Breast derrick means a derrick without boom. The mast consists of two side members spread farther apart at the base than at the top and tied together at top and bottom by rigid members. The mast is prevented from tipping forward by guys connected to its top. The load is raised and lowered by ropes through a sheave or block secured to the top crosspiece.
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Breastderrick means a derrick without boom. The mast consists of two side members spread farther apart at the base than at the top and tied together ...
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