2:1 Purchase

Note: be careful to double check shackle jaw width related to drum/swivel spindle. For a halyard, it is deadended on the mast and then runs around the bearing surface of the 2:1 shackle/block and then into the halyard sheave and down to deck level. For a 2:1 Tackline, the line is deadended at deck level and then up around the Frictions sheave and then down to a block on the deck and back to a jammer cleat / winch for tensioning.