Razee

In the Royal Navy, the razee operation was typically performed on a smaller two-deck ship of the line, resulting in a large frigate.

The rationale for this apparent reduction in gun power was that the smaller ships-of-the-line could no longer be used safely in fleet actions as the overall size and armament of opposing ships increased.

Towards the close of the Napoleonic Wars, three elderly 74-gun ships were razeed into 58-gun fourth rates (not losing a complete deck, so remaining a two-decker, but having the quarterdeck removed).

Advances in metallurgy and artillery in the 1850s allowed the casting of guns that fired substantially heavier shot than had previously been in use, as well as exploding shells.

Thus, when the decision was made to rearm these frigates with heavier but fewer guns, the reduction in crew size allowed the ships to be razeed.