Breast milk will keep in a cooler for at least 8 hours, and usually longer. So I would imagine that you will be fine with the fridges on the ship since, after all, your child will be with you (right?). I didn't have access to a refrigerator at work when I was pumping, just a cooler. 10 hour days, plus commute, and I often pumped first thing when I arrived. Total of more then 2 years of pumping across both kids. Never had milk spoil from that (you can tell when it spoils, it gets stinky). So as long as you are tracking which milk is oldest, and using that first, it should be totally fine. I think the fridges are pretty close to regular fridges, not just coolers.
Also, FYI, kellymom used to be evidence based, but it is not any more -- many articles have not been updated in years, and are now quite outdated. While it is still where I would go first, I would confirm any critical information with another source or with a certified lactation consultant.