Watercraft The term watercraft covers a range of different vehicles including ships , boats , hovercraft and submarines , and differs from a simple device that merely floats , such as a log raft . Great Ships . Seafaring has a large corpus of traditional lore associated with watercrafts , in both its meanings , as the foundation of its heritage and culture in which most seafarers see a significant degree of pride , and which forms their trade and professional identity . This is often reflected in the industry - specific terminology and concepts that have been retained and are now applied for the sake of tradition alone . Aside from small craft used by individuals , maritime tradition identifies a ship as any water vehicle that has , or is capable of carrying three masts within its hull . Three masted ships at one time were called the " Great Ships " , and marked transition in European seafaring from shallow coastal waters of the " Age of Navigation " confined primarily to the European shores and those of North Africa , via the " Age of Discovery " of other continents in relative proximity of Western Europe , to the " deep sea " oceanic sailing of the " Age of Sail " . The term ' a great ship ' therefore holds a deeper and far more significant meaning to seafarers than ' landlubbers ' , or those who do not serve on ships or other vessels , and has remained so through the " Age of Steam " and into the 21st century . While rigged masts have been discontinued for the vast majority of ships since the late 19th century , a rule of thumb based on the hull having a wooden construction would determine her as a ship . If the length of the watercraft deck prevents the mounting of three masts , it is a boat , while a single - masted hull can be termed a craft . This is paralleled with the degree of difficulty that was required in the past by different trades constructing the hull based on complexity . A ship was always constructed by a shipwright working with a naval surveyor or a naval architect . A boat could be constructed by a ship ' s carpenter . A watercraft such as a lifeboat , a dinghy , or a runabout could be constructed by any craftsman familiar with woodworking , such as a builder ' s carpenter or a joiner , or by a qualified marine trades person or shipwright . Uses of water craft . Usually the purposes behind watercraft designs and skills are for seafaring education or leisure activities , fishing and resource extraction , transportation of cargo or passengers , and for conducting combat or salvage operations . In general , the purpose of a water vehicle identifies its utility with a maritime industry sub - sector . Design . The design from which a water vehicle is created usually seeks to achieve a balance between internal capacity ( tonnage ) , speed and seaworthiness . Tonnage is predominantly a consideration in transport operations , speed is important for warships , and safety is a primary consideration for less experienced or often smaller and less stable training and leisure vehicles . This is due to the great level of regulatory compliance required by the larger watercraft , which ensures very infrequent instances of foundering at sea through application of extensive computer modeling and ship model basin testing before shipyard construction begins . Propulsion . Propulsion is the primary application of technology in watercraft . Historically water vehicles have been propelled by poles , paddles or oar s , through manipulation of sailing rigs that propel by lifting using the wind , and a variety of engineered machinery that creates subsurface thrust through the process or internal combustion . The technological history of watercraft in the European history can be divided into marine propulsion using the simple paddle craft , oared galleys from the 8th century BCE until 15th century , lateen sail during the Age of Discovery from the early 15th century and into the early 17th century , full rigged ship s of the Age of Sail from the 16th to the mid 19th century , the Age of Steam marine steam engine roughly between 1770 and use of the steam turbine until 1914 , the internal combustion engines using diesel , petrol and LNG as fuels from the turn of the 20th century , which has been supplemented to some degree with the nuclear marine propulsion since the 1950s . Current technological development seeks to identify cheaper , renewable and less polluting sources of propulsion for watercraft of all shapes and sizes . Construction . Secondary applications of technology in watercraft have been those of used structural materials , navigation aids , and in the case of warship s , weapon systems . The purpose of usage and the physical environment define the materials used in construction which had historically included grasses , leather , timbers , metals combined with timber or without , silicate and plastic derivatives , and others . Navigation . Navigation aids have varied over time from astronomical observation , to mechanical mechanisms , and more recently analog and digital computer devices that now rely on GPS systems . Weapons . Naval weapon systems have closely followed the development in land weapons , developing from : Until development of steam propulsion was coupled with rapid firing breach - loading guns , naval combat was often concluded by a boarding combat between the opposing crews . Since the early 20th century , there has been a substantial development in technologies which allow force projection from a naval task force to a land objective using marine infantry .