subclass_of type 202 submarine
A ___MASK90___ is a large buoyant ___MASK75___ . Ships are generally distinguished from boats based on size , ___MASK39___ and cargo or passenger capacity . Ships are used on lakes , seas , rivers , and oceans for a variety of activities , such as the transport of people or goods , ___MASK86___ , entertainment , public safety , and warfare . Historically , a " ___MASK90___ " was a sailing vessel with at least three square - rigged masts and a full bowsprit . Remotely operated vehicles are vehicles which are controlled by an ___MASK17___ who is not in the ___MASK58___ . These can be operated by radio control , or through a cable or line connecting the ___MASK58___ to the operators location . A ___MASK27___ is a small ___MASK58___ designed to operate underwater . The term " ___MASK27___ " is often used to differentiate from other underwater vehicles known as submarines , in that a submarine is a fully autonomous ___MASK50___ , capable of renewing its own power and breathing air , whereas a ___MASK27___ is usually supported by a surface vessel , platform , shore team or sometimes a larger submarine . In common usage by the general public , however , the word " submarine " may be used to describe a ___MASK50___ that is by the technical definition actually a ___MASK27___ . There are many types of submersibles , including both crewed and uncrewed ___MASK50___ , otherwise known as remotely operated vehicles or ROVs . Submersibles have many uses worldwide , such as oceanography , underwater archaeology , ocean exploration , adventure , equipment maintenance and recovery , and underwater videography . A wet sub is a ___MASK6___ of ___MASK89___ ( submarine ) that does not provide a dry environment for its occupants . Usually , wetsuited scuba divers will ride upon the device ( as one would ride a motorcycle or with an opening as in an Olympic bobsled ), although it can be designed to fully enclose its occupant ( s ) to provide lower drag . An enclosed vehicle may provide a dry viewing chamber for the occupant ( s ). The motive force is an electric motor and usually the power source is an electric battery . The depth and duration at depth is typically limited by the requirements of a scuba diver . A ___MASK61___ ( also called a mini submarine ) is any submarine under 150 tons . Typically operated by a crew of one or two but sometimes up to 6 or 9 , with little or no on - board living accommodation , they normally work with mother ships , from which they are launched and recovered , and which provide living accommodation for the crew and other support staff . A ___MASK55___ is a watercraft of a large range of sizes designed to float , plane , work or travel on ___MASK1___ . Small boats are typically found on inland waterways ( e . g ., rivers and lakes ) or in protected coastal areas . However , boats such as the whaleboat were designed for operation from a ship in an offshore environment . In naval terms , a ___MASK55___ is a vessel small enough to be carried aboard another vessel ( a ship ). Another less restrictive definition is a vessel that can be lifted out of the ___MASK1___ . Some definitions do not make a distinction in size , as bulk freighters long on the Great Lakes are called oreboats . For reasons of naval tradition , submarines are usually referred to as ' boats ' rather than ' ships ', regardless of their size and shape . Ships are generally distinguished from boats based on their larger size , shape and cargo or passenger capacity . A ___MASK34___ is a watercraft capable of independent operation underwater . It differs from a ___MASK27___ , which has more limited underwater capability . The term most commonly refers to a large , crewed vessel . It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots , as well as medium - sized or smaller vessels , such as the ___MASK61___ and the wet sub . Used as an adjective in phrases such as " ___MASK34___ cable ", " ___MASK34___ " means " under the sea ". The noun " ___MASK34___ " evolved as a shortened form of " ___MASK34___ boat " ( and is often further shortened to " sub "). For reasons of naval tradition , submarines are usually referred to as " boats " rather than as " ships ", regardless of their size . The ___MASK6___ 202 was a short lived class of German submarines . Design of these very small submarines started in 1957 by Ingenieurkontor Lübeck ( IKL ) . It was intended to build 40 ___MASK6___ 202 mini submarines with a six man ___MASK74___ but technical difficulties and doubts about their usefulness reduced them to three , and of those three for trials , to be further reduced to two . The boats were in service only a few months and were scrapped shortly after . They were one of the few military U - Boats not bearing `` U - numbers '' , probably since they were never intended for combat use . Instead they were named after important German engineers in ___MASK34___ constructions ( like Wilhelm Bauer ) . Hans Techel was built with traditional propeller and rudders ( similar to the ___MASK6___ 205 submarines ) , but Friedrich Schürer had a rotatable Kort nozzle instead . ___MASK75___ are ___MASK1___ - borne vehicles including ships , boats , hovercraft and submarines . ___MASK75___ usually have propulsive capability ( whether by sail , oar or engine ) and hence are distinct from a simple device that merely floats , such as a log raft .