Berthing a Single-Screw Coaster in an Onshore Wind
M/V Kystvakt, 132 m LOA, 18.5 m beam, draft 5.6 m fwd and 5.8 m aft, single right-hand fixed-pitch propeller, 600 kW bow thruster, no stern thruster. You are the master and are about to berth starboard side to at an open quay in a Norwegian port. The berth runs north–south on the east side of the basin, and the ship must end up heading about 000° alongside. Wind is NW 20 kt, gusting 28 kt; the tidal current sets southward along the quay at 0.8 kt. One 2,500 hp tug is available and will make fast forward. The basin is 350 m wide, with a shallow patch of 6.0 m to the south of the berth. It is 30 minutes before high water slack.
1. Describe your approach plan: from which direction, on what heading and speed, and how the wind and current are used.
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Geometry and forces. The berth is on the east side and the ship must finish heading 000° with her starboard side to, so the approach comes from the south, heading north. The NW wind (315°) is on the port bow, setting the ship to starboard - onto the quay: an onshore wind. The 0.8 kt current sets south, meeting the ship head-on, so it reduces speed over ground and helps control, but it will also set the ship southward once stopped.
Plan.
- Approach from the south along the quay line at about 3 kt over the ground, heading 005–010°, closing the berth at a shallow 10–15° angle.
- Keep 1.5–2 ship's widths off until the stern is nearly abreast of the after end of the berth, then let the wind and a little port helm bring her alongside.
- Bow thruster and tug ready before the final approach; the tug forward is there to hold the bow off, because the wind wants to push it on.
- Have the forward spring and head and stern lines ready. The shallow patch (6.0 m against 5.8 m draft) south of the berth is a no-go area, so do not overrun to the south.
Brief the crew and the tug before starting and agree the abort signal.
2. How do you use the engine, rudder, bow thruster, tug and lines to bring the ship alongside without damaging her?
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Using the controls.
- Engine and rudder: keep steerage way at about 3–4 kt through the water; the head current means speed over ground is lower. Use short kicks ahead rather than continuous power.
- Transverse thrust: with a right-hand propeller, going astern walks the stern to port and the bow to starboard - toward the quay here. Avoid heavy astern power near the berth, or use it deliberately only when you want the bow to come in.
- Bow thruster: use it against the wind, pushing the bow to port to hold the ship off while the stern closes. It loses effectiveness as speed rises, so it works best slow.
- Tug forward: made fast before the final approach, it holds the bow off and can pull it to port if a gust sets the ship on.
- Lines: land the forward spring first, then the stern line and head line. Use the spring with slow ahead and helm to spring the bow in or hold the ship alongside, and watch the lines as the ship moves with the tide.
- Keep talking to the tug and the line handlers; the gusts are what will catch you out.
3. State your abort criteria and the escape plan.
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Abort criteria (agreed before the approach):
- Sustained wind above about 25–30 kt, or a gust the bow thruster and tug cannot hold against.
- Tug not fast and in position 0.5 NM from the berth.
- Bow thruster, engine or steering failure, or loss of the tug line.
- The ship cannot be held within the planned approach corridor, or speed over ground exceeds about 4 kt at the berth.
- Any doubt about the depth over the shallow patch or the berth soundings.
Escape plan. The basin is 350 m wide: go astern, back out north into deep water, and either hold off with the tug or anchor clear of the berth. Do not try to force the ship alongside with power against an onshore wind - that is how hulls are holed and lines part. Wave off and wait for the wind to moderate or the tide to ease; the berth will still be there.