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 MIL-HDBK-1038
intended primarily for installation aboard barges and floating cranes for mooring
and re-positioning along the piers. These mechanisms are designed to marine
industry specifications for service aboard seagoing vessels. They should be used
at their rated capacities.
3.3.1
Capstans. Capstans have a smooth drum on a vertical axis, with its
bottom end connected to the drive mechanism, and its top unobstructed. Unlike
hoists, there is no mechanical anchor for the rope, the drum develops sufficient
friction with the mooring line (non-metallic rope) from a number of manually wound
"dead wraps" to begin pulling the loaded end of the rope. The unloaded end is
handled manually as it pays off the drum and is coiled on the deck. The number of
friction producing dead wraps remains constant during the hauling process.
Capstans are normally powered by electric motors.
3.3.2
Windlasses. Windlasses are a modification of capstans, in that, the drum
is replaced by a pocketed and slotted wheel (wildcat) that grabs a chain, as it
makes half a wrap around it. The unloaded end of the chain is collected on the
deck. Windlasses are used on barges and floating cranes primarily for dropping
and raising anchors. Windlasses are normally powered by electric motors.
3.3.3
Winches. Winches are identical to single reeved hoists, except that the
wire rope live end is routed for hauling, rather than lifting the load. The wire
rope drum may be grooved (for single layer spooling) or smooth (for multi-layer
spooling). Winches with smooth drums can also be used for hauling mooring lines
or chains. Winches are available with either electric or hydraulic motors.
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