Vessels of the following types are considered under-age for the period after completion indicated below:

1. (1) Battleships—26 years.
2. (2) Aircraft carriers—20 years.
3. (3) Cruisers—20 years.
4. (4) Submarines—13 years.
5. (5) Other combatant surface vessels—16 years.

(Aug. 10, 1956, ch. 1041, 70A Stat. 449.)