Engineering Data

Maximum Line Pull

This is the maximum dead-weight the winch could lift off the ground with a single line on the first layer of wire rope on the drum. They are not suitable for vertical lifting.

Winching Principles

You need a winch to be powerful enough to pull your vehicle and overcome the added resistance caused by obstacles like water, mud, snow, sand or steep hills.

As a general guide you need a winch with a maximum line pull of at least 1.5 times greater than the gross vehicle weight.
There are three factors that have influence on the line pull effect required to recover the vehicle. The values and calculations in this section are approximate and are for reference only.

Gross Vehicle Weight (Wt): Contains a vehicle weight and the weight of the supplies and equipments carried.

Surface Drag (S): The characteristics of the terrains or surface to be traversed.

Surface Type	Metal	Sand	Gravel	Soft Sand	Mud	Marsh
Surface Drag (S)	0.15	0.18	0.20	0.22	0.32	0.52

Gradient Resistance (G): The incline of grade or slope on which the vehicle is being moved.

Gradient	5%	10%	20%	30%	50%	70%	100%
Angle (ref.)	3°	6°	11°	17°	26°	35°	45°
Gradient (G)	0.06	0.11	0.2	0.3	0.44	0.58	0.71

Combining the gross vehicle weight (Wt), the type of the surface to be traversed (S), and the gradient to overcome (G), use the following formula.

Effect required to recover the vehicle = ( Wt X S ) + ( Wt X G )