Cable Crane Racking lights guide
The image is courtesy of Tom Dunn, Huntly who had a small collection of old forestry and timber tools.
Brings back the memories when marking out racks for the cable crane extraction of thinnings in forests on the west coast of Scotland. Rackways of lengths up to 300 yards had to be straight to ensure the cables ran down the centre of the rack from the spar tree at the end to the tractor winch at the other. Attempting to mark a straight rack in unbrashed Sitka spruce first thinning was always a daunting task. The line of ranging rods soon ran into the middle of a tree and impossible to see through. Carefully using the same compass bearing the line could be accurately continued on but this was always very difficult on steep slopes. The compass had to be kept level and one had to peer upwards through the vertical hair line amid a sea of branches and roughly brash a line stage by stage with the axe to see any distance.
The principle of the lights rested on the chance that if the central white light was blocked by a tree or trees the chances were that either one of the side lights operated by switch from a central battery would take you through past the obstructions. In reality the equipment was cumbersome in unbrashed spruce and the lights were really not bright enough to counter the gloom and partial visibility – no LEDs in those days! Note the colours seem to be in ship shape order – red for port and green for starboard.
Any tales of using this device would be interesting indeed.
Picture added on 28 September 2018 at 21:43