Boarding is when the crew of a ship attempt to capture another by forcing their way onboard. For much of naval history it has been the main way of resolving battles at sea. Ancient war galleys, such as those of the Greeks and Persians were armed with heavy rams to pierce the sides of an opponent, but they also carried soldiers and archers. This was because opportunities to ram were rare, and most sea battles degenerated into masses of ships locked together with soldiers jumping from one vessel to another. In the Roman navy a special ramp was designed, called a corvus, with twin steel spikes mounted in the end. A ship was manoeuvred alongside an opponent and the ramp was dropped onto the enemy’s deck to allow the crew to rush across.
In the medieval period boarding was almost the only way of fighting at sea. As a result, the height of a ship became an important factor, giving the crew the advantage of attacking or firing down onto an opponent’s deck. Warships began to resemble fortifications ashore, with high sides and ‘castles’ built up at each end of the hull. Calling the front part of a ship the forecastle dates from this time. The temptation to build ships that were ever taller, and to pack them with heavily armed troops on the upper deck, when heading into battle, made for some notoriously unstable craft. This was true of Henry VIII’s Mary Rose, which capsized and sank in calm weather while sailing out to meet a French attack.
The arrival of heavy cannon onboard warships began to change the nature of naval warfare. By the end of the 17th century naval gunnery had became the main way of engaging an enemy, and pell-mell sea battles between crowds of vessels trying to board gave way to fleets in long lines, manoeuvring across the sea. Even so, although boarding was now used less frequently, it still remained a legitimate tactic. All warships trained both for boarding and repelling boarders. Going into action they would often rig boarding netting to the sides to provide a barrier to an enemy. They also carried a large arsenal of weapons for close combat, including muskets, pistols, blunderbusses, cutlasses, boarding axes and short pikes. There were even some weapons developed just for this type of warfare, such as the strange four-barrelled ‘duck foot’ pistol. All but the smallest warships carried detachments of marines, who were specialists in this fighting.
In some circumstances boarding was a preferred tactic. Both privateers and pirates wanted to capture a prize with as little damage as possible to the ship or its cargo. It was also the only tactic available during a cutting out attack, which was when a ship was captured by an enemy coming alongside in boats. Even in actions between warships, a protagonist who found themselves in an unequal fire fight with a larger enemy could use a swift, surprise boarding to turn the tables on their opponent. Nelson used this tactic to capture the Spanish 80 gun San Nicolás and 112 gun San Josef using the crew of his much smaller 74 gun Captain, at the Battle of Cape St Vincent. In 1798 the French corvette Bayonnaise used boarding to surprise and defeat the larger Royal Navy frigate Ambuscade 32.
Smooth bore cannon in the age of sail were only really effective at ranges below a thousand yards, and most battles took place at even closer distances than this, which kept boarding in play as a possible tactic. Even when the introduction of rifled guns in the 19th century pushed out the range at which sea battles took place, crews were still trained in boarding. It was used in situations in which firing at an enemy was not an option. The suppression of the Atlantic slave trade in the 19th century, for example, was largely carried out in this way, for fear of harming the slaves being liberated.
A similar rationale was behind one of the last full-scale boarding actions between two ships. In February 1940, the German tanker Altmark was returning to Germany with 299 British merchant sailors on board. They were survivors from ships sunk in the early months of the war by the pocket battleship, Admiral Graf Spee. The Altmark was hiding in a Norwegian fjord, when the Royal Navy destroyer HMS Cossack, came alongside. The crew boarded their opponent, and after some fierce hand-to-hand fighting in which seven died and twelve were wounded, the Altmark was captured intact.