Abstract: The cooling device for a power source for a ship propulsion device that pumps up cooling water, from which foreign matters with sizes that cause clogging of a cooling water route have been removed, supplies the cooling water to a cooling water passage (30), and discharges the cooling water to outside after cooling a power source (10) includes: a cartridge-type filtration device (40, 73) that is provided at a midpoint of a first water passage (36, 71) in the cooling water route and incorporates a filter (45, 46) for filtrating foreign matters remaining in the cooling water; and a second water passage (38, 72) that is branched from the first water passage and adapted such that a valve member (53) is opened to cause the cooling water to flow in a case in which clogging occurs in the filter.

Abstract: A built-in propulsion system includes an engine, a diversion unit with a diversion base and an exhaust pipe, and a propulsion unit. The diversion base is connected to the engine, having a water inlet, a water outlet, a diversion channel in communication between the water inlet and the water outlet, a shaft hole above the water inlet and an exhaust chamber behind the shaft hole. The exhaust pipe is fixed on the outer periphery surface of the diversion base in communication with the exhaust chamber. The propulsion unit includes a transmission shaft inserted through the shaft hole and connected to the engine, and an impeller located in the diversion channel and connected to the transmission shaft. The exhaust pipe is used to exhaust the exhaust gas of the engine to the outside of the diversion base to avoid the interference of the exhaust gas and the water flow.

Abstract: A water intake system for a boat spray gun, including a system utilizing a port through a transom of a boat, the port positioned proximate to the bottom portion of the boat; a spray gun system; and a water intake system, comprising: a first water inlet tube having a proximal end connectable to a pump of the spray gun system and a distal end connectable to a swivel; a second water inlet tube having a proximal end and a distal end, the proximal end connectable to the swivel; a port connector connectable to the distal end of the second water inlet tube, the port connector having external threads threadingly engaging the port of the boat; and a water inlet conduit having a proximal end engageable with the port connector and a distal end positioned under the bottom portion of the boat.

Abstract: A watercraft propulsion system includes a motor mounted in a container in a water-tight manner. A shaft extends from the motor through the bottom of the container to an impeller disposed in a housing outside the container. The impeller draws fluid into the housing through and opening on the back of the housing to propel a watercraft through the water.

Abstract: A vehicle for use on the water that can be propelled into the air above the water is provided. The vehicle can include a main body, a board provided on the bottom of the main body, a seat, an inlet for receiving a pressurized incoming water stream, a main nozzle positioned to direct a flow of water beneath the board, handlebars having handle conduits, each handle conduit ending in a nozzle for discharging a flow of water out of the handle conduit and rotatable relative to the vehicle, and conduits supported by the main body, the conduits connected to the inlet and positioned to route a first portion of the incoming water stream to the main nozzle and a second portion of the incoming water stream to the handlebars. The water stream can be supplied to the vehicle from an outlet on a personal water craft.

Abstract: A Motorized Water Vehicle (MWV) adapted to operate as a fluid-compression station in addition to the primary transport function thereof. Such an MWV can supply compressed fluid to a third device. In a preferred and non-exhaustive manner, such an MWV can supply a passenger propulsion device allowing the propulsion device to move through the air or through a fluid. A propulsion system is thereby provided, in which a remote station is a motorized water vehicle adapted to engage with a propulsion device.

Abstract: A thrust generating apparatus which is positioned under water and configured to generate a thrust by ejecting water includes a duct-shaped stator provided with a plurality of armature coils, and a plurality of ring-shaped rotors which are arranged radially inward of the stator and provided with permanent magnets respectively corresponding to the plurality of armature coils, wherein the plurality of rotors are arranged in series in a rotational axis direction thereof and each of the rotors has a propeller vane protruding radially inward. A thrust generating apparatus is capable of outputting a high driving power without increasing a propeller diameter.

Abstract: The invention relates to a Motorized Water Vehicle (MWV) adapted so as to operate as a fluid-compression station in addition to the primary transport function thereof. Such an MWV can thus supply compressed fluid to a third device. In a preferred and non-exhaustive manner, such an MWV can supply a passenger propulsion device allowing the latter to move through the air or through a fluid. The invention thus preferably relates to a propulsion system in which a remote station is a motorized water vehicle adapted such as to engage with a propulsion device.

Abstract: A propulsion system is provided that includes one or more pumps that form a jet for propulsion. A number of Coanda jet devices (CJDs) are coupled to the one or more pumps. The CJDs are arranged so to allow for a multi-axis underwater control of an underwater robot.

Abstract: Jet-powered water craft have become popular recreational pleasure craft for people worldwide as well as providing rapid response in a water environment for life savers, police, customs, etc. However, once the throttle has been cut there is no braking or steering mechanism for such craft. Equally such braking or steering is limited at low speeds. Accordingly it would be beneficial to provide means for braking and/or steering such jet-powered water craft under low speed operation and/or when the throttle is cut. According to embodiments of the invention such mechanisms are provided whilst providing for ease of use during operation as well as beaching/launching/storage.

Abstract: A water jet propulsion device 10 for a water vehicle, such as a boat, is disclosed. The propulsion device 10 comprises a main duct 12 having a main inlet 14 that is arranged to be submerged in use and a main outlet 16, an impeller 30 disposed within the main duct 12 between the main inlet 14 and the main outlet 16, and at least one auxiliary duct 24 having an auxiliary inlet 26 that is arranged to be submerged in use and an auxiliary outlet 28 that opens into the main duct 12 upstream of the impeller 30.

Abstract: A water jet propulsion watercraft includes a hull, an engine disposed inside the hull, a jet propulsion device arranged to be driven by a driving force of the engine, a water detection unit arranged to detect whether or not the hull is immersed in water, and a control unit arranged to restrict an engine rotational speed. The jet propulsion device is arranged to jet water rearward from a jet port to thereby apply a propulsive force to the hull. The water detection unit includes a water detection chamber arranged such that water around the hull is introduced when the hull is in water, and a water level sensor arranged to detect a water level inside the water detection chamber.

Abstract: A watercraft has a hull, a deck, an engine, a steering assembly, a jet pump, a venturi, a steering nozzle, and a reverse gate pivotable between a fully stowed position and a fully lowered position. The reverse gate includes a reverse gate body having inner and outer arcuate surfaces, and reverse gate upper and lower edges. First and second side walls are connected to the sides of the reverse gate body. At least one deflector is connected to at least one of the outer arcuate surface, the first side wall, and the second side wall. The at least one deflector is spaced from the outer arcuate surface. A deflector trailing edge is disposed upwardly and rearwardly from a deflector leading edge at least when the reverse gate is in the fully lowered position. Water deflecting surfaces and turning deflectors connected to a reverse gate are also disclosed.

Abstract: A pump or turbine is disclosed which includes a housing provided with at least one chamber, a rotor, which is rotatably mounted on a shaft in the chamber, an inlet, which communicates with the chamber at least at the location of the shaft, and an outlet channel, which communicates with the chamber at least at the periphery of the rotor. The pump or turbine moreover comprises at least one bypass channel, a first end of which opens into the outlet channel of the pump and a second end of which forms an inlet. The bypass channel may be used for increasing the propelling force or for pumping slurries, for example.

Abstract: An underwater water cannon defense system includes an underwater vehicle, a water cannon coupled to the vehicle, one or more nozzles mounted on the vehicle and directed away therefrom, and water distribution valving mounted in the vehicle that distributes pressurized water to the water cannon and the one or more nozzles in a controlled fashion.

Abstract: A body of water is aerated by propelling in the body of water a water pumping arrangement including a sheath having a turning propeller that (a) sucks water from the body into the sheath interior via openings in the sheath, (b) forces the sucked water upwardly and (c) forces the upwardly forced water through another opening in the sheath below the surface of the body of the water. Water forced through the another opening (i) has speed greater than the speed of the water sucked into the sheath and (ii) causes air bubbles to be induced in the water above the another opening.

Abstract: A seal pressure vent system for a waterjet propulsion apparatus including a water intake section and a pumping unit. The pumping unit is designed such that in operation the seal pressure vent system provides a fluidic path for the flow of high pressure water away from a lip seal assembly toward a near ambient pressure region. The seal vent system includes a plurality of fluid passageways formed in a stator structure in conjunction with a water barrier ring, a tail cone including an extended flange, or a modified stator web structure.

Abstract: The present invention provides a water pump in addition to the impeller system of a marine propulsion system. This allows the water pump to operate independently of the impeller if a clutch is provided which disconnects the impeller from torque transmitting relation with an engine. When a clutch is not provided, the independent water pump of the present invention allows the marine propulsion system to be operated at a lower idle speed than would otherwise be possible because the impeller is not relied upon for a flow of cooling water to the engine.

Abstract: Disclosed is a jet-propulsion watercraft having a simple structure for drawing water as cooling water, the inside of which may be cleaned easily. The watercraft typically comprises an engine, a water jet pump driven by the engine, a two-part pump casing, at least one water drawing passage provided so as to communicate with an inside of the water jet pump in a portion where the two parts of the pump casing are connected to each other, and a component cooled by cooling water taken through the water drawing passage.

Abstract: A water jet propulsion type outboard motor which includes: a power source; a driving system; a housing; a curved tubular duct member; guide blades; and an impeller. The duct member is fixed to the housing on which the power source is mounted, and having a suction port and a discharge port. The guide blades are provided within the duct member in the vicinity of the discharge port of the duct member. The impeller is rotated by the driving system for transmitting a driving power of the power source, and has a spiral blade with outer peripheral edge thereof close to an inner peripheral face of the duct member, and outer peripheral distal end portion thereof extending toward the suction port.

Abstract: Disclosed is a personal watercraft having a water cooling system of an engine, which allows inside of a cooling water passage of an engine or a water passage connected to the cooling water passage to be sufficiently cleaned and a clogged water-supply hole in an expansion chamber to be easily inspected or cleaned. The personal watercraft 1 comprises a first water passage 50 from a water jet pump 7 to a cooling water passage of an engine 4. Water is forcibly sent by the water jet pump 7 and led to the cooling water passage through the first water passage 50. The water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the watercraft. The personal watercraft 1 further comprises a second water passage 53 opened in a surface of a body of the watercraft and communicating with the first water passage 50, and an opening/closing means 54 for opening/closing the second water passage 53.

Abstract: To provide a supercharger cooling structure for a small watercraft which can sufficiently cool the supercharger. In a small watercraft in which an engine with a supercharger is incorporated, cooling water from a jet pump is supplied to the supercharger through a different supercharger cooling water passage independent of any other cooling water passage. The cooling water from the supercharger cooling water passage is first supplied to the supercharger to cool the supercharger and then supplied to an exhaust system provided on the downstream with respect to the supercharger in an exhaust system for the engine, whereafter it is discharged to the outside of the watercraft together with exhaust gas. Oil is supplied to the supercharger for lubrication of a bearing portion of the supercharger and is supplied to an oil jacket formed in a bearing casing to cool the bearing casing.

Abstract: To provide a cooling system for a jet propulsion boat in which the quantity of washing water consumed can be reduced and the appearance is improved. The cooling system for a jet propulsion boat forces the engine to be cooled and forces the exhaust system to be cooled by taking a part of a jet of water emitted from the jet pump (shown in FIG. 1) into the intake path as cooling water and diverging the cooling water taken into the intake path at the diverging duct in a one-way valve unit to flow into the engine-cooling flow path and the exhaust-system-cooling flow path. The cooling system for a jet propulsion boat is provided with a one-way valve at the midsection of the intake path for enabling cooling water to flow from the intake path to the diverging duct and preventing washing water from flowing from the diverging duct towards the intake path.

Abstract: Disclosed is a jet-propulsion watercraft having a simple structure for drawing water as cooling water, the inside of which may be cleaned easily. The watercraft typically comprises an engine, a water jet pump driven by the engine, a two-part pump casing, at least one water drawing passage provided so as to communicate with an inside of the water jet pump in a portion where the two parts of the pump casing are connected to each other, and a component cooled by cooling water taken through the water drawing passage.

Abstract: Disclosed is a personal watercraft having a water cooling system of an engine, which allows inside of a cooling water passage of an engine or a water passage connected to the cooling water passage to be sufficiently cleaned and a clogged water-supply hole in an expansion chamber to be easily inspected or cleaned. The personal watercraft 1 comprises a first water passage 50 from a water jet pump 7 to a cooling water passage of an engine 4. Water is forcibly sent by the water jet pump 7 and led to the cooling water passage through the first water passage 50. The water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the watercraft. The personal watercraft 1 further comprises a second water passage 53 opened in a surface of a body of the watercraft and communicating with the first water passage 50, and an opening/closing means 54 for opening/closing the second water passage 53.

Abstract: A universally adaptable valve, hose and nozzle assembly for use with a personal watercraft. The watercraft includes an interiorly configured engine compartment operated by a throttle, a rear transom forming a portion of the watercraft's structure, a rearwardly extending tail pipe and a bilge line associated with the tail pipe. Elements of the assembly include a bilge pump valve adapted to communicate the interiorly configured engine compartment with the rearwardly extending tail pipe and via the associated bilge line. A water flow diversion member has a first end and a second end, a flexible boot adaptor engaging the first end with the extending end of the tail pipe, a second end of the diversion member extending in communicable and arcuate fashion from the first end.

Abstract: A universally adaptable valve, hose and nozzle assembly for use with a personal watercraft. The watercraft includes an interiorly configured engine compartment operated by a throttle, a rear transom forming a portion of the watercraft's structure, a rearwardly extending tail pipe and a bilge line associated with the tail pipe. Elements of the assembly include a bilge pump valve adapted to communicate the interiorly configured engine compartment with the rearwardly extending tail pipe and via the associated bilge line. A water flow diversion member has a first end and a second end, a flexible boot adaptor engaging the first end with the extending end of the tail pipe, a second end of the diversion member extending in communicable and arcuate fashion from the first end.

Abstract: To provide a speed detecting device mounting structure for a vessel in which a paddle is prevented from being entangled with rubbish and seaweed in the sea, and the paddle is prevented from being damaged or picking-up mud or the like from the sea bottom. In a vessel, a water jet pump is provided at a rear portion thereof. A ship bottom plate is provided below the water jet pump. A speed detecting device is mounted on the ship bottom plate. A paddle of the speed detecting device detects the flow rate of water flow and obtains the propelling speed of the vessel. The speed detecting device mounting structure for a vessel is constructed in such a manner that the paddle of the speed detecting device is disposed on the upper surface of the ship bottom plate, an opening is formed at the portion of the ship bottom plate forwardly of the speed detecting device, and water taken through the opening is guided to the speed detecting device.

Abstract: To provide a supercharger cooling structure for a small watercraft which can sufficiently cool the supercharger. In a small watercraft in which an engine with a supercharger is incorporated, cooling water from a jet pump is supplied to the supercharger through a different supercharger cooling water passage independent of any other cooling water passage. The cooling water from the supercharger cooling water passage is first supplied to the supercharger to cool the supercharger and then supplied to an exhaust system provided on the downstream with respect to the supercharger in an exhaust system for the engine, whereafter it is discharged to the outside of the watercraft together with exhaust gas. Oil is supplied to the supercharger for lubrication of a bearing portion of the supercharger and is supplied to an oil jacket formed in a bearing casing to cool the bearing casing.

Abstract: The invention features a device for generating a plume of water, the device including a) a first side wall, b) a second side wall extending at an angle to the first side wall, the first side wall and the second side wall defining a tapered channel, the channel including i) a first end, ii) a second end, and iii) a longitudinal extent extending between the first end and the second end, c) a first flange extending at an angle to the first side wall, and d) a second flange extending at an angle to the second side wall.

Abstract: A jet powered boat may be provided with a water monitor for fire fighting purposes. The conduit for the monitor is connected to an opening through the bottom of the hull to draw water vertically from beneath the hull. Two motors are provided in the boat. One motor is configured to propel water through the monitor conduit to the water monitor. The other motor is configured to propel water through a propulsion jet at the rear of the boat. In one embodiment, a second propulsion jet is provided at the rear of the boat, connected to the conduit for the water monitor. A baffle at the intersection of the second propulsion jet and the monitor conduit may be operated to selectively direct water to either the monitor or the propulsion jet. In this embodiment, the two motors may be placed symmetrically on either side of the longitudinal centerline of the boat.

Abstract: A detachable firefighting attachment is provided for a personal watercraft having a discharge nozzle. The attachment includes a tubular body having a lower end and upper end. There is a firefighting nozzle mounted on the upper end of the body. A fitting at the lower end of the body is shaped to fit the discharge nozzle of the personal watercraft. Water discharged from the discharge nozzle passes through the conduit to the firefighting nozzle. A forward mount is connected to the body and includes a first component releasibly connectable to the personal watercraft. There may be a steering nozzle communicating with the body adjacent to the fitting. There may be a diverter within the body adjacent to the steering nozzle for diverting water from the personal watercraft through the steering nozzle.

Abstract: A jet powered boat may be provided with a water monitor for fire fighting purposes. The conduit for the monitor is connected to an opening through the bottom of the hull to draw water vertically from beneath the hull. Two motors are provided in the boat. One motor is configured to propel water through the monitor conduit to the water monitor. The other motor is configured to propel water through a propulsion jet at the rear of the boat. In one embodiment, a second propulsion jet is provided at the rear of the boat, connected to the conduit for the water monitor. A baffle at the intersection of the second propulsion jet and the monitor conduit may be operated to selectively direct water to either the monitor or the propulsion jet. In this embodiment, the two motors may be placed symmetrically on either side of the longitudinal centerline of the boat.

Abstract: A water diverting apparatus for adaptation to a recreational motor ski vehicle. The apparatus provides a water rooster tail during the operation of the motor ski vehicle without degrading the nominal speed of the motor ski vehicle or preventing agile maneuvering of the motor ski vehicle.

Abstract: In a ship having water-ejection for driving the ship and spraying water, the water-ejection for the spraying of the water is improved by spraying the water as a fog of droplets, whereby to cool the ship and protect the ship from radioactive fallout.

Abstract: A fire fighting accessory for diverting the water flow generated by a jet propulsion system from the drive unit to a fire fighting implement, the accessory specifically designed to be attached to an existing drive system in a noninterfering relationship with the steering nozzle of the jet. The accessory may be mounted either downstream or upstream of the jet outlet and is controllable from within the vessel. In one embodiment, the accessory coupler is moved into and out of engagement with the drive unit. In an alternative embodiment, a valve system is used to direct water into either the jet outlet or the accessory coupler.

Abstract: A water jet propulsion unit in which water is drawn off of the jet propulsion unit through a tap for other purposes, such as pumping the bilge with a jet pump or delivering coolant to the engine. A filter element which can be easily serviced is positioned in the conduit for precluding small particles which could clog the conduit from entering the conduit.

Abstract: An auxiliary water projector system for use on jet propelled watercraft that only requires removal of the steering nozzle to be connected to the waterjet propulsion system. A thrust control valve is positioned adjacent the remounted steering nozzle. Using the thrust control valve and a flow control valve the operation of the watercraft and auxiliary water projector can be simultaneously controlled to include stationary, forward or reverse movement of the watercraft.

Abstract: A multi-purpose environmental work vessel, to be used in a variety of waterways, canals, and other coastal areas to perform a variety of necessary tasks including skimming oil or debris from the surface of the water, dredging for debris beneath the water's surface, and assisting in firefighting. The vessel includes a catamaran-type hull having a pivotally positioned trash scoop at a forward end of the hull to scoop debris and unload into an adjacently positioned active trash container, a removably positioned dredging system, a fire monitor, a spinning drum-type oil skimmer, an inboard crane, and a pair of outboard motors to propel the vessel and allow it to run at high speeds at a substantially shallow draft.

Abstract: Several embodiments of signalling devices for small jet propelled watercraft that generate an upwardly discharged water spray for indicating the presence of the watercraft. In each embodiment, devices are incorporated for precluding the discharge of the signal spray if desired. In some embodiments, this is done by a control valve while in other embodiments this is done by redirecting the discharge portion of the signal generating device. In all embodiments, however, the signalling device is permanently fixed within the discharge nozzle of the jet propulsion unit.

Abstract: A V bottom hull watercraft powered by a pair of jet propulsion units that are supported for pivotal movement about horizontally disposed pivot axes and rotary movement about a longitudinal pivot axis to rotate the water inlet openings and elevate them from a downwardly facing normal operating position and an upwardly facing service position. The water inlet openings are disposed so that they extend parallel to the sides of the V bottom. Steering nozzles are supported for pivotal movement at the discharge ends of the jet propulsion units and pivot about vertically extending axes that are not perpendicular to the water inlet openings so that no vertical thrust will be exerted on the watercraft hull when the steering nozzles are pivoted to effect steering.

Abstract: A small watercraft having a jet propulsion unit with a flow directing device for creating a rooster tail spray and a reverse thrust bucket that is formed with clearances so as not to interfere with the spray when operating in the forward direction and to permit the reverse thrust bucket to move to its reverse position without interference from the flow directing device.

Abstract: A self propelled floatable nozzle 10 is provided including a support housing 14. A water piping system 16 and an air piping system 18 are supported in the housing 14. The water piping system 16 and air piping system 18 cooperate upon opening and closing of gate valves 32 to provide water for fighting a fire as well as propulsion to move the nozzle 10 in a desired direction as water and air are displaced through orifices 46 and bypass valve 48.

Abstract: A barge has a submersible pump which pumps sea water from a depth of about three feet, heats the water, and uses a boom to direct the heated sea water on the rocks and sand on the beach. The oil which is washed from the beach enters the sea around the barge but is contained by a containment boom. The floating oil in the water around the barge is then recovered by conventional skimming techniques. The sea water from the pump is heated by oil-fired burners. The temperature of the water may be controlled by regulating the amount of heating oil fed to the burners or by varying the number of oil-fired heaters used. The boom is a 100 foot long articulated structure which can be moved across the beach at will to direct the hot water on any desired part of the beach. Either a series of nozzles producing high intensity fan sprays on a series of nozzles producing cone sprays may be selected.

Abstract: A number of embodiments of the invention wherein bilge water is discharged by means of a venturi pump and the discharge is upwardly directed externally of the watercraft to provide a spray that will indicate the watercraft location.

Abstract: A device for protecting a propeller of a boat motor and for improving the efficiency and therefore the performance characteristics of the motor. The device includes a tubular shroud main body portion which includes a pair of half-sections pivotally secured to one another about a first pair of lower, axially aligned edges. Fastening devices are provided along a second pair of upper, axially aligned edges for clamping the half-sections about the propeller. Mounting plate assemblies are mounted on the main body portion half-sections adjacent the upper, axially aligned edges for resiliently gripping a pair of anti-cavitation plates projecting horizontally outwardly from the motor housing. The shroud main body portion is also provided with an elongated slot along the first pair of axially aligned edges for receiving a skeg projecting downwardly from the housing below the propeller. Forward and rearward grills are provided to prevent inflow of trash or other debris into the shroud.

Abstract: A method and apparatus for generating a high plume or "rooster tail" of water behind a water jet propelled marine craft, such as a jet ski, is characterized by the insertion of a water diverting member into the upper regions of the jet of water discharging from the jet propulsion system and diverting a portion of the water from the jet upwardly and outwardly away from the jet to form a tall plume of water above and behind the jet. In its preferred embodiment, the apparatus comprises a lever pivotally mounted on the upper side of the discharge nozzle of the propulsion system and selectively movable at its upstream end through a slot in the nozzle into the interior of the nozzle to divert a portion of the water from the jet stream upwardly and rearwardly away from the nozzle.

Abstract: A number of embodiments for removing bilge water from a jet powered watercraft without obstructing the flow through the jet propulsion unit. In all of the embodiments, a portion of the water pressurized by the jet propulsion unit is diverted through a venturi section and the reduced pressure at the throat of the venturi section is used for drawing the bilge water. In many of the embodiments, the bilge water discharge opening is located so that bubbles will appear to the operator when the watercraft is in an idling mode for indicating to the operator that the bilge has been cleared of water. In one embodiment, the bilge water is discharge into the exhaust system of the engine for aiding in exhaust cooling.

Abstract: This invention is a hydraulic auxiliary power system for a sailboat, and includes a sea-water-driven turbine pulling water from ahead of the hull and forcing it behind the rear of the hull; the turbine being powered by solar energy.

Abstract: This invention is a nozzle system for use on a water craft and in particular a water craft such as a jet ski. A jet ski is a small engine powered surface water craft, usually designed for one person usage, and generally having a small aft deck suitable for standing on by the user. Heretofore, nozzles used on jet skis were pivotally mounted and were used solely to propel or to propel and steer the craft in the water. This invention is for a modified nozzle that additionally produces a small but substantial secondary jet of water directed upwards that breaks through the surface of the water behind the craft and produces a "rooster tail" effect which adds to the safety, excitement and pleasure of the user and produces a spectacular water display that is enjoyed by those observing the craft and its user in action.