C=the angle between the boom and the boom hoist cables
DLT=measured boom deadline tension
Wt=total weight including empty blocks and 1/2 the boom weight
BW=1/2 the empty boom weight
ML=number of lines strung on the main blocks
BL=number of lines strung on the boom hoist; and
H=the angle between the boom hoist lines and the main hoist fast line
W=actual hook load (and the weight of the empty blocks).