Boarding ( attack ) Boarding , in its simplest sense , refers to the insertion onto a ship ' s deck of personnel . However , when it is classified as an attack , in most contexts , it refers to the forcible insertion of personnel that are not members of the crew by another party without the consent of the captain or crew . Boarding may be carried out during wartime by naval infantry in an attempt to seize and possibly destroy the vessel , or it may occur in peacetime by pirates and other criminals , or as a means of inspection by a nation ' s coast guard ( or navy ) to prevent piracy and smuggling . In wartime . Boarding is used in wartime as a way to seize a vessel without destroying it , or to remove its cargo ( people or goods ) before it is destroyed . It can also be used to aid in the collection of naval intelligence , as soldiers boarding a sinking , crippled , or surrendered vessel could possibly recover enemy plans , cipher codebooks or machines . For a boarding to be successful , it must occur without the knowledge of the crew of the defending ship , or the ship ' s defenses must be suppressed . In modern warfare , boarding by military forces may involve the use of small submersibles , inflatable boat s , or helicopter s to carry troops to the deck of the ship , or may simply be carried out by scuba divers scaling the sides of the ship . In peacetime . In peacetime , boarding allows authorized inspectors of one nation or group , such as a Coast Guard or an international policing fleet ( e . g . United Nations fleet ) to examine a ship ' s cargo in a search for drugs , weapons , passengers which are unrecorded on the ship ' s manifest , or any other type of contraband that could possibly have been carried aboard . A nation ' s Coast Guard could also board any suspicious ships that have been overfishing in such a nation ' s territorial waters . History of boarding . Boarding is one of the oldest methods of securing an opposing ship , as the first cases were depicted when the Sea Peoples and Egyptians fought . For cultures that lack effective shipboard artillery , boarding is the main technique of ship - to - ship combat . However , in the modern era , boarding is still used , particularly when stealth is desired . In all eras , boarding requires that the ship boarded be stable enough to withstand the impact of enemy personnel leaping or climbing onto the deck and a subsequent sustained fight . The target ship must also have enough deck space for boarders to be able to stand and fight effectively . Thus , Native American war canoes or New Zealand Waka s were not suitable boarding targets , and wars between sides equipped with such vessels have generally not seen boarding actions , or any other decisive form of ship - to - ship combat . Instead , such vessels were often used for the rapid transportation of troops and supplies , and decisive engagements were normally fought by landing forces . Boarding in the ancient and medieval world . Throughout the classical and medieval periods , all naval ship - to - ship combat focused primarily on boarding , although ramming and incendiaries were secondary tactics . Greek and Persian naval tactics emphasized ramming and boarding , notably at the Battle of Salamis . The earliest Roman naval battles against Carthage also emphasized boarding . Since the Romans were primarily a land - based army , they could not effectively combat the Carthaginian navy , and subsequently lost several sea battles . The corvus , a boarding ramp with two steel spikes , was the Roman answer to this problem . Roman sailors piloted their ship alongside a Carthaginian ship , dropped the corvus from one deck to the other , and sent their soldiers across the board , assaulting the ship . The Carthaginian navy , unprepared for this " land combat " on the oceans , lost several ships to this tactic . This invention secured Roman naval dominance in the Mediterranean Sea for several centuries . During the medieval period , boarding continued to be the dominant form of ship - to - ship combat . The most prominent naval power of the period , the Vikings , rarely fought other seaborne peoples on the water , but they still depended on boarding on those rare occasions , often lashing their longship s together to make a more stable platform for the upcoming battle . The maritime use of Greek fire made Byzantium less dependent on boarding than other medieval powers , but it was still used . To better resist boarding , medieval European ships began to be built with high wooden " castles " fore and aft , which boarders could scale only with great difficulty , while archers or harquebusiers could sweep the enemy decks . Medieval China , Korea , and Japan were also dependent on boarding tactics , with the flat expanse of a ship used as a battleground for the marine contingents on the ships . The Battle of Dan - no - ura in 1185 was one of the classic naval battles in medieval Asia to be decided by boarding . Boarding attacks occurred also beyond the medieval era in Asia . During the Imjin Wars in naval operations , both Korean and Japanese marines would attempt to board the other ' s ships for engagement in melee combat . The Japanese used boarding attacks more often because of the imbalance of firepower between the two navies ; at the time , the Koreans controlled a much more powerful navy , technically and tactically , than the Japanese . Though the Japanese were armed with the latest in European small firearms , Korean cannons were advanced and among the best in Asia at the time ; therefore , it was very easy for Korean ships , using cannons , to destroy Japanese ships . Boarding in the Age of Sail . The development in the early 16th century of shipboard gunports and gun carriages , and the consequent adoption of broadside tactics , gradually ended the primacy of boarding in naval warfare . The decline in boarding occurred faster in Northern and Western Europe than in the Mediterranean . While England and France quickly designed ships with heavy broadsides , the Mediterranean ' s lighter winds encouraged the Spaniards , Italians and Ottomans to retain the rowed galley , which was difficult to equip with heavy broadsides because the weight and size of the artillery interfered with the oar banks . As late as 1571 , the Mediterranean Battle of Lepanto , while influenced by artillery , was still principally a battle determined by boarding . The defeat of Spain ' s Great Armada in 1588 struck the death knell for major fleets geared toward boarding . The Spanish galleon s were intended primarily for boarding combat , their contingents of boarding soldiers far outnumbering the English and their decks provided with high castles for suppressive fire . But the Armada proved unable to close with the English vessels , partly because the Spanish castles rendered their ships more sluggish , while Drake and Hawkins stood off and bombarded the Spanish from long range , tearing up their rigging and decimating their crews with the superior firepower of their broadsides . This enabled the outnumbered English fleet to avoid being boarded and prevent a Spanish landing . While boarding would never again be the dominant tactic in Western naval warfare , it was not abandoned . Boarding was still used as the coup de grace against a crippled ship , enabling the victimized vessel to be recovered and used by the boarders ' side rather than being sunk . Important information such as enemy plans , ciphers or rutter s might also be recovered . Large quantities of soldiers were consigned to transports rather than " pestering " the decks of warships , but smaller units of specialized marines were kept aboard to aid in boarding ( as well as to enforce naval discipline ) . Sailors themselves were now expected to play the major role in boarding combat . Boarding was of particular importance in the 17th and 18th centuries ' " guerre du course " , or commerce raiding , as well as to privateers and pirates . Because naval crews were paid prize money for bringing back enemy merchant shipping and cargoes intact , it was preferable to capture such ships rather than sink them , which ultimately required boarding , with or without a preliminary artillery duel . Privateers and pirates found boarding even more necessary , as both depended entirely on capturing merchant vessels for their livelihood , under the wageless system of " no purchase , no pay . " There were two chief techniques of boarding in the Age of Sail . One was to bring the two ships close enough to actually step from or leap from one ' s own gunwale to the enemy ' s deck . Grappling hooks and lines assisted in keeping the vessels side by side . The second option was to place a boarding party onto a dory , gig , or another type of small boat , row it alongside the target , and then climb aboard by using grappling hooks or the steps built into some ship ' s sides . The cinematic method of throwing a grappling line into the enemy ' s rigging or yards and then swinging aboard does not appear to have any historical support , as this could hardly have been practical , and brought a soldier within range of a large group of hostile combatants extremely quickly . In addition , it would be hard for large numbers sufficient to overwhelm the other ship ' s defenses to be brought onto the deck in this fashion . Boarding in the Age of Sail was more difficult and dangerous than in previous eras of open - decked sailing vessels . Defenders could seek cover in " closed quarters " in the ship ' s roundhouse or foredeck , shooting through small loopholes at the exposed boarders . The defenders could also place grenade s on their gunwales or dangle them from their yards , detonating them by fuses of quick match that led back through the loopholes into the closed quarters . If not in closed quarters , defenders sometimes resorted to the boarding pike , trying to kill or wound boarders while keeping them at a distance , and of course might use any of the weapons that the boarders themselves used . Boarding weapons in the Age of Sail consisted of grenades , musket s , pistol s , cutlass es , numerous other blades , and the short - barreled shotguns called blunderbuss es . Until the 19th century introduction of the percussion cap , sailors preferred to use flintlock s whenever possible , as the lighted match of a matchlock was extremely dangerous to use on board a ship . Spanish and Portuguese sailors , especially officers , were known to use the rapier throughout the 17th and even into the 18th century , but the close - quarter nature of boarding combat rendered these lengthy swords very ineffective . An important weapon often overlooked by historians was the boarding axe , useful for attacking the enemy , but also essential for chopping down doors and bulkheads to break into closed quarters where the defenders of a ship could barricade themselves . The heavy blade could also cut grappling lines . The continued success throughout the 18th century of boarding tactics in a secondary role is best exemplified by John Paul Jones ' assault against the HMS " Serapis " from the sinking USS " Bonhomme Richard " in 1779 , the only known case in the Age of Sail where a ship ' s captain captured an enemy ship while losing his own . The HMS " Shannon " in turn broke the United States ' run of successful frigate battles during the War of 1812 by boarding and capturing the USS " Chesapeake " in 1813 . The " cutting out expedition , " a boarding attack by small boats , preferably at night and against an unsuspecting and anchored target , became popular throughout the later 18th century and during the Napoleonic wars . This heralded the emphasis on stealth and surprise that would come to dominate future boarding tactics . Modern era . The adoption of ironclads and increasingly powerful naval artillery vastly increased the risk to boarding parties . Meanwhile , the suppression of piracy and the abandonment of privateering and prize money made boarding actions even against merchant vessels less rewarding . The massacre of Paraguayan canoe - borne boarding parties by Brazilian ironclads during the Paraguayan War demonstrated the futility of direct assault by boarding in the face of 19th - century technology . During World War I the Royal Navy created their own type of warship specifically designed for boarding . Several armed boarding steamer s were converted from merchant ships and fought in engagements such as the Action of 16 March 1917 . For the most part , boarding became a police action in which the attackers came on board only when no resistance could be expected , in order to search vessels and remove contraband . The target would be a ship that had hove to or surrendered . During wartime , the surrendering or sinking ship would be searched for any valuable information such as plans and cipher s . One prominent example would be during World War II , when a British vessels crippled the " U - 110 " in 1941 , and sent its crew onboard after the U - boat commander , Kapitänleutnant Fritz - Julius Lemp , gave the order to abandon ship . The British would be rewarded with a fully operational Enigma cipher machine , left behind by the German sailors . On June 4 , 1944 a United States Navy task force led by Captain Daniel V . Gallery boarded and captured the " U - 505 " . True boarding assaults in the 19th , 20th , and 21st centuries became extremely rare , generally by small boats or by divers , who entered the target vessel surreptitiously and exploited total surprise to seize control before resistance could be effectively organized . Modern - day pirates in motorboats similarly depend on speed , stealth and surprise to take their targets , usually unarmed and poorly defended , without serious resistance .