500GRT or OSV route?

Hi there.

I’m looking at upgrading to either the 500GRT or Mate OSV.

  1. Are there pros for either one on top of the other in order to get on the bigger boats faster ? I’m not looking at moving away from OSVs as far as I can tell.

  2. looking at the testing requirements from the NMC, is there any major difference between the two routes as far as testing goes?

  3. If I currently hold an OICNW less than 500GT, will that allow me to bypass any of the dozen or so courses now required for the higher tonnage STCW endorsements?

I hope I have worded these questions correctly. Thanks for any and all feedback.

  1. the non OSV restricted license will allow you to work elsewhere in the next downturn, the OSV license covers any tonnage of OSV. I would recommend getting both.

  2. I think the testing is the same.

  3. no.

Also, if you want to pursue working on towing vessels, it will be much easier to cross over from Mate/Master 500/1600 GRT. If you hold Mate OSV, you would need to add a new national endorsement (license). With Mate/Master 500 GRT, you only need the TOAR and at least 30 days on a towing vessel.

But, with Mate 1600 GRT, you would be limited to OSVs of less than 3,000 GT/1600 GRT. Mate OSV is valid for any sized OSV. Also, with Master OSV, there is no exam to go from Master OSV less than 1600 GRT/3000 GT to Master OSV less than 10,000 GT/GRT.

Some of the STCW training for less than 500 GT will meet requirements for 500 GT to 3,000 GT. Most of it won’t. It may depend on the specific approvals that were given to the courses. Check the approvals and the CFR citations in it and see if it would also include the higher tonnage endorsements. Note also that for STCW, there are also different requirements for an endorsement as Master 500 GT to Less Than 3,000 GT than for Master 3,000 GT or More, even for OSVs. So you would likely need additional STCW requirements to work on an OSV of 3,000 GT or More. Again. some of the training and assessments you might have done previously would count for the tonnage increase, others won’t.

The examinations for Mate 500 and Mate OSV are similar, but not identical. The differences are not such that you can say one is easier than the other. But there are differences. See 46 CFR 11.910. I would not factor exams into your decision, other than as noted above to increase the tonnage of Master OSV.

If your immediate goal is to work on an OSV, but want to maximize your options, 3rd Mate Unlimited may be a better option than Mate 500/1600 GRT or Mate OSV. The service requirements will differ, but the examinations will be similar to Mate 500/1600 and Mate OSV.


Thank you for the information. I’m overall undecided with the route to take given the new requirements for STCW. I missed out on the grandfathering that took place a couple years back so I’m playing catch up now.