Trust me - It's coming!! I had a buddy like that up until around his mid 30s. I actually went out on a job with him (Inspector with Viceroy Homes)when we were both in our early 30s and no word of a lie, his lunch was a bucket of KFC, a big bag of Doritos and 2litres of Pepsi. He bragged how he felt great and was 6'4" and about 180 lbs. Almost overnight, he developed all kinds of bizarre ailments ranging from reflux to sleep apnia to COPD (never smoked) and a few others. I saw him just before I was posted out of Ottawa last summer (works for Urbandale now) and he is hovering around 350 lbs, can hardly make it up a flight of stairs and has O2 in his truck and at home. Will this happen to all who live this care-free dieting life style for 20 years-I dare say it could happen to most.
Back on track though, along with providing more access to exercise equipment, ships have started introducing healthier foods day to day. Don't get me wrong, you will still have the occasional wing or nacho night when there is a playoff game but the days of 8 trays of duff coming out at 1630 are done (or at least should be). This is likely for the best. Like someone else said, I don't tend to eat as well at sea (though I don't gorge myself) but with all the running around you are doing believe it or not, though it would not constitute a "work out", it defiantly keeps the juices flowing. For any given 8 hour work day alongside, I am probably 4 times more active in a similar period at sea-That said, I am in a position currently that sees me sailing a desk for much of the day. I do building laps once an hour, walk 6-10 k at lunch time and do some stuff when I get home. A typical day at sea though I will still burn more calories than that and that does not include if I get on a bike or rowing machine!
You've got a lot of answers now and my next suggestion is to wait and see what you can do based on your own work schedule, ship's requirements and operational commitments. Good Luck (...again)
Pat