46 CFR § 131.570
Quarterly inspections
April 15, 2021
(a) Each apparatus that controls a lifeboat winch, including motor controllers, emergency switches, master switches, and limit switches, must be inspected once each 3 months.
(b) The inspection must involve the removal of drain plugs and the opening of drain valves to ensure that enclosures are free of water.
(c) The date of the inspection required by this section and the condition of the equipment must be entered in the vessel's logbook.