Here's the USS America (CV-66) sunk off the East Coast after only 40 years of service.
Well, actually USS America had been decommissioned after 30 years of service, and been mothballed for the ten years previous to her sinking.
Note that the reason it was decommissioned early was DoD budget cuts - it costs a lot to keep a carrier plus its airgroup operational, even ignoring the required escorts. And America was the most expendable carrier, since it was the only non-nuclear carrier left - fuel oil isn't cheap.
Oh, and note also that it did NOT have diesel engines. Old-fashioned steam turbines on that one...