Crosby Group receives order for custom pulleys for offshore drillships

The Crosby Group, a leading manufacturer of rigging, lifting and material handling equipment and supplies, has received a large order of custom 115t Safe Working Load (SWL) pulleys for overhauling towers. drilling a fleet of ships.

These towering derricks reach 65m above the deck of ships that have been modified to drill oil and gas wells. These drillships are equipped with a drilling derrick; the sheaves provide cable guidance for lifting the drilling equipment up and down the tower (or derrick).

Roger Øvstetun, Engineering Solutions Manager at The Crosby Group, said: “The Crosby Group offers a variety of sheaves which have several advantages, meeting the requirements of this application and many others. This enables The Crosby Group to provide competitive solutions for a multitude of applications. We evaluate each incoming request to ensure that we provide the best type of solution. In this case, the ductile casting solution was the right choice for the application.

For this latest project, the pulleys each weigh 1.5 t and comply with EN 1563, DNV and other relevant standards. With an outside diameter of 2273mm, the pulleys will be used with a 70mm diameter wire rope to raise and lower the drilling equipment.

The vessels in service each have a drilling depth of nearly 12,200 m (approximately 40,000 ft) and typically work in water depths of 3,650 m (approximately 12,000 ft). They needed a strategic overhaul, due to shortcomings of a previous solution, which needed to be completed over a period of time.

Øvstetun said, “Our extensive know-how on different pulley designs, brands and types sets us apart. Given the scale of these operations, we had to commit to delivering sheaves that were geometrically optimized to manage stresses and capacity. They are made from a proven material that has been optimized over time.

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