Entry & progression
Entry: none beyond L1.2. Progression: route is the axis that decides whether a DDE is any use to you at all. If your boat crosses oceans, this is the most important lesson in Module 1.
WARNING — Two of the three tiers cannot go to sea on oceans. At all. 46 CFR 11.501(c). DDE < 1,000 HP and DDE < 4,000 HP are near-coastal or inland ONLY. Not oceans. Not "oceans with a limitation." Not at all.
Only DDE-Unlimited carries any waters. If you intend to be the engineer on a boat that crosses, the lower two tiers are not a stepping stone toward that job — they are a different job.
| DDE tier | Route | Tonnage |
|---|---|---|
| DDE < 1,000 HP / 750 kW | near-coastal or inland only | < 500 GRT |
| DDE < 4,000 HP / 3,000 kW | near-coastal or inland only | < 500 GRT |
| DDE — Unlimited | any waters | < 500 GRT |
Three axes, not one
A US engineering credential is scoped on three independent axes: route (oceans, near-coastal, inland, Great Lakes), tonnage (here, < 500 GRT), and propulsion power (the HP/kW tier). Your authority is the intersection of all three, and the tightest one governs. A DDE-Unlimited on a 400 GRT yacht with 6,000 HP of mains crossing the Atlantic is inside all three. Move any one of those numbers and the answer changes.
Mariners routinely think about power and forget route. Route is the one that strands you in Gibraltar.
What this means for a yacht programme
Work backwards from the boat's actual itinerary. A Florida-to-Bahamas charter boat, a New England summer programme, an inland or coastwise workboat — the lower tiers do that work. A boat with a Med season and a Caribbean season has an ocean between them, and only DDE-Unlimited answers for it. That is 3 years of engineroom service, 18 months of it as QMED, and age 21. There is no shortcut and no ocean endorsement to bolt onto the lower tiers. You serve the time.
When STCW attaches on top
The national endorsement is one system; STCW is another, and it bites on geography and size. 46 CFR 15.1103(a): "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."
And "seagoing vessel" is defined at 10.107 as "a ship that operates beyond the boundary line specified in part 7." That is a geography test, not a size test. Where the boat goes, not how big she is.
The relief runs the other way too. 11.323(c): "An engineer officer who does not hold an STCW endorsement may serve on seagoing vessels propelled by machinery of less than 750 kW/1,000 HP, the vessels specified in § 15.105(f) and (g), and vessels operating on the Great Lakes or inland waters of the United States." Below 750 kW, no STCW engineer endorsement is required at all.
There is also a deemed compliant class (15.105(g), 11.301(g)) for 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.
CAUTION — The national/STCW interaction is fact-specific — take the vessel's documents to the NMC Route, tonnage, propulsion power, flag and itinerary all move the answer, and a DDE-derived STCW certificate carries its own footnoted cap (see Lesson 4.3). Do not resolve this from a forum post or a colleague's recollection. Pull the current checklist for your endorsement from the National Maritime Center and take the boat's Certificate of Registry, COI or tonnage document with you.