Berthing a Loaded Tanker in Cross-Current
M/V Solvang, a 45,000 DWT product tanker, 180 m LOA, is arriving at the Karmsundet terminal at 1400. The ebb current sets across the berth from starboard to port at 1.8 kn; wind is NW 18 kn. One 40-tonne bollard-pull tug is available at the starboard bow; no stern tug. The ship is in ballast, draft 6.5 m, UKC 1.2 m in the channel. The plan is to berth port side to, with the berth on the port side. The channel is 120 m wide, and a bank effect is expected from the starboard side. A passing ferry may create a surge. Approach speed is 4 kn over ground. The berth is parallel to the channel.
1. Assess the effects of current, wind, bank, and tug allocation on the planned berthing.
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The 1.8 kn current from starboard to port sets the ship onto the berth and increases the effective approach speed and drift angle. The NW 18 kn wind may oppose or complicate the approach. One bow tug can check the bow and pull it to starboard, but without a stern tug the stern will be set down onto the berth; the ship may pivot around the bow. Bank effect from the starboard bank can repel the bow and attract the stern, causing sheering and loss of control. A passing ferry's surge can destroy the approach. UKC 1.2 m means squat and bank effect must be controlled, so speed over ground must stay low.
2. Describe the approach and berthing manoeuvre.
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Plan a ferry-angle approach: head the ship slightly into the current, starboard of the berth heading, so the current carries her sideways onto the berth while the bow tug checks the bow. Approach at a shallow angle of about 15–20° at 2–3 kn over ground. Use the bow tug to control the bow and engine and rudder to hold the stern. Have both anchors ready; consider using the starboard anchor to check the swing if the bow tug cannot hold. Moor spring first to stop the ship, then head and stern lines. Keep the tug on the starboard bow until all lines are fast. Use VHF with the pilot, tug, linesmen, and VTS.
3. What are your abort criteria and communication requirements?
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Abort if the current exceeds 2 kn or sets more strongly onto the berth, if the tug fails, if approach speed exceeds 4 kn, if the ship cannot hold the ferry angle, if a passing vessel creates an uncontrolled surge, or if UKC falls below plan. Go around or anchor. Communicate the abort clearly to VTS, the tug, and the linesmen. Do not attempt to save a bad approach. Record the decision and the reasons in the bridge log.