Sea Year Gyms

There may be equipment on some ships but it likely will vary from ship to ship. There is also a guide to sea year physical fitness at Sea Year Health.
Most ships have a gym. Some good some not so good. You can always take a run on deck and do pushups and situps in your room.
Varies a lot by ship. Keep in mind that you will be working a full time job with few or no days off plus having a ton of sea year projects to work on. It is tough to find time for a regular workout routine.
The Gyms on Tankers are pretty nice but you work 12 hour days 7 days a week. $$$. In fact accomodations on tankers are pretty awesome. As a cadet I had a stateroom with a full dayroom couch, desk area wardrobe closet and drawer and private bath. It was way better than my room as a LT in the Navy aboard a destroyer which I shared with 1 or 2 other officers, 3 bunks high with 3 foldout desks and 1 sink.
You can always try and get on a Prepo ship at Diego Garcia. That is where a lot of football players tend to go in order to maximize their gym time.
I was wondering what kind of equipment do midshipmen have access to during sea year. Thanks!
As everyone else was saying, equipment is carried depending on the ships. MSC ships tend to have good gyms, as many captains were former military. My MSC ship - for first sailing - had a loaded gym. I got lucky with my second sailing ship having a very nice gym as well, before being banished to a makeshift squat rack at Aft Mooring for my third ship. It all depends. There is time to work out fairly consistently while underway; most cadets use it as a break from projects. Maneuvering is where it gets tricky, but it is possible.
Hopefully you will be working enough to where you don't have to work out. I know that as an engine cadet (and later as a licensed engineer) I did get plenty of exercise. I don't recall having any gyms on the ships that I sailed on during Sea Year, but that was over 40 years ago. I have seen some gyms on ships where I had to ride to carry out surveys, but they were hit and miss. On an ATB that I sailed on for several years, we did purchase a rowing machine and placed it in an available space, but it didn't really get much use.