Below is a US Navy standard issue enlisted mattress.
(26.5" Wide x 76" Long x 4" Deep
The photos below were taken with the same set of
sheets.  The flexibility of our design ensures a snug
fit on both enlisted and office racks.
(Below: Jr. Officer berth with mattress size of 28" wide, 76" long, & 6" deep)
(Below: Enlisted berth with mattress size of 26.5" wide, 76" long, & 2" deep)