Difference between Mate OSV and 3M unlimited

I’m an AB on an OSV in the Gulf and I plan on becoming a mate.

I’ve been told the OSV mates license can be earned with 720 days while the 3M unlimited license can be earned at 1080 days.

I’m getting close to 720 and it would be cool to be able to sail as a mate quicker. Does anyone know if there is any difference in the actual exam that has to be taken?

I don’t know the answer, but if I were you I’d stick it out and wait for the 3M. It opens up a lot more opportunities than Mate OSV would.


Unless you are worried about losing your motivation, why not do both?

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Requirements for 3rd mate:

Requirements for Mate OSV:

Exam Guide:

Exams are different. @New3M has good advise.

The less tests, the better. Can’t go wrong avoiding a trade restriction either. Stick it out for the 3rd mate. No sense in pidgeon-holing yourself to just OSVs…

Unless you are in such a hurry and are motivated to take two sets of exams…


As a rule of thumb: Get all you can as fast as you can.

It’s similar, but not the same. There is another exam required to go to 3rd Mate. See page 14 of the exam guide, link posted above. The only times you do not have to test is when there is a note for the specific endorsement you are applying for that says that if you hold X, no exam is required. There is no note excluding the holder of Mate OSV from testing for 3rd Mate. See also 46 CFR 11.903(a) and (c).