Entry & progression
Entry: none. Progression: this lesson tells you whether you need any of this at all. The trigger is in Part 15, not Part 11. Most people never read it.
46 CFR 15.1103(a), verbatim
WARNING — The trigger — read the OR "Onboard a seagoing vessel of 500 GT or more, driven by main propulsion machinery of 1,000 HP/750 kW propulsion power or more, or on an international voyage beyond the boundary line… no person may serve in a position requiring a person to hold an STCW endorsement… unless the person serving holds an appropriate, valid STCW endorsement."
That is two triggers joined by or, not one compound test. Trigger one: seagoing, 500 GT or more, and 750 kW or more. Trigger two: an international voyage beyond the boundary line. Either one is enough.
"Seagoing" is a geography test, not a size test
46 CFR 10.107: a seagoing vessel is "a ship that operates beyond the boundary line specified in part 7." That is it. Not big. Not ocean-going in the colloquial sense. Beyond the boundary line — a set of drawn lines running across bays and river mouths, listed vessel by vessel and coast by coast in 46 CFR Part 7.
So a 700 GT yacht with 1,500 kW of mains that never leaves an inland bay is not seagoing and does not trip trigger one. Take the same yacht two miles offshore and it does. The vessel did not change. The geography did.
The ratings triggers are different
Note this, because it catches people. The RFPEW and Able Seafarer-Engine triggers at 15.1103(d) and (e) bite at 750 kW / 1,000 HP with no gross tonnage threshold at all. The officer trigger has a 500 GT element; the ratings trigger does not.
The deemed-compliant vessels — "no further obligation"
46 CFR 15.105(g) and 11.301(g) carve out a class of vessel that the Coast Guard treats as already meeting the convention: small vessels engaged exclusively on domestic, near-coastal voyages — subchapter T and K small passenger vessels, vessels of less than 200 GRT other than subchapter H, and uninspected passenger vessels. The regulation's own phrase is that the mariner has "no further obligation" under STCW.
| Situation | STCW engineer endorsement required? |
|---|---|
| Seagoing, ≥ 500 GT and ≥ 750 kW | Yes |
| International voyage beyond the boundary line | Yes |
| Propulsion machinery < 750 kW / 1,000 HP | No — 11.323(c) |
| Great Lakes or inland waters | No — 11.323(c) |
| 15.105(f)/(g) vessels, domestic near-coastal only | No — "no further obligation" |
CAUTION — Check the boundary line before you assume The boundary line is drawn in 46 CFR Part 7 and it is not intuitive — it cuts across harbours and estuaries in ways that surprise people who have run the same route for years. If a voyage sits anywhere near it, do not guess. Read Part 7 for your waters, and put the question to the OCMI.