Who won the final battle and why?

Fig.35. A view of the Floating Batteries exploding, 1782.

Spies kept Eliott informed of everything that was going on; he even knew the date of the attack. When nothing happened, Eliott decided to test his new red-hot shot on one of the batteries recently built on the isthmus. On the 8th September he opened fire and in only two hours, his red-hot shot had
destroyed eight guns and killed or wounded around 300 gunners who were desperately trying to put out the fires.
The destruction of his newest battery forced De Crillon’s hand. He had to start his ‘Grand Attack’ before he lost more batteries to British fire or worse still, the expected British relieving fleet, under Admiral Howe, arrived from England to help in Gibraltar’s defence.
The very next day, the 9th September, all 170 cannons and mortars on the isthmus opened up against the defensive walls between North and King’s Bastion. However, most of their shells were landing behind the Line Wall Batteries. French and Spanish ships in the bay sailed parallel to Line Wall firing broadsides at the fortifications but caused little damage. The next day, the same tactics were repeated and Eliott ordered red-hot shot to be fired against the ships which quickly withdrew rather than face the risk of fire. One ship, however, was badly damaged.

Two days later the combined fleets of France and Spain, consisting of more than 100 ships, sailed into the bay together with the 10 floating batteries. 300 landing craft were also seen being assembled on the Spanish beaches. At Yorktown, such a sight had been enough to encourage the British to surrender, but this was the last thing on Eliott’s mind, and instead he gave orders for an all out defence.
The next day, the 13th September 1783, the ‘Grand Attack’ began when the French and Spanish allies launched their planned attack in an attempt to finally and conclusively end the four year siege. Attacking Gibraltar were, 5190 fighting men, both French and Spanish, aboard 10 of the newly engineered ‘floating batteries’ with 138 heavy guns. There were also 18 ships of the line, 40 Spanish gunboats and 20 bomb- vessels,lk with a total of 30,000 sailors and marines. They were supported by 86 land guns and 35,000 Spanish and French troops (7,000 - 8,000 French) on land, intending to assault the fortifications once they had been demolished. Contemporary accounts tell of an ‘army’ of over 80,000 spectators gathered in the hills over the Spanish border, among them the highest families in the land, assembled to see the fortress defeated.

Fig. 37. The Siege and Relief of Gibraltar, 13 September 1782 by J Singleton Copley. Tate London, 2015.

Details of guards mounted on 7th September 1782 showed an availability of about 10,000 men in the Garrison.
British furnaces were lit up early but the red-hot shot would not be ready until about midday. In the meantime the Spanish and French forces sailed into position off King’s and Montagu Bastions as their aim was to thin out the defending forces and create a breach close to Montagu Bastion to provide rapid access into Casemates. Soon after 10 a.m. the battle began. More than 400 cannon from both sides opened up. At first, British fire failed to penetrate the thick hulls of the floating batteries and, for a while D’Arcon’s invention appeared to really be indestructible.
However, appearances were misleading. By nightfall, smoke began to be seen as hot shot buried themselves deep into the timbers of the hulks. By midnight, the floating batteries at last began to burst into flames. British gunboats left the port in order to harass the Spaniards as they tried to escape but,
seeing the distress of the trapped sailors aboard the burning ships, they began to rescue them (see (Fig. 37). 357 sailors were rescued in this way. Besides officers and men captured by the British, the Spanish and French lost 1,473, drowned, killed, wounded or missing. In contrast British losses were again remarkably light (15 killed and 68 wounded).
Gibraltar could not be taken by force, neither by land nor by sea. It became known as the impregnable fortress and the idiom as ‘strong as the Rock of Gibraltar’ is derived from this time. The cap-badge of the Royal Gibraltar Regiment includes the latin motto ‘Nulli Expugnabilis Hosti’ – which means ‘No enemy shall expel us’ – after the successful defence of Gibraltar against a vastly superior enemy force during the siege.

Fig.38 Destruction of the Floating Batteries at Gibraltar, 14 September 1782.Thomas Whitcombe. National Maritime Museum, Greenwich, London.