The towing mentioned in this section, refers to the towing of one vessel by another in an emergency and not the professional towing of a vessel by a tug/salvage vessel.

All vessels usually have a dedicated towrope/wire which is specially made up for use during an emergency. Depending on the size of the vessel, this could consist of FSWR (flexible steel wire rope) or nylon. Other man made ropes, such as polypropylene, which are used for berthing hawsers are not suitable for towing because of their lack of elasticity. In the case of FSWR, which on its own also lacks elasticity, the tow rope/wire is shackled to the anchor cable and the latter then veered to a predetermined length. The weight of the cable then acts as a shock absorber and provides the elasticity which the FSWR lacks. In a towing situation it is preferable that the towed vessel provides the tow since it is easier for it to recover the towrope/cable using the windlass on her fo’csle. Even the nylon tow rope is shackled to the anchor cable and the anchor cable is then veered to just beyond the bull ring/bower hawse pipe. This is done to prevent the nylon from chaffing on the ship’s structure.

Basic procedure for towing.
The towing vessel will approach the vessel to be towed as close as possible. The vessel supplying the tow rope will fire a thin nylon gun-line either by special line- throwing gun or rocket over the other vessel.

Attached to the gun-line will be a coir messenger which is a bit thicker than the gun-line and attached to this will be a heavier messenger of either manila or nylon. Finally the towing hawser will be attached to the manila messenger. These lines are then hauled over to the towing vessel first by hand for the lighter messengers and then by winch for the heavy messenger and towing hawser. Before this happens, special preparations are made onboard both vessels to secure the towing hawser. On the vessel to be towed the crew will do the following:

1. The messengers and towing hawser are flaked out on the foc’sle and attached to one another.
2. One of the anchors is disconnected from its cable and secured in the hawse pipe.
3. The towing hawser is shackled to the end of the anchor cable.
4. The coir messenger is fed through the bull ring and attached to the end of the gun line.

On the towing vessel the following will be carried out:

1. A special towing pendant of FSWR is shackled to a special towing deck clench and led around the towing bollards on the poop or quarter deck.
2. A special towing slip is attached to the end of the towing pendant. The towing hawser is shackled to this slip via a towing shackle. The slip is designed in such a way that the towing hawser can be easily slipped in case of an emergency.
3. The towing pendant is led through one of the fairleads in the stern and secured onboard.
4. The pendant is usually covered with a piece of canvas and heavily greased where it passes through the fairlead and the fairlead itself is packed with wood to prevent chaffing of the tow.

Once the messengers and towing hawser are brought onboard the towing vessel, the towing shackle is shackled to the towing pendant. On the towed vessel, the towing hawser is paid out until the towing vessel has connected the tow. Once connected, the towed vessel will veer the anchor cable under control until the bight of the tow is below the surface of the sea. The towing vessel will then get under way and the amount of anchor cable veered sufficiently to keep the towline beneath the surface of the sea.

Precautions when towing.
There are a few precautions to be observed during towing operations:

1. The towing speed should not exceed 10 knots.
2. To reduce the amount of stress on the tow, the towed vessel should either allow the propellers to rotate freely if geared, or to disconnect the propeller shaft from the engine to allow the propeller to rotate freely.
3. The nip of the cable through the towing fairlead should be refreshed on a regular basis to prevent chaffing.
4. The tow must be manned on a continuous basis so that the necessary action can be taken should any problem arise.
5. There should be radio contact between the persons mentioned in sub-paragraph 4.
6. The towline must not be allowed to lift clear of the surface of the sea.