Another Santísima Trinidad conversion would require a hull survey

Could the Royal Navy remove two decks from a captured Santísima Trinidad after 1805?

Possibly, but the repeatedly altered hull would need forensic inspection and might be too structurally exhausted to justify another major conversion.

The hull had already experienced repeated additions, conversions, and structural stress. Predicting another conversion without a detailed forensic study would be unreliable. Removing two decks might be physically possible, but the more important question is what the accumulated work has done to the timber structure. The likely burden would fall on the shipwrights and carpenters expected to keep an overworked hull serviceable.