Please help me decode something here. Requirements for STCW OICNW are governed by multiple CFRs:
OICNW 500 GT or more is governed by 46 CFR 11.309
OICNW less than 500 GT Oceans is governed by 46 CFR 11.319
OICNW less than 500 GT NC is governed 46 CFR 11.321
For 500 GT NC, sea service required is 720 days - none of it required under the supervision of an officer holding an STCW endorsement.
For greater than 500 GT, 1080 days and you need to provide evidence of having performed, during the required seagoing service, bridge watchkeeping duties under the supervision of an officer holding the STCW endorsement as master, chief mate, second mate, or OICNW, for a period of not less than 6 months.
But for OICNW 500 GT OCEAN, the requirement is 1080 days AND provide evidence of having performed during the required seagoing service, bridge watchkeeping duties, under the supervision of an officer holding the STCW endorsement as master, chief mate, or OICNW, for a period of not less than 6 months. The Coast Guard will accept service on vessels as boatswain, able seaman, or quartermaster while holding the appropriate deck watchkeeping rating endorsement, which may be accepted on a two-for-one basis to a maximum allowable substitution of 3 months (6 months of experience equals 3 months of creditable service);
The bit in bold italics has me confused - and note that this wording does not appear in the unlimited option. If two-for-one time is granted up to 3 months for serving as a rating (boatswain, AS, or quartermaster), what endorsement does CG expect to be held for the other 3 months?
Do they expect the remaining service to be done under an officer endorsement? How is that possible if OICNW is the bottom rung of the ladder for these endorsements?