Man overboard marker is a device fitted on the outboard side of ship’s bridgewing attached to a lifebuoy. If any crew member or passenger falls overboard personal on board will quickly release the MOB marker which will fall into sea and float emitting orange smoke and flashing lights. The purpose of Man overboard marker is to mark the position of person fallen overboard for rescue operation.

SOLAS require at least one Man overboard marker to be mounted on each bridgewing. Man overboard marker (MOB) need to be attached to a lifebuoy weighing 4kg with a lanyard. When there is a man over board emergency the lifebuoy and Man overboard marker must be released. Release mechanism allows automatic and manual release.

Once released the marker will float in sea attached to the lifebuoy and produce dense orange smoke for at least 15 minutes and two lights will burn for at least 2 hours as a day and night signal.

SOLAS require MOB marker be able to be operable from a mounting height of at least 30M.

Potassium chlorate is the main ingredient in MOB marker.  Chemical reaction of potassium chlorate with other ingridients inside generates the dense Orange smoke.

When MOB marker is transported by sea as a cargo same must be consigned as per IMDG Code regulations as it falls under classification criteria of explosives. Some of the MOB markers are classified as UN 0507 Class 1.4S or UN 0197 Class 1.4G.

However MOB markers fitted on board vessels and in its store as part of life saving appliances do not fall under the purview of IMDG Code as Regulation 2 of SOLAS Chapter VII Part A (Carriage of Dangerous Goods in Packaged Form) states the provisions of this part do not apply to ships’ stores and equipment.

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• Man Overboard – Are AIS SARTS the Best MOB Devices?
• Dangerous Goods on Passenger Ships