There are times when a ship needs to dock at a particular berth terminal. She will either load/discharge a cargo, take in provisions or do bunkering procedures. When at the port, there is also a risk for a vessel to catch fire or have an explosion and this is likely to happen on tanker vessels.
When the crew and port services are unable to contain the fire or there is a risk of explosion, the vessel will have to be towed away from the port. A fire wire will be needed for such a time as this.
What Is The Purpose Of Fire Wire On Ships?
The purpose of fire wire is to allow tugs in a port or terminal to pull the vessel in distress away without the assistance of the ship’s crew. There are different ways to set up the fire wire onboard a ship and this may vary from port to port. Port authorities would advise vessels thru the ship’s agent or a designated person of their requirement.
The fire wire, sometimes also called mooring wire is made of steel wire rope. There were suggestions to replace it with a synthetic wire, however, tests conducted did not give satisfactory results to withstand fire and explosion. Wire ropes possess high strength that allows them to carry tensile forces and can freely move on sheaves of mooring winches.
Some common wires used onboard are single-layer wire rope, filler wire, Warrington wire, and Filler wire. A safety officer onboard must make sure that purchases of wires are from certified suppliers and must be approved by authorities.
Wire rope is made up of strands of metal wire formed together and can either be cable laid right-handed or left-handed. It is also known as Z-lay or S-lay. They are marked by two numbers.
The first number represents the number of strands in the rope while the second indicates the number of wires in each strand. Some wire ropes have a large diameter which consists of multiple strands known as cable laid. The wire certificate is also kept for record purposes and reference for replacement.
Proper care and handling of the fire wire are necessary so as not to affect its strength and usability. They must be properly uncoiled to avoid kinks and twists in the length of the wire. For left-laid wire rope, coiling in the direction counterclockwise is the recommended procedure.
The wrong direction can cause injury or even death to the crew handling the wire. At times, wire ropes tend to resist coiling and uncoiling. Make sure one does not damage the wire by forcing it in the wrong direction.
It must be free from rust, cut strands, paints and chemicals. A competent person must check and record the conditions of all deck equipment. They must be properly stored if not in use to avoid exposure to saltwater and harsh weather.
Emergency Towing Wire Requirements
As per IMO regulation, all tankers vessels with more than 20,000 tonnes deadweights must be equipped with emergency towing at the forward/bow and aft/stern of the ship. They must be secured in bitts with more than 5 turns in each bitt. A wire stopper is also recommended to be used in handling the wires.
It covers gas carriers, oil, and chemical tankers. The towing strength for these gears is about 1000 Kilonewtons for vessels up to 50000 tonnes deadweight. For ships above 50, 000 tonnes deadweight, 2000 kN towing strength is required.
The arrangement includes a towing pennant which can either be wire or fiber rope. This is the main towing line which has a recommended length of more than 80 meters.
The smaller vessel can opt to have a shorter emergency pennant. It is then connected to a pick-up and chaffing gear. Chaffing gear protects the line from damage and wear/tear. The gear then passes thru the fairlead, also known as a chock. The bitter end is then connected to a strong point of the vessel.
At the stern or aft of the ship, a floating buoy and float line must be prepared to be retrieved along with the extension line.
A new provision from the regulation requires that the emergency towing be prepared and set up by one crew member in the forward station at around sixty minutes while the aft towing gear is within fifteen minutes under normal conditions and nighttime operations. This is being checked during a periodic survey and must be maintained in good working condition.
All components and fittings must be marked with their SWL (Safe Working Load). Whenever appropriate, a welded mark indicating SWL in tonnes must be done. This would inform and remind crew members or even stevedores of the capacity of the equipment they are using.
What Is The Use Of An Emergency Towing Arrangement?
When the ship experiences main engine breakdowns, loss of steering, or if the propeller touches the sea bottom and sustains heavy damage, she needs to be towed to safe waters or an emergency dry dock for repairs. As the vessel drifts in the open sea, she could face a lot of danger.
Time is of the essence as the ship can have additional damage the longer she stays in open waters. When the main towline and other mooring equipment of the vessel are also not functioning, the emergency towing would be of great essence. An emergency towing arrangement allows a vessel in distress to be rescued or recovered.
Generally speaking, the emergency towing must be connected to the strong point of the vessel as well as easy access by the salvaging or rescue team. It would be ideal for the line to be floating in the water or close to the water.
It should also have a safe distance from the distressed vessel when the tug starts the operation. Tug maneuvers from the stern leading to the bow, carefully connecting the pennant to the tug hook.
A ship that experiences distress onboard, like fire, flooding, main engine breakdown, propeller damage, or loss of propulsion can still be salvaged and rescued as long as the emergency towing is properly installed and can be fully attached to the salvaging team.