See unitsShip mooring and anchoring stations: mooring and tug lines, safe working loads, the windlass and buoy mooring (STCW A-II/5)
Tug lines and mooring to a buoy
1The lesson in plain words
Tug lines are made fast and let go only on order, and kept clear of once loaded. Mooring to a buoy adds a boat crew and slip lines.
Taking the tug's line
Usually the tug passes up its own towline. On the bridge's order, throw a heaving line to the tug from the shoulder, the curved side near the bow, rather than the centre lead, which puts the tug dangerously close ahead of the bow. The tug bends on a messenger, a lighter line, and you heave the towline's eye aboard with it. The heaving line's weight is a rope monkey's fist or a soft pouch of no more than 0.5 kg, never metal.
Making fast
Use only enough turns of the messenger on the drum end to bring the eye aboard. Hold the towline with a stopper while you put the eye over the bitts the officer names, then clear the area quickly so the tug can move to a safe position. Once the tow is connected, nobody stands near it: a towline can come taut without warning. Report 'tug made fast' to the bridge.
Letting go
Never let go until the master or pilot orders it and the tug is ready. Wait until the tug eases the towline and the officer confirms it is slack. Use the messenger to heave in slack, stopper the towline and lift its eye off. Use turns of the tug's messenger around the bitts to control the towline as the tug retrieves it. A running towline can whiplash or foul the tug's propellers. Never handle a towline under load.
Girting
Girting (or girding) is when a tug is pulled sideways by its own towline, for example if the ship gains speed or turns while the tug lies across her. A tug can heel over and capsize in seconds. The tug master and pilot manage the risk. Follow release orders promptly, but never handle a loaded towline. If it is taut, report this immediately and stay clear until the officer confirms slack.
Mooring to a buoy
A mooring boat takes the ship's line, or a slip wire or slip rope, to a mooring buoy. The boat crew wear working lifejackets, with a lifebuoy and line in the boat; keep a lifebuoy and line ready on deck too. A slip line goes through the buoy's ring and back aboard, so the ship can let go from on board. Never put either slip-wire eye over the bitts: you may be unable to release it under load.
2Key data
- Heaving line weight (COSWP)
- Rope monkey's fist, or soft pouch of 0.5 kg at most; no metal
- Throwing to a tug forward
- From the bow's shoulder, on the bridge's order
- Letting go a tug line
- Only on the master's or pilot's order, tug ready
- Slip wire eyes
- Never put an eye over the bitts; it may become trapped under load
3Key points
- 1
Throw, make fast and let go tug lines only on the bridge's order, and clear the area once the tow is connected.
- 2
Stopper the towline while the eye goes on or off the bitts; never handle a loaded towline.
- 3
Girting can capsize a tug in seconds. On release orders, report any load; handle the towline only after confirmed slack.
- 4
At a buoy: lifejackets in the boat, a lifebuoy ready, and slip lines that can be let go from on board.
4Frequent mistakes
Wrong: Let the tug's line go as soon as the tug stops pulling.
Right: Wait for the master's or pilot's order; the tug must be ready to take its line back.
Wrong: Drop the eye over the side and let it run.
Right: Use turns of the tug's messenger around the bitts to control the towline as the tug retrieves it. A running towline can whiplash or foul the tug's propellers.
Wrong: Weight the heaving line with a shackle so it carries further.
Right: Use a rope monkey's fist or a soft pouch of no more than 0.5 kg. Metal weights injure the receiver.
5Practice case & exam keys
Leaving the berth, the forward tug is pulling on your bow. The ship starts to gather speed and the towline leads more and more across the tug. The pilot orders 'let go forward tug', but the towline is still bar-tight.
Show the answer
Report the loaded towline at once: the tug risks girting. Stay clear; the bridge and tug must ease the load. Once the officer confirms slack, stopper the towline, lift its eye off and control its return using the messenger around the bitts. Stay out of the line's path. Report 'towline released'. Report 'forward tug clear' only when the line is clear of the ship and the tug is safely clear.
Exam keys
- Tug line: heaving line, then messenger, then towline eye on the bitts; stopper while working the eye.
- Make fast and let go only on order; lower the line under control, never let it run.
- Girting: a tug pulled sideways by its towline can capsize. Follow release orders promptly; report any load and stay clear until the officer confirms slack before handling.
- Buoy mooring: lifejackets in the boat, lifebuoy ready, slip lines; never put slip-wire eyes over bitts.
Finish this unit
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