much shorter range and are intended to allow search and rescue craft to pinpoint the position of any survival craft. Each lifeboat or liferaft should be equipped with six hand flares, two buoyant smoke signals and an electric torch with spare batteries and bulbs suitable for Morse signalling. Also in the survival craft should be a signalling mirror, whistle and a copy of the life-saving signals on a waterproof card.

Pyrotechnics have an expiry date and should be replaced before they expire. Failure to have sufficient pyrotechnics on board and in survival craft will cause a ship to be detained by PSC inspectors. Pyrotechnics should only be used when there is reasonably good chance that they will be seen. Parachute flares burn for a minimum of 40 seconds falling from a height of about 300m. Instructions for use should be printed on the flare, presented in a picture format.

Hand flares are used to guide the searching ship or aircraft or pinpoint the survivors’ position. They burn for a minimum of one minute and are ideal for day or night use and have a range of five nautical miles by day and 10 nautical miles at night.

The effectiveness of smoke signals as a means to raise an alarm is doubtful, but they can be used to pinpoint the survivors’ position. They will be more readily seen from an aircraft than a surface craft. They are for daytime use only and smoke for a minimum of three minutes.

Their range is at the most about two to three nautical miles in good visibility.

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