46 CFR § 118.320 - Firehoses and nozzles.
(a) A fire hose with a nozzle must be attached to each fire hydrant at all times. For fire hydrants located on open decks or cargo decks, where no protection is provided, hoses may be temporarily removed during heavy weather or cargo handling operations, respectively. Hoses so removed must be stored in nearby accessible locations.
(b) Each hose must:
(1) Be lined commercial firehose that conforms to UL 19 “Standard for Safety for Lined Fire Hose and Hose Assemblies” (incorporated by reference, see § 114.600 of this chapter), or hose that is listed and labeled by an independent laboratory recognized by the Commandant as being equivalent in performance;
(2) Be 15.25 meters (50 feet) in length and 40 millimeters (1.5 inches) in diameter; and
(3) Have fittings of brass or other suitable corrosion-resistant material that comply with National Fire Protection Association (NFPA) 1963 “Fire Hose Connections,” or other standard specified by the Commandant.
(c) Each nozzle must either:
(2) Be of type recognized by the Commandant as being equivalent in performance.