This was in response to the Spanish Armament, and Impregnable served as flag ship to Rear-Admiral Sir Richard Bickerton from August.

The ship continued in service during the Russian Armament of the following year, with her flag officer having changed to Rear-Admiral Phillips Cosby; at the end of this she was paid off in September.

[2] Impregnable was recommissioned in September 1793 by Captain George Blagdon Westcott to serve as the flag ship of Rear-Admiral Benjamin Caldwell, with the French Revolutionary Wars having begun.

[6] At dawn the crew discovered that she had beaten a mile and a half over the shoals and now lay in mud flats near the entrance to Langstone Harbour.

A small flotilla of vessels from Langstone and Spithead dockyards was put to sea to assist, and successfully removed the crew, the ship's guns and other valuables.