Rope Installation & Training

Unless otherwise agreed with the customer, ropes are provided on reels which are designed for the purpose of transportation and storage. They can therefore bear a limited amount of pulling tension when unwinding the rope.

The direction of rope lay should be chosen in accordance to drum direction following the general rule “right hand pitch – left hand rope”, see image below. However this is often not applicable to heavy lifting devices, which usually requires the use of large size multilayer drums.

In this case, there are no special requirements and lay direction can be selected to facilitate the drum bedding, or optimized taking into account the rope layer that will be more frequently used during operations.

In order to ensure expected lifespan and performance, it is essential to have a tight bedding on the first winch drum layer, which is achieved by applying the correct installation tension. It should be at least the highest value between 2% of the rope MBF or 10% of rope SWL.

This tension can be easily achieved with commonly available tools for relatively small size ropes. 

In the case of large size rope a good practice could be to wind the rope using the maximum available back tension and obtain the correct value during the training stage.

Training is essential for any rope size to optimize rope lifetime and performance, as well as to stabilize its dimensions.

It involves the deployment of the full rope length, excluding the safety wraps, which must always remain on the drum, at least three times with any available payload: the weight of the rope will automatically generate the required back tension, diameter stabilization and torque factor reduction.

Safety wraps should be clearly identified to prevent unnoticed use.

A good spooling will show tight wraps and uniform rope arrangement in the cross over zone and up the last layers. This will reduce the risk of crushing, cut-in or early formation of broken wires.

Definitions:

WLL/SWL: Working Load Limit/Safe Working Load. WLL is the ultimate permissible load, assigned by the manufacturer of the item (crane). The SWL may be the same as the WLL but may be a lower value assigned by an independent competent person taking account of particular service conditions.

Working length: Working length is the portion of total length plus three wraps that has been used in operations since the last thorough examination.

Wraps/layers: A wrap is a single turn of a wire rope around the circumference of a drum. A layer is a number of wraps covering the horizontal distance between the drum flanges.

Cross-over zone: That portion of rope coincident with a crossing over of one wrap by another as the rope traverses the drum or rises from one layer to the next at the drum flange.