Wire rope spooling technology

These problems were addressed by Frank L. LeBus Sr., a supplier of drilling equipment to the oilfields of Texas, USA, who in 1938, patented the use of a groove bar on hoisting drums to guide the spooling of rope.

Examples include: With the parallel groove system, rope wear is considerably reduced in multilayer spooling.

With parallel grooving it is possible to calculate the exact forces that the rope imposes on the drum because the spooling is controlled.

Cross winding is reduced to approximately 20% of the circumference of the drum, and 80% remains parallel to the flanges in the inner layer rope groove.

The anchor winches on Saipem's Semac 1 pipe laying barge, for example, each hold 2,800 metres of 76mm (3 inch) diameter wire rope in 14 layers.

Saipem's Castorone, the world's largest pipe laying vessel uses a wire rope that is 3,850m long and 152mm in diameter.

With all type of drums, the rope is subject to a fleet angle which impacts on its behaviour and affects lifespan.

The fleet angle compensator (FAC) is driven by the movement of the wire rope as it goes through the crossover sections of the drum.

The lateral movement of the housing is generated by a chain drive sprocket ratio between drum and lead screw, as shown in the image.

Grooving systems for multilayer spooling can be carved onto steel shells that are mounted onto old drums, by either bolting or welding, as an outer sleeve.