[Fig. 110.] Double Burton (D), using but one rope, illustrates the possiblity of using it to greater mechanical advantage than would be possible in a six fold purchase. However, in this case the hoisting range is less than would be possible in a six fold purchase.
[Fig. 111.] Luff on Luff illustrates a common application of tackle to secure mechanical advantage. It will readily be recognized that the major tackle must be four times as strong as the other set if both are to be used anywhere near to capacity.
[Fig. 112.] Another Double Burton which also illustrates the possibility of combining two blocks in place of one, with the required number of sheaves.