DRUM LAYERS, SURFACE RESISTANCE, DEPTH AND SLOPE

ONE of the common misconceptions regarding winches is that the maximum rated winch capacity is available any time the winch is hooked up. Unfortunately, this is false. Winch capacity is in fact determined by the number of layers of cable wrapped on the winch drum.

While line pull per layer is an often quoted specification, given an empty winch drum affords the smallest diameter and a full drum the largest, it’s easy to presume that as each layer of rope rolls onto the drum, the winching effort increases proportionally.

All winches are maximum rated with an empty drum, while their (mathematical) rating drops dramatically to almost half when full. Yep, a 9500lb winch is only rated at 9500lb when the drum is on its first layer, yet is only (mathematically) rated at about half that (about 4500 to 5500lb) with four or five rope layers rolled onto the drum. Theoretically this is correct, but in reality it doesn’t exactly work like the pretty diagrams (that are bandied about with nice neat layers of rope) suggest.

Synthetic rope is somewhat flexible (can be distorted and flattened) and the rolls can never be totally pushed up hard against each other as the winch drum rolls in. We found the rope would either mesh into the previous roll, providing similar drum diameters (ratios); or would bunch up on one side for a few rolls, effectively raising drum diameter and ratios.

While you can, at times, help to guide the rope in for a neat roll by pulling the rope sideways from the winch body, you are putting yourself directly in the line of fire if something fails and flings back.

The neater the rope is kept while pulling in, and the straighter the pull is in line with the vehicle, the better the chances are of keeping an even drum roll.

Ideally, any winch pulling a stuck vehicle should be using the first or second roll on the drum to return the best load ratings and maximum pulling power.

Unfortunately, this is not always practical in real life; your tree or winch anchor point will (almost) never be perfectly positioned, so you’ve just gotta use what you have available, or use a double line pull to get more rope of the drum to start with.

Every winching exercise must also consider surface resistance, slope and depth. Resistance of the ground you are stuck in; deep fluffy sand, gloopy wet mud and rocky ledges are all going to add higher winching resistances than a loose, gravelly track. So too will any gradient above dead level.

The depth of the poo you are stuck in will sky rocket your winch’s inability to do its job – the deeper the shit you’re stuck in, the more likely you are to remain stuck in said shit.