It has been a few years since tats have been an item of discussion, but at the time of last discussion, about 2007, the word was that the uniform used as a standard was the issue bathing suit. All things have a tendancy to evolve over time so this also may be different now, but you need to find out what the standard is. About the worst thing that will happen if the tat is found offensive is that you will be required to have it removed - and they are serious. BTW, according to Admissions the event that brought this issue to the surface involved two incoming plebes who refused to have their tats removed - when they persisted after some serious discussion of the consequences, their appointments were revoked.
