1739
When hostilities commenced between Great Britain and Spain, in 1739, the establishment was again augmented.
1740
In the middle of June, 1740, the Fifteenth, twenty-fourth, twenty-seventh regiments, and the six battalions of marines, were encamped on the Isle of Wight, under the orders of General Lord Cathcart. Towards the end of July, the camp broke up, and the Fifteenth, and twenty-fourth regiments, and the six regiments of marines, embarked on board the fleet for the West Indies. Some delay occurred, and after putting to sea, the fleet was twice driven back by contrary winds; on the 26th of October it sailed a third time, and was dispersed by a tempest in the Bay of Biscay; but the greater part of the vessels were recollected and proceeded on the voyage. Arriving at Dominica to provide wood and water, the troops lost their gallant leader, General Lord Cathcart (then colonel of the sixth dragoon guards or Carabineers), who died of dysentery; and the command devolved on Brigadier-General Thomas Wentworth.
1741
The expedition arrived at Jamaica in January, 1741, and the appearance of this force dispelled the apprehension of an attack on that island by the combined fleets of France and Spain, and also enabled the British commanders to act offensively. The expedition put to sea, and after some delay, an attack on Carthagena, the capital of a wealthy province in the country of Terra Firma, in South America, was resolved upon. This place was found strongly fortified, and the garrison reinforced by the crews of a squadron of large ships; at the same time the season for active service in that part of the world was fast passing away; but the design was persevered in, and the fleet having silenced several small forts, the Fifteenth mustering one thousand officers and soldiers, and several other corps, landed on an island near the mouth of the harbour, on the 10th of March, and commenced the siege of the principal fort, or castle, called Bocca-chica. On the evening of the 25th of March, the grenadiers of the Fifteenth, and other regiments, mounted the breach in gallant style, to storm the fortress, when the Spanish garrison fled, and the place was captured without loss.
Channels having been made through the sunk vessels with which the Spaniards had blocked up the entrance to the harbour, the Fifteenth and twenty-fourth re-embarked, and commenced landing near the city of Carthagena. From the place of landing, the two regiments advanced along a defile, preceded by the grenadiers, through a country covered with trees and herbage of luxuriant growth, the interwoven branches forming a shelter impenetrable both to heat and light, and several men were wounded by shots fired from the tracks and openings into the wood. Diverging from the defile, the two regiments encountered a body of Spaniards advantageously posted to dispute the passage, but as the grenadiers sprang forward to commence the attack, the enemy fled. The two regiments proceeded to the vicinity of the castle of St. Lazar, which commands the town, and were followed by the six battalions of marines. The soldiers passed three nights in the open air, for want of tents and tools, and their health was seriously injured.
The siege of the castle was commenced; and as the men were fast decreasing in numbers from the effects of hard duty and climate, Brigadier-General Wentworth was induced to attack the place by escalade, to which dangerous enterprise he was urged by Vice-Admiral Vernon. Twelve hundred men stormed the enemy's entrenchments under the walls of the fort, exposed to a heavy fire of musketry. The grenadiers, led by Colonel Grant, rushed forward with astonishing bravery, and leaping into the lines, carried the works in gallant style. The Spaniards fled over a drawbridge into the fort. The British pursued, and called for ladders to storm the fort; but the fire was so hot, that the Americans who carried the ladders threw them down and fled. Meanwhile the storming party was exposed to a destructive fire. At length three ladders were brought forward, and a serjeant and ten grenadiers mounted the walls, but were instantly cut to pieces, excepting the serjeant, who saved himself by leaping down again. Several of the ladders were found too short: it was ascertained that, owing to a guide having been killed, the attack had been made on the strongest part of the works; Colonel Grant fell mortally wounded; and after sustaining a most destructive fire for several hours with intrepidity and perseverance, the troops were ordered to retire, having sustained a severe loss in killed and wounded.
Violent periodical rains commenced; the country was deluged with water, and the change of atmosphere produced fatal effects on the health of the men, who were drenched with rain. All hope of further success immediately vanished, and the troops returned on board the fleet, where numbers died from the distempers peculiar to the climate.
The forts of the harbour of Carthagena having been demolished, the fleet sailed to Jamaica. The Fifteenth, and several other corps, afterwards sailed to the island of Cuba, where they landed, and a camp was formed twenty miles up one of the large rivers of the island. At this camp, the regiment was stationed some time; and the country was reconnoitred in various directions by detachments. The design of forming a British settlement on that part of the island of Cuba, was, however, abandoned; in November the troops returned on board ship, and were re-conveyed to Jamaica.