Never heard of a two year sea rotation, what happened?
Lol, then you've just shown how limited your knowledge of the USN and the USNR and the enlistment alternatives of the past is. It was a USNR enlistment for six years total with two years active, very common in the 1960s and 1970s, and maybe after that,and pre-DA/DT. There, you learned something.