01 NOV 2010
By Yves Beeckman,
Marine Superintendent, URS, Antwerp.
Yves Beeckman highlights the importance of master-pilot exchange addressing the specific issue of tug operations.
It is generally assumed that tug operations are routine for ships' crews and that mooring parties will handle them efficiently and swiftly. As a result, master-pilot exchanges do not usually address this issue. However, in order to ensure effective harbour towage operations, it is essential that the relevant information is exchanged between the master and the pilot beforehand, so that the mooring parties can be called to their stations in time, fully briefed on the details of the operation. Daily experience in a harbour towage department shows that, unfortunately, the number of less-skilled mooring parties is on the increase. This lack of skill may result in delays in securing a tug, putting time pressure on the crew and thereby increasing the risk of personal injury or of the vessel sailing in unsafe conditions, for instance in dense traffic, before the tug is ready.
Exchange information beforehand
The tug information can be exchanged during the voyage under the pilot's advice, as opposed to being exchanged at the time of pilot boarding, when there are other navigational priorities to be addressed. At the start of the towing operation the parties should all be at their mooring stations in good time and have the heaving lines ready at the correct/required position. The master should discuss the ETA at the rendezvous point and ensure that he musters the crew on time, allowing for the distances to the mooring stations to be covered in time, without the need to run. If the operation is to take place at night, the crew should have ample time to wake up and prepare for the period out there, possibly in adverse weather conditions.
Information required to be passed from pilot to master
Due to the different types and sizes of tugs, there are many different types of harbour towage manoeuvres, so the master should find out the following details from the pilot in order to pass them on to his crew:
- ship's lines or tug line
- type of tow wire (steel, synthetic, size, indication of their size)
- method of getting the tow wire on board or the ship's lines to the tug. (most commonly for tug's lines: thin heaving line from the vessel to pick up a larger size messenger rope from the tug, which can be led to the warping drum of a winch in order to heave on board the tow wire. When using ships' ropes, the other option is to lower a ship's rope or send it over with a heaving line. Most tugs will, however, not take a lowered line when underway), only when departing from the berth
- position for passing over the heaving line (throw from the ship's shoulder, which fairlead the heaving line should be taken through)
- maximum speed for securing the tug, so the bridge team can monitor
- bollard pull of the tug(s)
- VHF channels to be used for working with the tugs
Information required to be passed from master to pilot
The master should provide the following information to the pilot:
- SWL of the mooring / towing equipment
- Which fairleads are suitable for securing the tugs. If they are off centre and only one tug is to be used, this must be specifically brought to the attention of the pilot.
- Pushing point strength, if known. If no pushing points are indicated on the hull, but the ship has a reinforced belt all around, it is important to convey this fact to the tug master.
What the crew should know
The officer in charge must ensure that the mooring party knows which bollard(s) will be used for the tug(s), how the messenger line will be led towards the warping drum and how the tow wire will be stopped off in order to allow the strain to be taken off the messenger line and the soft eye to be put over the bollard. They should also be aware of the releasing procedure.
In order to avoid disruption, if there has been a crew change, the new crew should familiarise themselves with the mooring equipment before taking their stations for the first time.
Regular meetings should be held to remind the crew of the risks of handling tow wires and to discuss the procedures.
During the operation
The commands used by the officer in charge should be clear and well understood by the deckhands; standard terminology may be developed, subject to the ship's working language.
The crew should wear leather working gloves or gloves made from equivalent materials when handling a tow wire, never cotton gloves. Very loose work clothing should also be avoided. Overalls should be tight, especially around the wrists and ankles.
Many serious personal injury incidents in mooring areas involve parting lines. It is therefore important to note that a "snapback zone" exists when a mooring line is under tension. Crews should take that into account during operations and it may be a good idea to indicate these areas permanently on the deck. As soon as the tug is secured, all crew stand back from the snapback zones. Crew members should also be warned to beware of hands and fingers: sudden jerks in the tow wire while taking the line on board or releasing the tug can easily lead to personal injury.
The officer in charge must always be in visual contact with the tug during securing up, so he can exchange hand signals with the tug crew, which is usually better than trying to handle a walkie-talkie VHF in windy conditions. There are ships in which the bulwarks are so high that the tug crew can not see anybody on the (forecastle) deck of the vessel, or anything that goes on there. In such conditions, it is absolutely essential to have one person in a specific location for signalling visually to the tug. The crew should always signal to the tug when the tow wire is secured and the tug can safely start applying power. Status of the tow wire should also be confirmed to the master (secured, in the water, propeller cleared).
Only a suitably weighted heaving line should be used. Monkey's fists should not have additional weight, but a heaving line should not be thrown without a monkey's fist. The latter may be blown away and may be impossible to get across to the tug. The crew should have a second heaving line ready to throw in case the first one should end up in the water. The ship's crew should always warn the tug crew before sending the heaving line across. The crew should never use a thick messenger line to throw to the tug, instead of a normal heaving line: the weight of the line coming down may injure the tug crew; it is also more difficult to tie two messenger lines together (a rope messenger line will typically be a three strand polypropylene rope of 24mm diameter).
A tow wire should never be grabbed from below, but always from above.1 If the wire has to be released quickly in an emergency, it is always easier to just release your grip on the wire and let gravity do the work than to pull your fingers away from underneath the wire.
The messenger line must never be disconnected from the tow wire. As an alternative, after securing the wire over the bitt, the shackle can be disconnected from the soft eye of the tow wire and reconnected immediately, over the wire behind the soft eye, as a "running" shackle. This provides a means to give sufficient power to the tow wire to create enough slack so that the soft eye can be lifted easily from the bollard. If this is not done, the shackle connecting the messenger line to the tow wire should not be allowed to become jammed between the bollard and the tow wire. This would cause a sharp bend in the tow wire under load, which might cause it to snap. The tow wire should never be stopped by simply putting it on deck and standing on it; the wire is too heavy and you may be thrown off your feet or dragged along. Very serious injuries will result in most cases. The crew should also beware of "snaking" messenger lines when they are released and run out. They could seriously hurt someone upon impact.
Normally, the bow tug will have no problems when the tow wire is released in one go; the tug will be moving away from the vessel and there will be little risk of the tow wire ending up in the tug's propellers. However, the crew should always try to obtain confirmation from the tug of how they want this done. The stern tow wire must always be released in a controlled way (slacked away by means of the messenger line, in co-ordination with the tug crew). When you let it go in one motion, it will most probably end up in the tug's propellers.
Tug emergency "let go" procedures
Tugs working on a towing winch have a "let go" system. The ship's crew does not have to do anything to disconnect the wire; that will be done by the tug master. He will set his winch drum free and let the wire run out, until it breaks from its securing bolt on the winch drum, while he manoeuvres his tug to safety.
However, this leaves the ship's crew with a problem: the vessel will be trailing up to 140m of steel wire, which has to be recovered from the water before the tug can make a new approach (to secure up with its spare towing wire). When making speed through the water, this will be a difficult job for the mooring party, because once the messenger line is entirely on board or on the warping drum, it will be much more difficult, probably even impossible, to wind the remaining towing wire in on the warping drum. In this case, a stopper must be used, and a (second) messenger line tied to the towing wire further down the line, and then winding the wire on board can be resumed. This process may have to be repeated a considerable number of times. It will probably be necessary, if conditions allow, for the vessel to reduce speed. This is a dangerous operation and great care must be taken when carrying it out.
1 Towing wires typically have the following dimensions: for 45 ton bollard pull: 42mm diameter; for 65 ton bollard pull: 48mm diameter; for 80 ton bollard pull: 54mm diameter.