Difference between oiler and wiper?

What is the difference between oiler and wiper? Is oiler defined anywhere for COI purposes?

Take with a grain of salt.

A wiper is a entry level position identified on the mariners MMC. It required no shipboard experience necessary. Oiler is a QMED qualified rating. The position requires at least 6 months in an engine room and testing.


I’m not aware of a cite where it’s defined, probably because it’s assumed that it doesn’t have to be, it’s someone holds an MMC endorsement as QMED-Oiler.

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What is the difference between a Messman and a Messboy?



Her indoors always wanted to meet a Donkey Greaser.

Take with a grain of salt.

I have seen the number of Oilers required placed on the vessel COI form CG 841 which is a separated from QMED positions. The numbers are determine by OCMI and their inspection regulations.


I’ll tell you another reason this comes up. A lot of the old school mudboat chiefs that were running a two man engine room would call their assistant an oiler even if they only had a z card with the entry level rating of wiper.


That seems reasonable except that the COI form also has an item listed as Qualified Member Engineer(sic?). This begs the question what is the difference between this guy and an Oiler?

It’s not clear what your question is or if you are familiar with the engine department positions. What exactly does your COI say for manning?

On the chance that you are not familiar with the positions…:

CFRs define QMED (using the term “define” loosely because as Mr. Cavo alluded to this is not a definition found in the Definitions section but an explanation found in the General section):

§ 12.501 General requirements for a qualified member of the engine department (QMED).

(a) General. A qualified member of the engine department is any person below officer and above the rating of coal passer or wiper, who holds an MMC or MMD endorsed as QMED by the Coast Guard.

Wiper is entry level, and may not even be required on the COI. To get a QMED you need sea time and pass the exams for one or all of the QMED ratings.

(b) Categories.

(1) Each QMED rating must be endorsed separately, unless the applicant qualifies for all QMED ratings, in which case the endorsement will read “QMED—any rating.” The ratings are—

(i) Fireman/Watertender;
(ii) Oiler;
(iii) Junior engineer;
(iv) Electrician/Refrigerating engineer; and
(v) Pumpman/Machinist.

If you want to know what subjects you need to pass for the Oiler endorsement its here.

So the difference between an Oiler and a Wiper is that an Oiler has a certain amount sea time and passed exams to obtain a qualification endorsement, and a Wiper has not.

What’s the difference between an AB and an OS?

About $200 a day…

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ship engr: a jr eng. includes all 7? endorsements. (used to be 7 I believe) I started off getting pumpman, oiler, machinist etc. but after about 3 of those I got the Jr. eng. endorsement, It includes all of those but obviously took a bit more studying … It got me a job of pumpman on the Chevron Mississippi and i think mfow Cape Fear but that’s about it. of course it took a “BIT” longer to get 3ae !!

That’s the second part I block-quoted above. There are currently five individual ratings with Junior Engineer being one of the five (Not sure if you can split ones like Elec/Refer to just Elec or just Refer). If you qualify for all five then your MMC will be endorsed as “QMED-Any Rating”.

It is a little crazy though how Jr Engr exam subjects cover almost every other one of the ratings subjects. If you have the knowledge for Jr Engr you’d probably be able to pass them all and get Any Rating.

To be honest I’ve only seen Junior Engineers at MSC and they actually still post for the position of Unlicensed Junior Engineer, separately from Engine Utility (oiler), Pumpman, and Refer Engineer.

There’s 5 now. Pumpman and machinist were combined in 2014, as were electrician and refrigerating engineer.

well, whadd’ya know. that’s progress i suppose !! I’m proud to say i never spent a day in the deck dept. i could make accidental knots no one could un-do.


If you can’t undo it, it is not a knot.
It is not a splice, it is not a weave, it is not a fist of any description.
Just a ball of string that you found in the kitchen drawer.
Next to the spare batteries.

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I think that person is called an andrologist.

Funny. So it would seem that Oiler = QMED (oiler), while the “Qualified Member Engineer” must be the QMED with multiple endorsements.

There is no OS vs AB dilemma as both of these positions appear on the COI form.

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Whatever happened to the QMED Any Rating?