Entry & progression
Entry: none — this is the unit that governs the whole subpart. Get this wrong and every threshold in the course goes wrong with it.
WARNING — "3,000 GT" has no engineering meaning Deck STCW endorsements are titled by gross tonnage — 500 GT, 3,000 GT. Engineering STCW endorsements are titled "on vessels powered by main propulsion machinery of [X] kW/[Y] HP propulsion power." Gross tonnage appears nowhere in 46 CFR 11.325, 11.327, 11.329, 11.331, 11.333 or 11.335. The engineering counterpart of 3,000 GT is not 3,000 GT. It is 3,000 kW / 4,000 HP, and it is measuring a completely different thing.
A yacht engineer coming from the deck side, or from a European system where everyone talks tonnage, will reach for GT by reflex. Break the reflex now. When you are working out which STCW engineering endorsement a vessel demands, the only number that matters is the propulsion power in kilowatts.
What counts as propulsion power — 46 CFR 10.107, verbatim
"Propulsion power means the total maximum continuous-rated output power of the main propulsion machinery of a vessel determined by the manufacturer, in either kilowatts or horsepower, which appears on the ship's Certificate of Registry or other official document and excludes thrusters and other auxiliary machinery."
Read the last five words again
Excludes thrusters and other auxiliary machinery. On a modern yacht that exclusion is enormous. Your gensets do not count. Your bow thruster does not count. Your stern thruster does not count. Your hydraulic power packs, your zero-speed stabilisers, your shaft generators driving hotel load — none of it counts. The number is the mains, at maximum continuous rating, as the manufacturer declared them and as they appear on the ship's papers.
TIP — The yacht consequence A large yacht can carry a genuinely enormous electrical plant and still sit below 3,000 kW of propulsion power. Two 1,200 kW mains, four 200 kW gensets, two 150 kW thrusters — the propulsion power is 2,400 kW. Not 3,700. The vessel is in the 750–3,000 kW band, and the management endorsements it demands are the III/3 pair, not III/2.
This cuts both ways. It can put a big-feeling boat in a smaller regulatory box than the crew expect — and it means an engineer who logs that time is logging sub-3,000 kW service, whatever the boat looks like from the dock.
The HP↔kW pairs are regulatory, not arithmetic
The CFR writes every threshold as a pair: 750 kW / 1,000 HP. 3,000 kW / 4,000 HP. 7,500 kW / 10,000 HP. Run those through a calculator and they do not quite work — 3,000 kW is about 4,023 horsepower in physics.
It does not matter, because 46 CFR 10.107 defines the conversion: "Kilowatt or kW means 1⅓ horsepower"; "One horsepower equals 0.75 kW." By regulation, 3,000 kW is 4,000 HP. The pairing is a legal definition, not a measurement.
CAUTION — Do not "correct" the Coast Guard's arithmetic Quote the pairs exactly as the CFR writes them — 750 kW/1,000 HP and 3,000 kW/4,000 HP. An applicant who converts the numbers himself and submits a service letter claiming 4,023 HP has invented a figure that appears in no regulation. Use the pairs. They are the law.
Where the number actually comes from
Not from the engine plate, and not from the chief's memory. 10.107 says it is the figure "which appears on the ship's Certificate of Registry or other official document." That is what the NMC will look at. Before you write a sea service letter, go and read the paper.