Entry & progression
A modern superyacht is a floating power station with a hull around it. Understand that sentence properly and you understand both why the ETO exists on these boats and why the certificate's threshold is written the way it is.
Now take a yacht of the same length. It is carrying a fraction of the deadweight and it does not need to move a cargo, so the main engines are comparatively modest. But it is carrying an electrical load that the merchant ship would find absurd.
Where a yacht's electricity goes
| Load | Why it is so large |
|---|---|
| HVAC | Every space conditioned, continuously, in the tropics. Chillers, pumps, air handlers — usually the single biggest consumer aboard. |
| Hotel load | Galley, laundry, refrigeration, lighting, lifts, spa, pool, sauna. A small hotel, running at full occupancy, at sea. |
| Audiovisual and IT | Screens, servers, amplifiers, network, satellite. Never switched off, and intolerant of a poor supply. |
| Stabilisers | Zero-speed stabilisers work hardest at anchor — the load does not go away when the engines stop. |
| Thrusters | Bow and stern. Brief, brutal, and increasingly electric. |
| Hydraulics | Passerelle, tenders, cranes, hatches, anchors. |
| Hybrid / diesel-electric drive | Where fitted, propulsion itself becomes an electrical load on the same busbars. |
Add it up and the picture inverts. The installed electrical generation capacity on a large yacht is frequently out of all proportion to its propulsion power, because the owner's expectation is that the vessel performs identically alongside, at anchor and under way — and everything that delivers that expectation is electrical.
And this is exactly what the certificate measures
TIP — The ETO threshold is the one AMSA figure a yacht is built to clear The ETO sea-service requirement is stated on vessels with total installed electrical generation capacity of at least 750 kW. Not propulsion power. Every other kilowatt figure in the Australian engineering system — 375, 400, 500, 750, 1500, 3000 kW — refers to propulsion.
A yacht that would never clear a 750 kW propulsion threshold can clear a 750 kW generation threshold comfortably. That is the whole reason the ETO is the yacht certificate of the AMSA engineering system, even though the word 'yacht' appears nowhere in Marine Order 72.
Do not assume — measure
'Many yachts clear it' is not 'your yacht clears it'. Before you plan sea service against this threshold, get the vessel's installed generating capacity from the electrical load analysis, the generator nameplates and the single-line diagram, and get it in writing from the company. The figure is the sum of installed capacity — it is a documented number, not an estimate, and you should be able to produce the document.
CAUTION — Capacity is necessary; acceptance is AMSA's There is no primary AMSA statement confirming that superyacht service is accepted toward international engineering certificates. AMSA has express discretion to discount service it considers of little or no relevance, and states that service on vessels which spend considerable time in port will not be accepted.
A yacht that sits on the dock for eight months of the year is precisely what that provision describes. Clearing the capacity threshold on paper does not settle the question. Ask AMSA, in writing, before you build a plan on it.