Are engineers limited to ship size/tonnages?

I called the SIU academy to ask if the qmed comes with an unlimited endorsement but nobody seems to know anything about the industry (despite teaching future mariners, go figure). They said that limited and unlimited only applies to deck side. Is this true? If not, what is the credentialing for engineers who want to be able to sale on anything?

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With engine officer licenses it is usually divided by plant type and then horsepower. For example, my license states that I’m qualified to sail as CE motors, unlimited horsepower, 2nd assistant for gas turbines, unlimited horsepower and 3rd assistant for steam, unlimited horsepower.

Ratings don’t have tonnage limits.

Only AB ratings have “limited” and “unlimited” but those aren’t tonnage restrictions.

Chief Engineer of Motor, Steam, and Gas Turbine can sail in any capacity, any plant, any tonnage.

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It seems you know what you’re talking about. AB Limited and Unlimited are ranks. I thought they were limitations, like a CDL A and CDL B. Both are CDLs, but only one person can drive a combination vehicle. You feel me? From my research (asking elsewhere), Limited and Unlimited are close to “editions”. Like normal and rare, or standard retail and collector’s edition. Am I right so far?

No. One is inexperienced, one is experienced.

Limited = little to no experience
Special = some experience
Unlimited = a step away from levelling up to Bosun


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Bosun is just a job title. Still an AB.

Levels of AB License and Sea Service Requirements

  • AB Limited: This level requires 18 months of service aboard a ship weighing over 100 gross tons on the ocean or in U.S. waters.
  • AB Unlimited: The sufficient amount of sea time for an AB Unlimited endorsement is 1080 days.
  • AB Special: To qualify for AB Special, you need 360 days of experience aboard a ship on the ocean or U.S. waters.

Yes, but SIU requires one to be an AB Unlimited in order to be bosun.

Doesn’t have to be an AB. I have sailed with OS bosuns, although they had tons of experience as AB but could no longer meet vision requirements, so they only held OS (SUP)


An AB, but with keys :star_struck:

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With keys is a good description. They knew their shit.

QMED you just have series of endorsements all are unlimited horsepower and tonnage. Once you get to Engineering officers it’s different. DDE is limited to 500 tons, Assistant Engineer -limited / Chief Engineer-limited is limited to under 1600 tons. 3rd through 1st Engineer is unlimited. Then horsepower limitations are seperate on top of that. There is a Chief Engineer - limited crossover to 1st Engineer with enough sea time.

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There are a few different qmed ratings. If you hold all the ratings, which i can see being misconstrued as unlimited, its called in your mmc qmed-all ratings.

All engineer licenses can/may have a tonnage limitation and horsepower limitation.

A lot of people at the schools or in HR at the boat companies don’t understand the engine license scheme. Perfect example…i used to be a dde unlimited and all dde licenses are 500 grt licenses. A port engineer who was a younger fella, academy grad at a big tugboat company told me i didnt qualify for a job opening because i had a 500 grt limitation and he needed a dde unlimited. After attempting to explain to this dumb ass that the license he was requesting didn’t exist i finally gave up when he told me that when i upgraded to chief limited that license wouldnt be good enough either. Keep in mind i was applying for a harbor tug chief job. Last words were ‘so you are telling me you require an unlimited chief for a harbor tug job?’ He said ‘no, just dde unlimited but without a tonnage limitation.’ I then said good luck with that, have a nice day.

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The German merchant marine does have a qualification for Bosun. The ones I have meet on heavy lift vessels certainly knew their stuff.