| CPC B66D 1/40 (2013.01) [G01S 17/88 (2013.01)] | 16 Claims |

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1. A winch drum monitoring device that monitors a state of a winch drum, the device comprising:
a phase detector configured to detect a phase of the winch drum;
a distance detector configured to detect a distance to the winch drum or a distance to a wire rope wound around the winch drum; and
a phase determination portion for detecting a specified phase,
wherein the phase detector detects the phase of the winch drum by detecting the phase determination portion.
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