July 14, 2011

Docking with fiber mooring lines takes 30-90 minutes instead of 240 minutes

COSCO Dalian (a subsidiary of China Ocean Shipping Group) evaluated two mooring lines made with Dyneema®, the world’s strongest fiber aboard one of its VLCC (Very Large Crude Container) vessels

In January 2008, the COSPEARL LAKE became the world’s first VLCC vessel to be 100%
equipped with mooring lines made with Dyneema®. There were, in total, 22 lines brought on board. Twenty were installed in winches for operation. The other two were stored as spares. Each line had a nominal diameter of 46 mm, a net length of 280 meters and was rated MBL 1300 kN.

All the strength, a fraction of the weight… adds up to more speed.

With a steady increase in the length and capacity of oil and LNG carriers, and the trend towards mooring in more exposed conditions, greater loads are placed on mooring lines. When conventional steel lines are made stronger, they become even heavier and more difficult to handle. The connecting shackles between steel wire and nylon tail alone can weigh up to 90 kg.

Docking and undocking times for the COSPEARL LAKE have been significantly reduced with the new set of mooring ropes. With steel wire lines, the typical docking time is approximately 240 minutes. By using the mooring lines made with Dyneema®, the crew is able to dock in less than 90 minutes.

“If steel lines were used, only the preparation would need two and half hours of hard work by the deck crew,” said Mr. Wang Lije, boatswain of the vessel. Preparation of mooring lines consists of pulling lines out of the winches to their corresponding fairleads. The lines made with Dyneema® have greatly relieved the crew of the hard and dangerous work of handling heavy, greasy steel wire and tail shackles. Captain Tang put it this way: “In fact, there is no need to prepare mooring lines made with Dyneema before docking. You just pull them out from the winch and start docking.” On July 7, 2008 at Qingdao terminal, Boatswain Wang said, “Today we created a new docking record for a VLCC by using mooring lines made with
Dyneema® -- 32 minutes!”

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