The Bermuda registered LPG tanker Havkong, berthed at the Braefoot Bay Marine Terminal in the River Forth in fine weather on 23 January 1993. The ship moored alongside, in compliance with the terminal’s Jetty Regulations, including those related to moorings. However the winch and fairlead positions aboard Havkong were such that, despite deploying lines in excess of those required, the final mooring pattern geometry resulted in only two lines contributing restraint against westerly winds.

At 18:50 hours, when Havkong had loaded approximately 6000 tonnes of a nominated 15 000 tonne cargo of butane, the Braefoot Bay area was subjected to an unusually violent squall. This squall produced a veering westerly wind with gusts in the order of 80 knots (92 mph) superimposed on a mean wind speed that reached 62 knots. The resulting additional loading on the mooring system was resisted only by the forward backsprings. The winch brakes for these were overcome and the ship began to move ahead along the berth driven by the wind. As she gathered momentum the loading arms reached their envelope limits and successfully disconnected with no spillage of cargo. The remainder of the mooring lines failed one by one as the load came upon them sequentially.

Havkong began to swing under the influence of both the wind and the last of the moorings and drifted eastwards, broadside to the wind. She cleared a ship on the other berth, which was loading ethylene, by approximately 20 metres. About eight minutes after breaking away her engine was ready for use and this was used to keep the ship in the deep-water channel as she drifted downwind while the anchors were prepared. She was eventually brought to anchor approximately one mile east of the berth. A pilot boarded her to assist and tugs arrived. With tug assistance the ship was manoeuvred out into the main channel and then to a designated anchorage. The incident was declared over at 22:55 hours when Havkong anchored in Kirkcaldy Bay.

The available evidence leads to a conclusion that Havkong grounded lightly, probably on two occasions, during the incident. However, no damage was done to the hull and her cargo containment remained intact. There were no injuries on board and no spillage of cargo. Damage to the ship was limited to some deformed rails near the manifold and minor damage to one manifold line. As a result of the ship’s movement there was minor damage to the access gantry, loading arms and navigation light on the jetty.

The inadequacies in Shell Expro’s system for dealing with high wind speeds did not in themselves contribute to the incident. However, they led to the highly unsatisfactory situation that when the Havkong broke free from its moorings, terminal staff were caught by surprise with the ship still loading normally, despite wind speeds above the limits specified for stopping loading and disconnecting.

KEY ISSUES:
• EMERGENCY RESPONSE / SPILL CONTROL
• CONTROL ROOM DESIGN
• OPERATING PROCEDURES
• DESIGN CODES – JETTIES

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