The Revolutionary War with France broke out in 1793, leading to the extensive modernisation of the castle. Repairs were carried out in 1794 at a cost of £647, followed by a review of the defences the next year by the Master-General of the Ordnance. The 16th-century castle was still strongly fortified by the standards of the time, but it could not support the heavier guns or batteries of artillery required to tackle enemy warships. Instead, two new gun batteries, each armed with five 36-pounder (16.3 kg) guns, were built alongside the castle in 1795, with a further eighteen 9-pounder (4 kg) guns mounted in the old fort; the guns concerned had all been captured from the French.