This application relates to the marine field of dry docks where a marine vessel (boat) is substantially removed from contact with water, by removing the water, rather than removing the vessel.

Background of the Invention

In the field of marine moorage for watercraft (vessels) such as boats, jet skis, and similar floating vessels, it is often desired to reduce direct contact between the hull of the watercraft and the water in which the vessel floats. One obvious reason for this is to reduce any likelihood of the vessel taking on water, potentially sinking, due to a hole through the hull of the watercraft. For example, through-hull fittings periodically fail, resulting in water entry into the watercraft. If such water entry occurs when the watercraft is not occupied, or if any bilge pump fails, or if the bilge pump is

inadequate to the volume of water entering the watercraft, etc., then there is a significant likelihood that the watercraft may sink or be damaged. In addition to potential water entry problems, even though the portion of the watercraft below the water line may be coated by a specific covering such as paint which is designed to retard marine growth thereupon, none of such coatings (paints) are perfect. In a saltwater environment for example, algae, fungus, barnacles, mussels, and other marine life may attach themselves to the hull of the watercraft and grow there. This growth not only is aesthetically displeasing, but also negatively impacts the performance of the watercraft in motion and results in high maintenance costs, as the vessel must be periodically removed from the water, scrubbed, and re-coated. Barnacles especially cause damage as their cement glands often permeate into the hull of the watercraft over time resulting in significant repair cost to remove, and repair the damaged portion of the hull.

Thus, where possible, watercraft are often removed from the water for storage rather than being kept at a dock in the water. This dry storage technique is often expensive and undesirable especially for larger watercraft. In addition, repositioning the watercraft from the dry storage to the water is time-consuming, potentially dangerous, and financially expensive.

US 8739724, the contents of which is hereby incorporated by reference, discloses an inflatable dry dock which allows for dry storage of a vessel without removing the vessel from the water. The dry dock disclosed in US 8739724 comprises an inflatable perimeter float having a port side, a starboard side, and an aft side; and a malleable diaphragm sealed to the port side, starboard side, and aft side of the perimeter float to form a watertight boundary between a watercraft and the water in which the dry dock and watercraft float. The watertight boundary in one form having an inner surface wherein the inflatable perimeter when inflated, and diaphragm in combination are less dense than water, and therefore float The aft side of the perimeter float in one form forming a gate portion which is selectively deflated so as to be more dense than water, and therefore sink below the surface of the water in which the dry dock floats. The gate remains attached to the perimeter float when deflated, and allows water to at least partially fill the watertight boundary such that a watercraft may enter the watertight boundary through the gate.

Once the watercraft enters the dry dock, the gate portion is inflated, sealing off the vessel from the marine environment. A water pump which is in fluid communication with the inner surface of the watertight boundary then evacuates the water from between the inner surface and the watercraft, leaving the vessel to be stored.

A disadvantage of the dock described in US 8739724 is that if the vessel is significantly smaller than the size of the dry dock, or has a non-uniform hull, such as in the case of a multi-hull vessel, a large amount of water remains in the dry dock once it is docked. This water can be pumped out using the water pump, but this is a slow and inefficient process, especially using a relatively low volume pump such as a bilge pump. It is therefore desirable to provide a more efficient process for evacuating the water from the dry dock.

Summary of the Invention

In a first broad aspect the present invention provides for an inflatable dry dock comprising an inflatable perimeter float comprising a gate portion which can be inflated and deflated independently of the remainder of the float, and a malleable diaphragm sealed to the inflatable perimeter float, which comprises one or more, for example two, three, or more, inflatable floor floats which are able to be inflated or deflated independently of the inflatable perimeter float.

Thus, in its various embodiments, the invention provides a floor float

inflation/deflation system which can be in any form including a single or multiple array of longitudinal or lateral inflatable cells or combinations thereof.

The perimeter float and the malleable diaphragm, when each are fully inflated, are less dense than water and form a watertight boundary between an internal region for surrounding the hull or hulls of the water craft and an external region. The gate portion when deflated is more dense than water, thereby sinking to allow access to the internal region for water and watercraft from the external region.

In certain embodiments the inflatable floor floats are inflated by way of an inflation hose or manifold. Inflation of the floor floats may be simultaneously or

independently, for example in a sequential manner.

At least one of the one or more floor floats can be elongate. In some embodiments, an elongate floor float is positioned perpendicular to the gate portion, and may include at least one perpendicular extension. In other embodiments, an elongate floor float is positioned parallel to the gate portion. In certain embodiments, the inflatable dry dock comprises a plurality of elongate floor floats positioned parallel to the gate portion.

The inflatable dry dock may further comprise a water pump in fluid communication with the internal region, for evacuating water from the internal region. In certain embodiments the water pump is an automatically controlled pump which actuates when there is a substantial amount of water within the internal region, and

automatically disengages when there is not a substantial amount of water within the internal region. In certain embodiments the gate portion of the inflatable perimeter comprises weights which are significantly more dense than water.

In a second broad aspect, the invention comprises a method of docking a watercraft in the dry dock as described herein. Such a method comprises the steps a. driving a water craft from the external region into the internal region of the dry dock while the gate portion and floor floats are deflated; b. inflating the one or more floor floats; c. inflating the gate portion, thereby forming the watertight boundary between the external region and the internal region. In certain embodiments the method further comprises the step: d. activating a pump to evacuate water from the internal region.

Steps b, c and d may be automated or may be performed manually. In certain embodiments the steps are sequential in nature. In other embodiments, the steps may be performed with substantial overlap. In certain embodiments, step b may comprise inflating the floor floats simultaneously or sequentially.

Description of the Figures

A preferred embodiment of the invention will now be described, by way of example only, with reference to the figures in which:

FIG. 1 is a side view of one embodiment of the disclosure where the opposing side view is substantially a mirror image thereof.

FIG. 2 is a top or plan view of the embodiment of FIG. 1.

FIG. 3 is a rear view of the embodiment of FIG. 1. Detailed Description of the Invention

In the present description of the invention and in the claims which follow, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated feature but not to preclude the presence or addition of further features in various embodiments of the invention. In addition, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article "a" or "an" thus usually means "at least one".

FIG. 1 shows one embodiment of a floating dry dock 20 with a watercraft 22 therein. The watercraft 22 is described as having a forward or bow portion 24, a stem portion 26 which may include a swim step 28, and a keel. (Extending from the hull 30 in the illustrated embodiment of a watercraft is a rudder 32 commonly used to steer the vessel, a propeller 34, and a shaft 36 connecting the propeller to an engine normally within the watercraft 22. Power driven watercraft may also use a stem drive, or outboard engine. Other watercraft such as sailboats may not have a shaft or propeller but may be driven by sails, oars, paddlewheels, water jet drives, or similar propulsion means. There are many watercraft that have no propulsion means of their own, but rather rely on the propulsion means of other watercraft (such as tug boats) to be moved.

The dry dock 20 in one form comprises a forward or bow portion 38, and a stem portion 40 easily seen in FIG. 1. In FIG. 2, the port side 42 and starboard side 44 can be easily seen and distinguished. Looking back to FIG. 1 , the dry dock 20 of this embodiment generally comprises an inflatable perimeter float 46 which may be internally segregated at multiple points by a bulkhead 48. In one embodiment, transversely aligned bulkheads 50 within the inflatable perimeter tube distinguish a forward part 54 of the dry dock 20, which is nearly constantly inflated, from a gate portion 52, which may be selectively deflated and allowed to sink below the water line 56 to allow the watercraft 22 to enter and exit the dry dock 20. Attached and sealed to the perimeter float 46 is a malleable diaphragm 58. The perimeter float 46 and diaphragm 58 together form a watertight barrier between the internal region 96 of the dry dock (shown as including the outer hull 30 of the watercraft 22) and the external region 98 which comprises the water in which the watercraft 22 and dry dock 20 float

The watertight diaphragm 58 may be formed of polymer impregnated fabric, polymers, watertight or water resistant fabrics or other materials commonly used in the production of inflatable watercraft such as for example polyester reinforced polyurethane. Chlorosulfonated polyethylene (CSPE) synthetic rubber (CSM) commonly sold under the trade name "Hypalon" may also be used. Other materials such as polyvinyl chloride (PVC), polyethylene, polypropylene, and other plastics or plasticized materials may be utilized in both the formation of the diaphragm 58 as well as the perimeter float 46.

The diaphragm 58 includes inflatable floor floats 90. The floor floats may be formed as part of the diaphragm 58 or may be separately fixed to the internal or external surface of the diaphragm. As best shown in Figure 2, the floor floats are inflated by way of a floor inflation hose and manifold 92. In the depicted embodiment the floor inflation hose and manifold 92 has a separate disconnect fitting 94 for an external inflator although it is possible to have a single connector for the gate portion and floor inflation portions which is selectively operated. The floor floats 90 are shown as being placed longitudinally along the bow-aft axis of the boat. However, depending on the nature of the watercraft a number of other configurations can be envisaged.

To aid in connection between the dry dock 20 and the watercraft 22, the mooring dock, pilings, another vessel, an anchor, and/or other secure mooring attachment points, a plurality of mooring beckets 60 are provided which allow attachment of mooring lines (ropes) which may then be attached between the dry dock 20 and the watercraft 22, the mooring dock, another vessel, or other apparatus to form a secure attachment between the dry dock 20 and the other apparatus. Generally, the vessel will be attached directly to the mooring dock through other mooring lines to reduce stress on the dry dock 20, although the watercraft 22 may be attached to the dry dock 20 through the mooring lines on a temporary basis while initially docking the watercraft. The mooring beckets 60 may also provide attachment points for electrical connections, fluid conduits for air entry, and water evacuation. The diaphragm 58 may include a pocket 62, or a plurality of pockets 62, to protect and seal around the rudder(s) 32, propeller(s) 34, and/or shaft(s) 36. Similar pockets may be sized and shaped for outboard motors, sailboat keels, jet drives, and other hull projections. When not required, or for transportation the entire perimeter float can be deflated. The dry dock 20 may also comprise a plurality of handles 88, as shown in FIG. 2, for grasping such as for repositioning of the dry dock 20. The handles 88 may be especially useful in carrying the apparatus when not inflated.

When the watercraft 22 is absent from the dry dock 20, the gate portion 52 and floor floats 90 may be maintained in either the inflated position or the deflated position. If the floats are in the inflated position, then the first step in docking the watercraft 22 is to deflate both the floor floats 90 and gate portion 52.

In one form, the gate portion 52, has a weighted portion, such as a weight tube 64 or plurality of weight tubes 64 which may be heavier than water. When the gate portion is deflated it will pivot about a gate pivot 66 along pivot arc 68 as shown in FIG. 1 to an open position 70. As shown, the weight tubes 64 may be external of the gate portion of the perimeter tube, or they may be internal. In the gate open position, water may flow into the internal region 96, and the watercraft may be driven or pulled into internal region 96. Once the watercraft is in place, air may firstly be pumped back into the floor floats 90 through the floor inflation hose and manifold 92 shown in FIG. 2, which may be connected to a source of pressurised air through disconnect fitting 94. The inflation of the floor floats results in the floats becoming lighter than the water in the internal and external regions and thus lifting the malleable diaphragm 58. In most cases this lifting will be restrained by the diaphragm coming into contact with the hull or hulls of the vessel, although the lifting may also be constrained by the connection between the diaphragm and the perimeter float. As a result of this lifting, a portion of the water in the internal region will be forced out through the gate portion in the open position 70. Air is then pumped back into the gate portion 52 through a gate inflation hose 72 shown in FIG. 2, which may be coupled to a source of pressurized air through a disconnect fitting 74 either on the watercraft, on the moorage dock, or on (in) the dry dock 20. As the gate portion 52 is inflated, it will become lighter than water, pivot about the gate pivot 66 from the open position 70, to a closed position 76 along pivot arc 68. Bulkheads 50 assist in operation of the gate, as they maintain positive air pressure in the forward portion of the perimeter tube 46, while allowing the gate portion 52 to pivot and partially sink below the wateriine 56.

In one form, a first plurality of electrically conductive leads 78 are attached to the inner surface of the watertight boundary (diaphragm 58). These electrically conductive leads are in electric communication with a water pump 82 so as to provide operating power thereto. A second plurality of electrically conductive leads 80 may be attached by an electrical disconnect fitting (not shown) to the first plurality of electrical leads 78 and allows connection of the pump 82 to a power supply on the watercraft 22, or dockside. Manual water pumps may also be used, or the water pump may be inside the watercraft and connected by a tube or through-hull to the area between the hull 30 of the watercraft and the watertight boundary (diaphragm 58).

In one form, the water pump 82 is an automatic, bilge pump which is actuated when in contact with water, and de-activated when a certain amount (level) of water is not present. The water pump 82 is normally connected through a tube 84 to an overboard discharge fitting 86, as shown in FIG. 2, which directs the water from the internal region. In another form, the pump is a dockside pump with a suction hose into the internal region 96 of the dry dock. Such a pump may be controlled by an external load sensing controller and may be driven by mains power.

The source of pressurized air may be external of the perimeter float 46, or may be provided within the perimeter float 46. In one embodiment, an air pump (compressor) is provided within the watercraft 22 and the disconnect fitting 74 is mated to an interoperating fitting on the watercraft 22. In this way, air can be pumped into the gate portion 52 and the rest of the perimeter float 46 without a fluid (air) connection to the mooring dock or other vessel. This also allows the apparatus to be completely portable, as it does not rely on shore power or external connections. Once the gate portion 52 is repositioned to a closed orientation, and the watertight boundary is established around the watercraft, the pump 82 is actuated and the water between the watercraft 22 and diaphragm 58 is then evacuated. If the pump 82 is an automatic type pump, it may be left on (powered) to evacuate rainwater, water from waves splashing into the internal region 96 or water leaking or otherwise entering this region. Once the gate portion 52 is in the closed orientation it is also possible to deflate the floor floats 90. The malleable diaphragm 58 is then lifted by hydrostatic pressure into contact with the clients hull. Alternatively, the floor floats 90 can remain inflated while the watercraft 22 is in position. The steps of inflating the floor floats 90, inflating the gate portion 52 and activating the pump 82 are in one form sequential. However, it will be apparent that the steps could overlap. For example, provided the gate portion remains below the level of the floor floats, the water will flow out of the internal region. Thus the process of inflating the gate portion can begin before the action inflating of the floor floats is complete. Alternatively, there may be a delay between the action of inflating the floor floats and inflating the gate portion in order to allow the water to flow from the internal region.

It will be apparent that, by first inflating the floor floats a large portion of the water can be efficiently removed from the dry dock. This water would otherwise need to be pumped out by the pump. In many situations mains power is not available, thus the pump may be required to run on power from the watercraft. In these situations a high volume pump is not needed. The floor floats of the present invention may allow for the use of a low volume pump whilst still quickly and efficiently removing the majority of the water.

Ideally a dry dock should be tailored to the particular vessel, although the cost associated with this approach is high. An alternative is to manufacture identical docks of the correct approximate size for a group of vessels, thus taking advantage of economies of scale. However, differences in size and hull shape mean that in certain cases a large amount of water will remain in the internal region, resulting in the above described difficulties regarding the pump. Adding floor floats assists in removing this water and thus may present a solution to this problem. In one approach which can cater for vessels having a range of size, configuration and depth of keel, each of the port and starboard sides of the malleable diaphragm comprises a plurality of floor floats. The floor floats may be elongate, and in some embodiments may be positioned parallel to the gate portion, thus forming two arrays which will sit on corresponding sides of the hull or hulls of the vessel. The arrays of floor floats may all be connected to a common compressed air inlet manifold. In some embodiments a section of the malleable diaphragm between the two arrays can be expanded or contracted, for example gathered, to suit the profiles of a range of vessels. Whilst the present invention is illustrated by the embodiment depicted, other variations may exist. Of particular note, while the floor floats are depicted as cylindrical and longitudinal, they may be incorporated in a number of other shapes or orientations depending on the nature of the vessel. For example, the floor floats could be arranged in a substantial V shape around the bow of the vessel, and mapping the shape of the perimeter float, thus facilitating the aft runoff of water from the bow of the dry dock.

Sequential inflation of the floor floats could also achieve a similar effect. By inflating floor floats firstly at the farthest region of the dry dock from the gate portion, and then sequentially inflating floor floats placed incrementally closer to the gate portion, water can be pushed out of the open gate. Such a result can be achieved for example by the use of multiple rows of floor floats. Alternatively the floor inflation hose can be connected to the floor float at the end farthest from the gate portion and the pressure provided can be such that the floor float gradually inflates, with the inflation occurring fastest at the end furthest from the gate portion. In extremely efficient versions of this embodiment it could be envisaged that no pump is required.

Where the watercraft is a catamaran, there is a large cavity between the two hulls, which remains full of a significant quantity of water once the watercraft is positioned in the internal region. By positioning one or more floor floats within the cavity, at least a portion of this water can be displaced by the inflation of the floor floats, leaving less water to be pumped from the cavity. In a certain embodiment a single floor float can be positioned centrally in the internal region, preferably perpendicular to the gate so that it lies between the hulls and when inflated will rise up in the cavity. Alternatively, instead of a single float, multiple floor floats, for example two, can be positioned in a colinear manner. This enables inflation of the floor floats

independently, for example to allow for sequential inflation. Preferably the floor floats are elongate. However, the floor floats may include perpendicular extensions allowing for greater buoyancy and displacement of water. Clearly such an

arrangement can be adapted for other embodiments where a cavity is created, for example a trimaran.

It will be appreciated that the malleable diaphragm will need to rise (and fall) inside the cavity along with the floor floats. In order to ensure that contact of the diaphragm with the hulls does not restrict this movement, the malleable diaphragm can include an additional drape or extension of material which extends as the floor float rises within the cavity. Such an arrangement may be of use in embodiments other than those which have a cavity between hulls.

In most cases it will be that the gate portion will correspond to the stem of the watercrafL However, in certain alternatives it may be that the watercraft is reversed into the dry dock, and thus the gate portion is at the bow portion of the dry dock.

The processes required for docking a boat may be performed or controlled manually, or they can be automated.

It is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to the detail and embodiments described above. Additional advantages and modifications within the scope of the appended claims will readily appear to those sufficed in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' general concept.