Low profile vent assembly for a boat

A vent assembly in accordance with some examples herein may include a vent conduit coupling a dry compartment of a boat to an opening in a hull of the boat for selectively fluidly connecting the dry compartment to an exterior of the hull. The vent assembly may include a fluid-tight ventilation closure which selectively prevents fluid flow through the vent conduit when the fluid-tight ventilation closure is in a closed position. The fluid-tight ventilation closure may be positioned below an exterior surface of the hull. A damper may be configured to selectively modulate air flow through the vent conduit. The damper may be positioned downstream of the fluid-tight ventilation closure from the opening.

TECHNICAL FIELD

Examples described herein relate generally to a low profile vent assembly and method for fluidly sealing an opening in a hull of a boat while preserving the hull profile of the boat.

BACKGROUND

In enclosed spaces on a boat, such as in enclosed dry compartments of the boat (e.g., the engine compartment, cargo area, or crew compartment), or in enclosed spaces of other vessels or industrial facilities where internal temperature control may be needed, ventilation ducting, fans and ancillary equipment are often installed to facilitate regulation of the internal temperature. A ventilation system may be used to provide air into the enclosed compartment e.g., to operate the machine and/or to cool machinery such as prime movers, electronics, reactors, or other equipment that generates heat. In boats, ventilation may be desired for any internal fluid tight compartment of the boat (also referred to as dry areas or compartments), and such ventilation typically requires the use of one or more vent openings, conventionally provided at the end of structures extending above the deck of the boat so as to avoid or reduce the risk of the vent openings being downflooding points on the vessel. Such conventional solutions, however, may negatively impact the vessel profile that may affect it aesthetically, with regard to safety, or observability.

SUMMARY

Described here are examples of a low profile vent assembly for a boat. The vent assembly includes a vent conduit coupling a dry compartment of a boat to an opening in a hull of the boat for selectively fluidly connecting the dry compartment to an exterior of the hull. A fluid-tight ventilation closure selectively prevents fluid flow through the vent conduit when the fluid-tight ventilation closure is in a closed position. The fluid-tight ventilation closure is positioned below an exterior surface of the hull. A damper is configured to selectively modulate air flow through the vent conduit and is positioned downstream of the fluid-tight ventilation closure from the opening.

The fluid-tight ventilation closure may include a fluid-tight valve configured to selectively allow fluid communication from an internal space defined within a hull of the boat when the valve is in an open position, and to prevent the passage of fluid across the valve (e.g., into the internal space) when the valve is in a closed position. The low profile vent assembly may include a drain configured to dispose of any fluid that has collected into the low profile vent assembly (e.g., within the vent conduit) such as to prevent passage of the fluid into the internal space of the boat.

In some embodiments, the low profile vent assembly may include an air mover configured to move air through the internal space of the boat. In some embodiments, the low profile vent assembly includes a water ingress sensor to detect the ingress of water. Some examples of water ingress sensors include conductivity or float sensors. In some embodiments, the fluid-tight ventilation closure is closed upon a detection of a condition corresponding to a threat of an ingress of water into the internal space of the boat. In some embodiments, the condition is correlated to one of a roll, a pitch, or a yaw of the boat, and may be detected by an accelerometer. In some embodiments, the detection of the condition is correlated to the listing of the boat. In some embodiments, the fluid-tight ventilation closure is a valve that is automatically closed in response to detection of the condition. In some embodiments, the damper is fire-rated and configured to close upon the detection of a fire. In some embodiments, a fire may be detected by a sensor arranged to detect: a temperature of the internal space rising above a threshold, the presence of smoke in the internal space, a time rate of temperature rise, a wavelength of light associated with the fire, or any combinations thereof.

In some embodiments, the low profile vent assembly includes a valve with a flange fixed to a deck of the boat; an aperture defined in the flange that allows the fluid communication from a peripheral inner surface to an outer surface of the deck; a protrusion extending around the peripheral inner surface; a cylinder structure extending inward into the internal space from the peripheral inner surface of the valve below the flange. The cylinder structure may include a passage portion including a plurality of circumferentially spaced apart openings that provide fluid communication between the internal space and the aperture. The valve includes a shaft structure positioned within the cylinder structure and operable to move relative to the cylinder structure and relative to the aperture. The shaft structure includes a retaining groove at a top end of the shaft structure, and a resilient seal disposed in the retaining groove and operable to seal against the protrusion to prevent the ingress of water into the boat. In some embodiments, the shaft structure includes a longitudinal axis about which the shaft structure rotates, and a set of shaft structure threads. The cylinder structure includes a set of cylinder threads that mate with the shaft structure threads such that the cylinder structure guides the shaft structure upward and downward between a sealed and an unsealed configuration of the valve as the shaft structure rotates relative to the cylinder structure.

A method of preventing downflooding of a boat is disclosed. The method includes providing a low profile vent assembly as disclosed herein. The method includes detecting a condition corresponding to a threat of an ingress of water into the dry compartment of the boat. In various embodiments, the condition corresponds to a roll, a pitch, a yaw, or listing of the boat. The method includes generating a control signal in response to the detection of the condition, actuating an actuator in response to the control signal, and closing the fluid-tight ventilation closure of the low profile vent assembly

In some embodiments, the method includes detecting the ingress of water into the internal space of the boat; closing the fluid ventilation closure; and collecting and disposing of the ingressed water.

In some embodiments, the method includes detecting a fire; and closing the damper. In various embodiments, the method includes detecting the fire by detecting a temperature of the internal space rising above a threshold; a presence of smoke in the internal space; a time rate of temperature rise; or a wavelength of light associated with the fire.

DETAILED DESCRIPTION

Described here are examples of low profile vent assemblies which may be used to provide a fluid-tight seal across a vent opening, for example an air intake or outlet of an engine compartment of a boat to reduce the risk of downflooding while preserving a low profile of the boat. A low profile vent assembly may be desirable for aesthetics, safety or observability of a boat. For example, a low profile vent assembly may be included in a boat without affecting the aesthetics, safety or observability of the boat. In some embodiments, the vent assembly includes a vent conduit, which couples a dry compartment of the boat to an opening in the hull of the boat for selectively fluidly connecting the dry compartment to an exterior of the hull. As used herein, “selectively fluidly connecting” refers to an ability of a fluid-tight ventilation closure according to the present disclosure to establish, sever, regulate, or control fluid communication between one portion of a boat and one or more of: the exterior of environment around the boat, and another portion of the boat, and to do so based on an input or command (either electrical or physical) from an external controller, actuator, a sensor, or a person. The low profile vent assembly may include a fluid-tight ventilation closure that prevents fluids from passing into, or out of, the boat. The fluid-tight ventilation closure may include a valve operatively associated with the vent conduit. The valve is operable to selectively prevent the flow of fluids (e.g., water or other liquids) through the vent conduit when the valve is in the closed position. The valve may be positioned, e.g., within the conduit, such that it lies below the exterior surface of the hull. For example, the valve may include a valve housing, which may form at least a portion of the vent conduit. The valve housing may be mounted to the hull such that is extends downward from the hull. The valve may also include a valve barrier which is movable in relation to the housing between the open and closed positions. The valve housing may be configured to substantially enclose moving components of the valve (e.g., the valve barrier). As such, when operatively mounted to the hull, the entirety of the valve, regardless of whether it is in the open or closed position, is located below the exterior surface of the hull thereby maintaining the vessel's hull profile.

In some embodiments, the vent assembly also includes a damper which is configured to selectively modulate (e.g., to increase or decrease) the air flow through the vent conduit. In some embodiments, the damper may be positioned downstream or below the valve and thus selectively fluidly sealing the valve may avoid ingress of fluids (e.g., water) into the damper and reduce the risk of damage to the damper. The valve of the low-profile vent assembly may be implemented using any suitable flow control device that is capable of providing a fluid-tight seal that substantially prevents the passage of a fluid (e.g., water or air) across the barrier of the valve. The damper may be implemented using any suitable gas flow control device that is capable of modeling (e.g., increasing and decreasing as desired) and/or substantially blocking or sealing the passage of gas across the damper. As such a vent assembly according to the present disclosure may operatively couple any suitable fluid flow control device and any suitable gas flow control device, in some embodiments in series within a conduit that connects the internal space (e.g., dry compartment of a boat) to the exterior (e.g., an exterior of the hull of the boat) via a vent opening (such as an opening formed in the hull of the boat). In some such embodiments, the passages of the valve and damper may be coaxially aligned. In other embodiments, the valve and damper may be coupled in parallel, for example by not having the respective flow passage of the valve and the damper axially aligned but being arranged to extend along adjacent (e.g., parallel) axes.

FIG. 1shows an illustration of a boat100, which has a hull216and an internal compartment210defined within the hull216. The internal compartment210may be any dry compartment or area of the boat, such as an engine compartment, electronics room, weapon systems room, a crew cabin, a cargo area, etc. One or more openings in the hull216, such as the air intake202and the air outlet214, which provide air from the ambiance (e.g., from the exterior of the boat) into the internal compartment210and allow air to exit the internal compartment210, respectively, may provide the internal compartment210in communication with the exterior the hull216.

The internal compartment210may be an engine compartment212, as shown inFIG. 2, or other machinery space. The engine compartment212houses components of the boat's propulsion system208, such as one or more engines, which may include an internal combustion engine, one or more electric motors, at least one energy storage device such as a battery or capacitor, and/or other energy generation or storage components (e.g., a nuclear reactor, a jet engine, or others). While embodiments of the low profile vent assembly are described here in the context of fluidly-sealing an internal compartment210of a boat, the vent assemblies herein may be used in other application, such as for venting enclosed spaces or compartments of any other type of vessel or industrial facility. In the present example of a boat100, as shown inFIG. 1, the internal compartment210may additionally or alternatively house electronics such as navigation equipment, radar systems, vehicles adapted for use on land or water, weapons systems, or countermeasures. The internal compartment210may house or enclose other devices that may require air to operate and/or which generate heat to be dissipated. For example, the internal compartment210may be a crew compartment adapted to house people or animals. In some embodiments, a crew compartment may be ventilated according to the methods and systems disclosed herein.

In a boat100that has low freeboard or which may selectively be operated in a low freeboard state (e.g., through selective ballasting), vent openings in the boat's hull216, such as air inlets or intakes, air outlets or other similar vent openings, can be vulnerable to the ingress of fluid (e.g., water) thus potentially becoming downflooding points that can affect the seaworthiness of the boat100, in either operational and damaged condition. A low freeboard, in the context of the present disclosure, may refer to a state or configuration of the boat in which the freeboard of the boat is approximately equal to or below the height of a wave or other water disturbance in which the boat is designed to operate. In some cases, it may be advantageous to provide an opening on a surface of the hull216, such as on the deck206of the boat100as shown inFIG. 1, which may minimize adverse impact to the observability profile of the boat. However such opening may increase the risk of flooding of the boat100, as such openings are more likely to be exposed to contact with or submersion under water.

Accordingly a low profile vent assembly200with a fluid-tight ventilation closure203is described here, which is configured to selectively provide a fluid-tight seal across the barrier of the vent assembly. The low profile vent assembly200may be configured to selectively fluidly seal a vent opening, such as the vent opening in a boat (e.g., a vent of the engine compartment212such as air intake202or air outlet214) while maintaining a low profile by substantially eliminating any structures projecting from the outer surfaces of the outer hull (e.g., from the outer surface of the deck206).

FIG. 1Billustrates a vent assembly200according to the present disclosure, which may be used across a vent of an internal compartment210of the boat100inFIG. 1A. The vent assembly200shown inFIG. 1Bincludes a vent conduit201connecting an opening213in an exterior surface222, such as an exterior hull216surface of a boat100, to an internal compartment210, such as a dry compartment of the boat100. The vent conduit201may have a longitudinal axis205that is substantially parallel to the flow of gas through the conduit. The vent assembly200shown inFIG. 1Balso includes fluid-tight ventilation closure203with a valve portion or simply a valve230and a damper portion or simply damper240. The valve230is operable to provide a fluid tight seal, when provided in a closed positon, such as to substantially prevent the passage of a fluid (e.g., water or any other liquid) through the valve.

The vent assembly200includes a damper240operable to modulate (e.g., increase and decrease) the flow of a gas (e.g., air) through the damper240and in some cases substantially block the passage of the gas (e.g., air) through the damper240, which may provide a fire mitigation function. The valve230and damper240are arranged in series, with both the valve230and the damper240positioned substantially completely below the surface222. As shown inFIG. 1B, the entirety of the valve230and the damper240may be located within the compartment210. The valve230and the damper240are mounted below the surface222such that they extend downward into the cavity defined by the hull206, rather than projecting from any exterior surface of the hull216such as surface222.

The valve230may include a housing232, which may be mounted to the surface222such that it lies below the surface222. The housing232defines a passage233which forms a portion of the vent conduit201. The valve230includes a barrier mechanism or simply barrier234, which is movably coupled to the housing to enable actuation of the valve230between the open and closed positions. The type and articulation of the barrier mechanism234may be different in different embodiments, based on the type or structural arrangement of the valve230used. For example, in some embodiments, the barrier mechanism234may be configured to translate relative to the housing232(e.g., up and down within the vent conduit201along the longitudinal axis205) between the open position and the closed position. In some such embodiments, the housing232may be a cylindrical tubular housing, the length of which may define the height of the valve230. The barrier234may be cylindrical block or plug, which is threadedly coupled to the cylindrical tubular housing, enabling the cylindrical plug to be translated along the length of the housing and thus up and down in relation to the height of the valve. An example of a valve having this type of configuration is described further with reference toFIGS. 4-6.

In other embodiments, the barrier234may pivot relative to the housing232to provide the valve between the open and the closed positions. For example, the barrier234may pivot about a transverse axis207between open and closed positions. The transverse axis207may be orthogonal to the longitudinal axis205of the conduit201. The barrier234may be implemented as a plate (e.g., a disk in the case of a cylindrical housing) having a length dimension (e.g., a diameter of the disk in the case of the circular embodiment). In some such examples, the barrier234may be a rotatable plate configured to rotate or pivot about an axis that runs perpendicular to the height dimension of the valve230. The barrier234may be pivoted off an edge of the plate (e.g., as in the example inFIG. 7) or it may be pivoted about a central location of the plate (e.g., in the case of a butterfly-type valve). In some embodiments, the housing232and the barrier plate234may have a cylindrical/circular geometry. In other embodiments, the barrier plate234may have a non-circular geometry. The barrier plate234and the tubular housing may have a rectangular shape, as long as the cross section and dimensions of the housing232are selected to receive and accommodate rotation of the barrier plate234within the housing232. The housing232may be sufficiently large to substantially fully enclose the barrier plate234in its open position. For example, the length211of the housing232may be equal to or greater than the length209of the plate234such that the plate remains fully enclosed within the housing232. In other embodiments, the length of the housing232may be less than the length of the barrier plate234as long as any portion of the movable barrier plate234, when articulated either to the open or closed position remains substantially flush with or below the outer surface222.

In some embodiments, the vent assembly200may include a drain system or simply drain that includes a drain conduit252fluidly connected to the vent conduit201and to the exterior of the hull216to allow for fluid that accumulates above the barrier234to drain to the exterior of the hull216rather than into the internal compartment210. In some such examples, the opening of the drain conduit252may be elevationally above the barrier234. As shown inFIG. 1B, the drain conduit252may be fluidly connected to the housing232of valve230at a location between the opening213and the barrier mechanism234.

As shown inFIG. 2, the air outlet214can be a downflooding point218for boat100in certain operational conditions such as when the boat is operating in low freeboard mode. In various embodiments described herein, a low profile vent assembly200is operatively associated with an opening in the outer hull216of the boat100, such as to reduce or prevent the ingress of fluid (e.g., water) into the opening, which may be an intake such as the air intake202or a vent such as air outlet214.

In the example inFIG. 2, in which the internal compartment210is shown as an engine compartment212, the low profile vent assembly200is associated with the opening214that serves as an air outlet214. In some embodiments, a low profile vent assembly200may additionally or alternatively be provided at any other openings associated with the engine compartment such as the air intake202. The air intake202is operatively arranged to couple the internal compartment210to the exterior of the hull216such as to allow air to pass from the exterior of the hull216into the internal compartment210. The air entering through the air intake202may optionally pass through an air intake plenum204before entering the internal compartment210. The air intake plenum204may be configured to collect and direct the air entering from multiple hull openings (e.g., one or more air intakes) into the internal compartment, here the engine compartment212. In some embodiments, the air intake plenum204may operatively distribute air from one or more openings into one or more internal compartments of the boat100. In this illustrated example, air entering through intake202and flowing into the engine compartment212may provide air for operation and/or cooling of the propulsion system208such as by providing air to a combustion engine and/or to carry away heat produced by the propulsion system208. Air may exit the internal compartment210and be discharged to the exterior of the hull216through another opening, here the air outlet214, which in this example is provided with a fluid tight ventilation closure200. Thus, air exiting the internal compartment210passes through the fluid tight ventilation closure200as it exits through the opening214. In the embodiment shown inFIG. 2, the intake202is located at a longitudinally forward location of the hull and the internal compartment210, which is shown here as extending along a portion of the length of the boat100. As such the intake202is forward of the outlet214, which may facilitate a better airflow through the internal compartment210, e.g., as the boat200moves forward as indicated by arrow215. In the embodiment shown inFIG. 2, the fluid tight ventilation closure200, which in this example is associated with the outlet214, is located aft of the intake202and/or at an aft end of the internal compartment210. In other embodiments, the low profile vent assembly200can be associated with other openings and/or located in other positions of the internal compartment210, such as a fore position. In various embodiments, low profile vent assembly200can be located at any position to the port or starboard of a midline of the boat100. In the embodiments shown in the figures, the low profile vent assembly200is located at an air outlet214. However, a low profile vent assembly200can be located at an air intake202, or at an air outlet214and an air intake202without departing from the scope of the present disclosure.

In some embodiments, the low profile vent assembly200includes at least one air flow control device (e.g., damper312), a fluid-tight ventilation closure203, and a drain system320. The fluid-tight ventilation closure203may include a valve304. In the embodiment shown, the low profile vent assembly200is coupled to an air mover308. In other embodiments, the low profile vent assembly200might not be coupled to an air mover308, or an air mover308might be present elsewhere in the internal compartment210.

A valve refers to any device selectively actuated by an actuator to start or stop the flow of fluid through a conduit, such as a butterfly, gate, knife, ball, globe, pinch, plug, flap, diaphragm, or other similar device according to the present disclosure. The valve304is fluid tight, preventing the ingress of water into the engine compartment212when in a closed position. In the open position, the valve304allows discharge air220to pass out of the engine compartment212. The valve304can be actuated by any suitable actuator. As illustrated inFIG. 3, the valve304has a movable barrier234. Spool portions302,306, or310can be used to couple the components of the low profile vent assembly200to one another and/or the boat100. In some embodiments, the spool portions302and306may couple to a valve housing, or may be integral with the valve304housing. The spool portions302,306and valve housing may be sized to fully accommodate the barrier234irrespective of the position of the barrier234(e.g., open, closed, or anywhere between open and closed positions). For example, in some embodiments, the valve304may be implemented as a butterfly type valve which is coupled to the hull and downstream components using one or more spool portions302,306to provide a sufficient length of the housing of the valve. In other embodiments, the spool portions302,306(above and below) may be integrated with the central portion of the housing to which rotatably supports the valve barrier234. In some embodiments, fewer or no spool portions302,306, or310are used. For instance, embodiments that utilize a valve304other than butterfly valve may not be equipped with spool portions302,306, or310. The components of the low profile vent assembly200can be either welded, clamped, bolted, screwed, tied or glued together.

In the embodiment illustrated inFIG. 3, the damper312includes a plurality of vanes314. The vanes314can rotate about respective longitudinal axes to move between open and closed positions. The vanes314can take any rotational position between fully open and fully closed positions. Thus, the vanes314can modulate or control the amount of gas (e.g. air) flow through the internal compartment210. In a more closed position, the vanes314tend to cause relatively less air to flow through the internal compartment210. Likewise, in the more open position, the vanes314allow relatively more air to flow through the internal compartment210. Thus, the damper312can modulate a flow of air through the internal compartment210. The vanes314can be actuated by any suitable actuator. “Actuator” refers to any device that converts energy from one form (such as pneumatic, hydraulic, electrical, or stored elastic energy) into motion, such as a motor, servo, belt or gear drive, hydraulic or pneumatic actuator, solenoid, power screw, spring or other resilient element, or a combination of the above.

In a preferred embodiment, the damper312is a fire-rated damper. A fire damper312prevents the spread of fire, and in some embodiments smoke, throughout the boat100. The fire damper312, by way of reducing or stopping air flow through the engine compartment212, can starve a fire of oxygen needed to burn, and thus act to suppress or extinguish a fire.

In the event of a fire, the damper312is automatically shut by an actuator to prevent or reduce air ingress into the engine compartment212. A fire damper312may be activated by a variety of sensors or actuators. In some embodiments, the fire damper312is activated by a sensor that detects a rise in temperature in the engine compartment212to above a certain threshold, or detects a time rate of temperature rise and generates a control signal to actuate an actuator to close the damper. In another embodiment, the fire damper312is activated by a smoke detector. In another embodiment, the fire damper312is activated by a flame detector that senses certain wavelengths of light such as ultraviolet or infrared light. In another embodiment, the fire damper312is activated by a thermal camera. In another embodiment, the fire damper312is activated by an emergency activation button, pressed by a person on the boat100, such as an emergency stop button. In another embodiment, the fire damper312is activated by a general fire suppression system in the boat100.

The drain system320drains water or other liquid that may ingress into the low profile vent assembly200. Such water may ingress due to splashing of water outside the boat100during operation, water that ingresses as the valve304is closing before the valve304is made fluid tight, or partial or total failure of the valve304. Although shown schematically, the drain system320can include passages or conduits324within or connected to the components of the low profile vent assembly200. The conduits324may collect ingress water to a common point for disposal or processing. In some embodiments, the drain system320includes a pump322that discharges collected ingress water outside the boat100.

The drain system320may be adapted to remove two phase fluid mixtures, such as mixtures of water and air, such as by including one or more deaerators. In some embodiments, the drain system320may be adapted to operate when only gases, such as air, are present without damage. In some embodiments, the drain system320has multiple fluid collection points, such as shown for example inFIG. 3, with an upper collection point329disposed near an upper surface of the barrier234, and a lower collection point331associated with a baffle323. When the barrier234is in a closed position, fluid such as a liquid, may collect above the barrier234. Such liquid may be collected at the collection point329and directed into the conduit324for disposal or processing by the pump322. In some embodiments, the drain system320includes baffles such as baffles321and323disposed within a spool portion, such as the spool portion306and/or the air mover308. The baffles321and323direct liquid that has ingressed into the low profile vent assembly to collection points (e.g., collection point331) for removal and disposal by the drain system320. For example, as shown inFIG. 3, if a fluid such as water enters the low profile vent assembly200, it may contact the upper baffle321and drip or run by gravity off the baffle321and onto the baffle323. The baffle323directs the liquid to the collection point331at the intersection of the baffle and the shroud of the air mover308. From the collection points, the liquid (and possibly a non-liquid fluid such as air) enters the conduit324and is withdrawn by the pump322for disposal (e.g., to a bilge, or is expelled from the boat).

In some embodiments, the flow of fluid through the conduit324is controlled by one or more valves, such as valves325and327that receive fluid from the collection points329and331, respectively. The valves325,327may allow the flow of fluid from the collection points329,331when open, and prevent it when closed. The valves325,327may be controlled together, such that they are both open or closed together, or they may be operated independently. In some embodiments, a valve may regulate the flow of fluid through the conduit, allowing flow to increase or decrease as desired. In some embodiments, one valve may control the flow of liquid to more than one collection point. In other embodiments, the flow of liquid from some collection points may be controlled by a valve, while the flow from other collection points may not be controlled by a valve.

The boat100can include a number of devices and systems that automatically detect the ingress of water into the low profile vent assembly200or the internal compartment210, or the threat of such ingress, and automatically close the fluid-tight ventilation closure203. In some embodiments, the detection of ingress water can be manual, such as being sensed by a person on the boat100.

In some embodiments, the boat100includes a water infiltration sensor316. A water infiltration sensor316detects ingress water that has entered the low profile vent assembly200. In some embodiments the detection of water ingress is automatic. A water infiltration sensor316generates a signal in response to the detection of water. The signal may be sensed by a controller such as a processor that generates a control signal in response, and the control signal may cause an actuator to actuate to close the valve304. The boat100can include a water infiltration sensor316that includes a conductivity sensor that detects the presence of an electrical current between two conductors caused by the presence of water. In other embodiments, the water infiltration sensor316is a float sensor that detects an accumulated volume of water in a vessel or conduit, such as a vessel associated with the drain system320.

As shown inFIG. 3, the discharge air220first passes through the damper312. The internal compartment210is connected to the damper312. The discharge air220may be pulled out of the internal compartment210by an optional air mover308. The discharge air may then pass through a valve304, when the valve304is in an open position. Although in the embodiment shown inFIG. 3, the damper312, air mover308, and valve304are shown in a particular order with respect to the flow of the discharge air220, other arrangements or orders of the components of the low profile vent assembly200are contemplated within the scope of the present disclosure.

The air mover308moves air through the internal compartment210. Typically, an air mover308creates a vacuum at its intake, and a positive pressure at its outlet, thereby causing a movement of air through the air mover308. As shown in the embodiment ofFIG. 2, the air mover308pulls fresh air into the internal compartment210and discharges discharge air220out of the internal compartment210. Arranged in this manner, the air mover308draws a vacuum relative to the surroundings. In other embodiments, the air mover308can be arranged to pull fresh air in through a low profile vent assembly200and push that air into the internal compartment210. Arranged in this manner, the air mover308pressurizes the internal compartment210. In various embodiments, the air mover308is a fan, blower, compressor, venturi, turbine, or the like. The air mover308can be an axial fan or an centrifugal fan.

In some embodiments, the boat100can include a motion sensor318that detects motion or position information of the boat100, such as, angular or linear motion or position of the boat100. In some embodiments, the motion sensor318can detect listing, pitching, yawing, or rolling of the boat100. The motion sensor318can detect when the boat100has rolled or pitched beyond a limit with respect to a horizontal axis that runs athwartships, or an axis that runs along a longitudinal midline of the boat100. In some embodiments, the motion sensor318can detect that the boat100has yawed beyond a limit with respect to an axis that runs vertically through the boat100. The motion sensor318can, in some embodiments, detect any one, two, or three of roll, pitch, or yaw. In some embodiments, the motion sensor318can detect linear motion such as surging, swaying, or heaving of the boat100. In some embodiments, the motion sensor318is an accelerometer or similar device that can detect the acceleration, velocity, and/or position of the boat100, and/or changes to the same. In other embodiments, the motion sensor318is a gyroscope, or similar device.

Information about the motion or position of the boat100such as detected by the motion sensor318can be correlated to, or used to determine that, the low profile vent assembly200is at risk of downflooding. In some embodiments, motion or position information can be combined with draught or freeboard information to determine when the low profile vent assembly200is at risk of downflooding. Such information may be used, such as by a controller or processing element, to generate a signal in response to the risk of downflooding. The controller may generate a control signal in response, and the control signal may cause an actuator to actuate to close the valve304.

If the low profile vent assembly200becomes a concern for water ingress and stability/flooding, for instance as detected by the water infiltration sensor316or the motion sensor318, or manually, an actuator can be enabled to close the fluid-tight ventilation closure203, for instance by closing a fluid tight valve304. When the condition that caused the concern of downflooding passes, the fluid-tight ventilation closure203can automatically or manually re-open.

In some embodiments, two or more low profile vent assemblies200can be located at port and starboard sides of the boat100. Thus, if the boat100rolls to port, fluid-tight ventilation closure203of the port-side low profile vent assembly200can close, and the starboard fluid-tight ventilation closure203of that low profile vent assembly200can remain open, allowing air to continue to pass through the internal compartment210. Likewise, if the boat100rolls to starboard, the fluid-tight ventilation closure203of the starboard-side low profile vent assembly200can close, and the fluid-tight ventilation closure203of the port side low profile vent assembly200can remain open, allowing air to continue to pass through the internal compartment210.

FIG. 4is a cross-section view through a portion of the deck206illustrating an embodiment of a valve400suitable to implement the valve304ofFIG. 3of a fluid-tight ventilation closure203and suitable for use in a low profile vent assembly200according to the present disclosure. As shown inFIG. 2, the valve400may be operatively associated with engine compartment212to selectively seal a ventilation port such as the air outlet214or the air intake202. The valve400may be positioned across an opening in the vessel's hull which serves as an air outlet214. For example, the valve400may be inserted into an opening defined in an outer surface404of the deck206(defined in this embodiment between welds402).

In the present example, the valve400has a generally cylindrical construction, however in other examples, other suitable non-cylindrical geometries may be used. For example, the valve400may include a tubular section extending into the engine compartment212, or another part of the fluid-tight ventilation closure203that has an ovular, rectangular or other regular or irregular transverse geometry, and may be operatively associated with a block, shaft, or plug that has a corresponding transverse geometry for cooperating fit within the tube. The valve400may be configured to be coupled (e.g., fixedly or rigidly coupled) to the deck206.

In some examples, the valve400may have a peripheral flange406extending peripherally around the air outlet214. The air outlet214or air intake202can be a substantially circular hole or aperture defined in the deck206or the flange406that allows fluid communication from the peripheral inner surface408of the valve400to the outer surface404of the deck206. In other embodiments of valves, the descriptions herein of an air outlet214are equally applicable to an air intake202; the air outlet214is used to enhance brevity and clarity. The valve400may be fixed to the deck206(or other hull surface) via the flange406. The air outlet214may be a screen with a plurality of air channels (i.e., holes, gaps, vent passages, or openings) that function as air outlets. The air outlet214may be rigidly attached to the adjacent portions of the outer surface404of the deck206, such as, for example, by welds402, fasteners, rivets, interlocking parts, or any other type of attachment mechanism for rigidly coupling components that is known in the art. The valve400may be coupled to the boat hull such that the outer surface434of the valve400and outer surface404of the deck206are substantially coplanar, thereby forming a substantially continuous deck surface substantially free of any gaps, steps or other discontinuities aside from openings for the air channels. In other embodiments, the air outlet214can be integrally formed with the deck206as a single piece For example, the deck206may include a protrusion410, and other features of the valve400.

The peripheral inner surface408may include a protrusion410extending around the peripheral inner surface408. The protrusion410may be referred to as a sealing ridge or circular sealing or engagement member that surrounds the peripheral inner surface408. The protrusion410may be part of a sealing interface, as described in further detail below and in other descriptions herein. The protrusion410may have a pointed cross-section and may therefore be referred to as a “knife edge,” wherein the pointed cross-section forms a sharp edge or ridge configured to come into contact with, and apply focused pressure against, a resilient seal430on the shaft structure420, as explained in further detail below and in other descriptions herein.

A cylinder structure428may extend inward from the flange406at the peripheral inner surface408. Therefore, the cylinder structure428may be positioned within the engine compartment212at a surface. In some embodiments, the cylinder structure428can be formed within a channel or conduit that connects the interior of the engine compartment212to the deck206. The peripheral inner surface408may be a top inner surface of the engine compartment212(e.g., the topmost outer surface404of the deck206).

A top end of the cylinder structure428may include a passage portion412.FIG. 6shows a section view of the valve400in an open position with air passing through the passage portion412, The passage portion412extends downward from the peripheral inner surface408, The passage portion412includes a series of circumferentially spaced apart openings602that provide fluid communication between the engine compartment212and the air outlet214. The shape and positioning of these circumferentially spaced apart openings602may make the passage portion412have a generally castellated shape with a set of wall portions436separated by the circumferentially spaced apart openings602. In this embodiment, the passage portion412has eight circumferentially spaced apart openings602spaced around its sides, but fewer openings such as just one opening, may be sufficient to operate the valve400. By having eight circumferentially spaced apart openings602or another number of multiple large openings, it may be easier for air that is in the engine compartment212to pass through the passage portion412on all sides of the passage portion412, thereby increasing ventilation and/or reducing the power of the air mover308. The valve400may include a housing232that contains the cylinder structure428. The housing232may define an annular space between it and the cylinder structure428through which fluid flows (e.g., air, which can be intake air, or as illustrated, discharge air220).

In some embodiments, some or all of the circumferentially spaced apart openings602may extend from the peripheral inner surface408to the lower end414of the cylinder structure428. In some embodiments, some or all of the openings may extend along less than the entire longitudinal dimension of the passage portion412. The circumferentially spaced apart openings602can extend along a portion of the top end of the passage portion412, a bottom end thereof, or a middle portion thereof. By positioning the circumferentially spaced apart openings602at a top end of the passage portion412, the openings can be positioned at a topmost edge of the valve400and at the topmost end of the engine compartment212.

A shaft structure420may be positioned within the cylinder structure428and may move relative to the cylinder structure428and relative to the air outlet214. Thus, the cylinder structure428can laterally surround the shaft structure420. The shaft structure420may translate vertically upward and downward within the cylinder structure428, as illustrated inFIG. 4andFIG. 6.

A resilient seal430, such as an o-ring, rubber seal, flexible plastic seal, or similar structure, may extend around the top end of the shaft structure420in a position on the shaft structure420that corresponds to the protrusion410on the peripheral inner surface408of the air outlet214. SeeFIG. 5, which is a detailed view of the area withinFIG. 4. A retaining groove502, channel, or depression at the top end of the shaft structure420may hold the resilient seal430in place on the shaft structure420as the shaft structure420translates or rotates within the cylinder structure428, as seen by comparingFIG. 4andFIG. 6.

When the shaft structure420is at the top of its range of travel and the resilient seal430is in contact with protrusion410, the shaft structure420(and the valve400as a whole) may be referred to as being a closed or sealed state, as shown inFIG. 4. The contact between the resilient seal430and the protrusion410may be fluid tight, airtight, or otherwise fluid tight in a manner that ensures that water does not ingress into the internal compartment210of the boat100. Fluids, whether air or water, cannot pass through the circumferentially spaced apart openings602when the valve400is in the closed state. Accordingly, the internal compartment210can be prevented from taking on water through the air outlet214while the valve400is in the sealed state.

When the shaft structure420is at a lower position along its range of travel, such as in the position shown inFIG. 6, the resilient seal430is not in contact with the protrusion410, and the shaft structure420and the valve400as a whole may be referred to as being in an open, venting, or unsealed state. InFIG. 6, the section view is rotated relative to the section view ofFIG. 4, to show circumferentially spaced apart openings602and how they provide fluid communication between the exterior and interior of the cylinder structure428. The separation of the resilient seal430from the protrusion410and the presence of the circumferentially spaced apart openings602in the passage portion412of the cylinder structure428may allow discharge air220air to flow from the area inside of internal compartment210surrounding the cylinder structure428through the circumferentially spaced apart openings602, as shown by the flow arrows inFIG. 6.

Thus, the shaft structure420may be rotated to translate between the closed state and the open state of the valve400. For example, the shaft structure420may have a longitudinal axis422about which the shaft structure420rotates, and a set of mating threads416that mate with threads418on the cylinder structure428may guide the shaft structure420upward and downward between the sealed and unsealed configurations of the valve400as it rotates relative to the cylinder structure428. The threads416may be male threads disposed on an outer surface of the shaft structure420. The threads418may be female threads disposed on an inner surface of the cylinder structure428. The threads416and418may threadedly couple the shaft structure420to the cylinder structure428to effectuate the linear translation of the shaft structure420relative to the cylinder structure428by relative rotation of the shaft structure420to the cylinder structure428. An upper gasket424and a lower gasket426may be positioned on opposite ends of the mating and engaged threads416and threads418prevent ingress of debris or other contaminants between the threads. One or more of the gaskets can be referred to as wiper seals that are configured to clean off the threads416,418as they rotate in contact with the appropriate lower gasket426or upper gasket424. In the embodiment shown, the lower gasket426and upper gasket424are located in respective recesses at ends of the cylinder structure428. In an alternative embodiment one or both of the upper gasket424and/or lower gasket426are located in the shaft structure420.

In the embodiment shown, the shaft structure420and the cylinder structure428include mating and engaged threads416and threads418, respectively, and the valve400is suitable for actuation by an actuator such as a power screw, servo, motor, or other rotary actuator. An actuator such as, for example, a motorized shaft or lever, may be mounted to the shaft structure420and may be used to induce rotation of the shaft structure420relative to the cylinder structure428. The actuator may be operated remotely, thereby allowing the valve400to be opened and closed by a user that does not have manual access to the internal compartment210. In this way, the air flow through the internal compartment210of the boat100can be manipulated by a person without having to access the fluid tight ventilation closure200.

Thus, the low observability characteristics of the shape and freeboard configuration of the boat100can be preserved as the fluid-tight ventilation closure203of the low profile vent assembly200is operated. In other words, a crew member does not need to emerge from the inside of the boat100in order to operate the fluid-tight ventilation closure203. In some embodiments, the actuator is positioned entirely within internal compartment210, but in some cases the actuator can be only partially within the internal compartment210, such as, for example, by having a rotatable link that extends to the shaft structure420at one end and having a motor joined to an opposite end of the link external to the internal compartment210.

In other embodiments, the shaft structure420may not include threads418and the cylinder structure428may not include threads416. The shaft structure420and the inner surface of the cylinder structure428may then have relatively smooth cylindrical surfaces. Thus, the shaft structure420can slide linearly in the cylinder structure428without twisting, such as would be induced by threads, much as a piston slides within a cylinder. Such embodiments may be suitable for actuation by an actuator such as a hydraulic or pneumatic ram, solenoid, or other linear actuator. In such embodiments, the lower gasket426and the upper gasket424may be lip seals that are configured to wipe or clean the shaft structure420or the cylinder structure428. Some such embodiments may be faster to actuate than the embodiment shown inFIG. 4andFIG. 5.

FIG. 7is a side section view of an alternate embodiment of a valve700for use in a fluid-tight ventilation closure203of a low profile vent assembly200. The valve700is suitable to implement the valve304ofFIG. 3and is suitable for use in a fluid-tight ventilation closure203according to the present disclosure. The valve700may be referred to as a pivoting valve or door valve. The pivoting valve700may close or seal off the air outlet214using a pivotable cover plate708. The air outlet214may be mounted to the deck206using the same techniques as described above. The peripheral inner surface408of the valve700may be coplanar with the inner surface442of the deck206. The valve700or the deck206may comprise a set of protrusions702that correspond to resilient members706in or on the cover plate708. The set of protrusions702and resilient members706may have shapes and functions similar to the protrusion410and resilient seal430of valve400to provide a sealing interface. As shown inFIG. 7, a set of protrusions702may be concentric and correspond to a set of three concentric resilient members706, and when the cover plate708is in a closed position as indicated by the closing motion arrow714, the set of protrusions702may contact and form a seal with the resilient members706. Using a set of protrusions702and resilient members706may provide improved reliability for the sealing function of the cover plate708since failure of a seal between one of the set of protrusions702and one of the resilient members706may be compensated for by one or more of the other sets of sealing interface components.

The cover plate708may be mounted to the deck206by a hinge712. The hinge712may be positioned at an extreme end of the cover plate708so that the rotation of the cover plate708may rotate the entire cover plate708away from the inner surface408of the air outlet214. The cover plate708is shown in an unsealed or open condition inFIG. 7. As indicated by the arrows inFIG. 7, when the cover plate708is rotated about the hinge712, air may escape through the air outlet214. The cover plate708may be configured to rotate about 90 degrees between the closed position and the fully open position shown inFIG. 7. An airtight, fluid tight, or other fluid tight interface may prevent the ingress of water when the cover plate708is in the closed position. Although the cover plate708is shown inFIG. 7as being rotatable about a pivot axis that extends perpendicular to the page, in some embodiments, the cover plate708can be configured to rotate about a pivot axis that extends vertically inFIG. 7and thereby rotates away from the air intake202by pivoting into or out of the page.

In some embodiments, the cover plate708may be connected to an actuator at an actuator connection point710. For example, a telescoping hydraulic or pneumatic arm, a geared arm, a cam-and-follower mechanism, a motorized or manual lever, a power screw, or similar actuation devices, and combinations thereof may apply a force to the cover plate708at the actuator connection point710to cause the cover plate708to rotate about the hinge712between the open position ofFIG. 7and a closed position as indicated by the closing motion arrow714. The cover plate708rotates inward, i.e., into the interior of the internal compartment210and therefore does not affect the appearance, aesthetics, or other observability characteristics of the air outlet214or the outer surface404of the deck206.

From the foregoing it will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made while remaining within the scope of the claimed technology.

Examples described herein may refer to various components as “coupled” or signals as being “provided to” or “received from” certain components. It is to be understood that in some examples the components are directly coupled one to another, while in other examples the components are coupled with intervening components disposed between them. Similarly, signal may be provided directly to and/or received directly from the recited components without intervening components, but also may be provided to and/or received from the certain components through intervening components.

Various examples of the present disclosure have been described in detail above to facilitate an understanding of the invention. It will be recognized by those skilled in the art that many variations to the examples described are possible without departing from the scope and spirit of the invention disclosed herein, and that the scope of the claimed invention is defined by the claims listed below. The terms “including” and “having” as used in the specification and claims shall have the same meaning as the term “comprising.”