Section 15.404 - Requirements for serving onboard a vessel(a)Ratings Forming Part of a Navigational Watch (RFPNW). Each person serving as an RFPNW on a seagoing vessel of 500 GT or more, subject to the STCW Convention (incorporated by reference, see § 15.103 of this part), must hold an STCW endorsement attesting to his or her qualifications to perform the navigational function at the support level.(b)Able seaman. Each person serving as a rating as able seaman on a U.S. flag vessel must hold an MMC endorsed as able seaman, except that no credential as able seaman is required of any person employed on any tug or towboat on the bays and sounds connected directly with the seas, or on any barges except seagoing barges or tank barges. Each person serving as an able seaman on a seagoing vessel subject to the STCW Convention must also hold an STCW endorsement as able seafarer-deck.(c)Ratings Forming Part of an Engineering Watch (RFPEW). Each person serving as an RFPEW in a manned engineroom or designated to perform duties in a periodically unmanned engineroom, on a seagoing vessel driven by main propulsion machinery of 1,000 HP/750 kW propulsion power or more, must hold an STCW endorsement attesting to his or her qualifications to perform the marine-engineering function at the support level.(d)Qualified Member of the Engine Department (QMED).(1) The holder of an MMD or MMC endorsed with one or more QMED ratings may serve in any unqualified rating in the engine department without obtaining an additional endorsement.(2) A QMED may serve as a qualified rating in the engine department only in the specific ratings endorsed on his or her MMD or MMC.(3) Persons serving on vessels subject to the STCW Convention as junior engineer, pumpman/machinist, or electrician/refrigeration engineer must also hold an STCW endorsement as able seafarer-engine.(e)Lifeboatman. Every person assigned duties as a lifeboatman must hold a credential attesting to such proficiency. Persons serving on vessels subject to the STCW Convention must also hold an STCW endorsement in proficiency in survival craft and rescue boats other than fast rescue boats (PSC).(f)Lifeboatman-limited. Every person assigned duties onboard a vessel that is not required to carry lifeboats and is required to employ a lifeboatman must hold an endorsement as either lifeboatman or lifeboatman-limited. Persons serving on vessels subject to the STCW Convention must also hold an STCW endorsement in proficiency in survival craft and rescue boats other than lifeboats and fast rescue boats-limited (PSC-limited).(g)Fast rescue boats. Every person engaged or employed in a position requiring proficiency in fast rescue boats must hold an endorsement attesting to such proficiency.(h)Entry level. Every person employed in a rating other than able seaman or QMED on a U.S. flag vessel on which MMCs are required must hold an MMD or MMC endorsed as wiper, ordinary seaman, steward's department, or steward's department (F.H.).(i)Person in charge of medical care. Every person designated to take charge of medical care onboard vessels subject to the STCW Convention must hold an MMD or MMC endorsed as person in charge of medical care.(j)Medical first-aid provider. Every person designated to provide medical first aid onboard vessels subject to the STCW Convention must hold an MMD or MMC endorsed as medical first-aid provider or a deck or engineer officer endorsement.(k)GMDSS radio operator or maintainer. Every person responsible for the operation or shipboard maintenance of GMDSS radio equipment onboard vessels subject to the STCW Convention must hold an MMD or MMC endorsed as GMDSS radio operator or GMDSS radio maintainer, as appropriate.