Handbook of Winching Techniques

THE THEORY OF WINCHING

The most important aid to successful winching (after the winch) is the pulley block), which can be used to increase the

pulling power of the winch or for indirect pulls. Pulley blocks can be used in two modes. (a) attached to the load and

(b) secured to an anchor point.

The anchor point, when used, must be secure, using a tree, another vehicle or any firm structure to which a pulley block

can be attached with a chain or stout rope. Figs 1- 4 show typical examples where a pulley block can be used to

advantage, based on a winch line pull of 1000 lbs.

Fig. 1 Vehicle self recovery using the pulley block attached to the anchor point for direct pull. In this instance the

vehicle becomes the ‘load’ and the actual pulling power on the vehicle will be 2000 lbs at half winch rope speed.

Fig. 2 Direct pull on load using the winch vehicle as the anchor with pulley block attached to the load. Actual pulling

power on load will be 2000 lbs at half winch rope speed.

Fig. 3 Indirect pull necessitated by obstructions or soft ground. Pulley block attached to load using a suitable anchor

point. Note the angled direction taken by the load and subsequent angle of rope feed-back on the winch drum (extreme

example shown). There may be unavoidable circumstances requiring this mode, though in general it is not

recommended unless applied in stages by moving the anchor point or vehicle to avoid sharp angled rewind on the

winch drum. The actual load pulling power and rope speed will depreciate with any increased angle between the ropes.

ACCESSORIES