Drums should be large enough to properly wind the rope using the smallest number of layers. Drums having a diameter 24 times the rope diameter should be considered as a minimum for proper spooling.
Multiple layers on a plain (smooth) faced drum crush the first layer of rope much more than on a grooved drum. The grooved drum is also recommended to provide better spooling
The correct lay for each winding direction. The direction of winding on a drum (overwind or underwind) is determined by standing behind it and looking toward the direction of rope travel.
When winding only one layer on a smooth drum, attaching right and left lay ropes as shown in the drawings below will give the best service.
Multiple Layer Winding
When a rope winds in the first layer across the face of a drum, it usually forms a uniform helix. When spooling on a smooth drum, the first layer helix serves as the drum lagging for succeeding layers. For continuous smooth spooling, the first layer should act as a dead layer and not be removed from the drum during normal use. On grooved drums, the grooves control the rope spooling on the first layer, making all the rope usable in the system. However, various codes do require a minimum of two to six dead wraps, depending on the application.
After spooling the first layer, the rope rides up on the last turn and starts winding back across the face of the drum, but falls into the depression of the successive turns of rope on the first layer.
Advancing across the drum on the second layer, the rope, following the depressions of the first layer, actually winds back a turn in each revolution of the drum. It must then cross over two depressions of the first layer to have a net advance of one turn per revolution.
This cross over is unavoidable on the second and succeeding layers. Severe punishment of the rope results due to abrasion of the adjacent turns against each other and the crushing from the next layer above at these points. Parallel and counter-balanced, grooved-controlled, crossover drums minimize this condition.
If scrubbing (adjacent wrap contact) is a major problem, it can be reduced by applying the “winding direction rules” to the heaviest worked layer instead of the first layer as shown. To accomplish this, the first layer may or may not be spooled according to the rule as well.