System and method to prevent the biofouling of an outdrive

An outdrive engine enclosure having at least one sidewall forming a closed end and an open mouth opposite the closed end is disclosed. The enclosure includes a transom ligature constrictably coupled circumferentially about the at least one sidewall proximate the open mouth, and also includes at least one neck ligature constrictably coupled circumferentially about the at least one sidewall, between the open mouth and the closed end. The outdrive engine enclosure further includes a deployed configuration, where the at least one sidewall proximate the open mouth is constricted by the transom ligature around one of a transom mounting rim and a gimbal housing to form a transom seal that is substantially watertight. The deployed configuration also includes the at least one sidewall being constricted by the at least one neck ligature against the outdrive engine proximate a neck, thereby reducing the volume contained inside the enclosure in the deployed configuration.

TECHNICAL FIELD

Aspects of this document relate generally to preventing the biofouling of an outdrive.

BACKGROUND

Zebra mussels, and other invasive species such as quagga mussels, have rapidly become an expensive problem. Zebra mussels originated from the lakes of Russia and the Ukraine, and have since spread throughout the world. First noted in the Great Lakes in the 1980s, zebra mussels have quickly spread throughout many of the major lakes of the United States. Some estimate the annual cost of dealing with zebra mussels and repairing their damage to be in the hundreds of millions of dollars in the United States alone.

Removing zebra mussels from an entire lake can be problematic. The impact of a poison on the ecosystem of an entire lake, as well as the effect of introducing a large mass of dead zebra mussels, is very difficult to predict. Also, the process of getting regulatory approval for large-scale treatment has been slow. In the meantime, boat owners are left to wage their own battle against biofouling from zebra mussels, quagga mussels, and other invasive species.

It is hard to overstate the negative impact zebra mussels have on the ecology, infrastructure, and property in infested bodies of water. Zebra mussels reproduce quickly; adult females can each produce up to a million eggs a year. The free-swimming microscopic larvae, called veligers, drift in the water before settling onto any hard surface available. With respect to boats, the biofouling is not limited to the exterior surfaces of the hull, engine, and other submerged elements. Veligers that are drawn into, or swim into, engine passages can settle in the cooling system where they can grow into adults, blocking internal screens, hoses, passages, strainers, etc. Such blockages can cause an engine to quickly overheat, and extraction and repair can be very expensive.

Performance advantages and lower cost have led to the popularity of sterndrive boats, also called I/O or inboard/outboard drive boats. The hallmark feature of a sterndrive boat is that the engine is onboard, and the rest of the propulsion system is outside of the boat, passing through the transom, with the flexible connection typically protected by a baffle or bellow device. Although most outdrives can be raised up, sometimes they are still partially in the water; furthermore, an outdrive in the raised position exposes the baffle to weather and UV damage, as well as damage from animals, birds or invasive insects and sharp objects. As such, outdrives are often left in the water when the boat is moored. In zebra mussel infested waters, such exposure can lead to degraded performance and even an inoperative cooling system. While the best way to avoid mussel problems is to remove the boat from the water and rinse it with hot water, this is not always a practical solution.

Traditional methods of preventing zebra mussel growth on drives in the water have relied on using special materials, or coating surfaces with waxy or soapy substances that prevent the veligers from bonding with the surface. However, these methods are problematic, as materials can degrade over time and can be difficult to replace; furthermore, an entire coolant system would have to be rebuilt with these materials in a traditional engine. The use of coatings can be effective, but it can be difficult to determine whether an application was sufficient before mussels have started growing. Also, the use of such substances is not feasible on the internal passages of an engine, such as the cooling system.

SUMMARY

According to one aspect, an outdrive engine enclosure includes a top sidewall, a bottom sidewall, and two side sidewalls coupled to each other and forming a closed end and an open mouth opposite the closed end. The open mouth is sized to simultaneously receive a skeg and a cavitation plate of an outdrive engine. The outdrive engine enclosure also includes a transom ligature constrictably coupled circumferentially about the sidewalls proximate the open mouth, and two neck ligatures constrictably coupled circumferentially about the sidewalls between the open mouth and the closed end. The outdrive engine enclosure further includes a transom section comprising the open mouth, the transom ligature, and a first portion of the sidewalls, the transom section coupled to a neck section along a first junction, the neck section comprising the two neck ligatures and a second portion of the sidewalls. The outdrive engine enclosure also includes a prop section coupled to the neck section along a second junction and comprising the closed end and a third portion of the sidewalls. The enclosure at the first junction narrows along at least a first path and the enclosure at the second junction expands along at least a second path. The outdrive engine enclosure further includes a deployed configuration, the deployed configuration comprising the sidewalls proximate the open mouth constricted by the transom ligature around one of a transom mounting rim and a gimbal housing of the outdrive engine to form a transom seal that is substantially watertight, and further comprising the sidewalls, between the open mouth and closed end, constricted by each of the two neck ligatures against the outdrive engine proximate a neck of the outdrive engine, thereby reducing the volume contained inside the enclosure in the deployed configuration. The neck of the outdrive engine is defined by a smallest circumference around the outdrive engine that passes between the cavitation plate and a cowling above the cavitation plate. Lastly, fluid communication between outside of the enclosure and inside of the enclosure while the enclosure is in the deployed configuration is inhibited sufficient that a veliger extinction capacity within the enclosure outpaces a rate of veliger introduction to the outdrive engine while the enclosure is in the deployed configuration.

Particular embodiments may comprise one or more of the following features. The outdrive engine enclosure may further comprise a plurality of vents proximate one of the two neck ligatures. Each vent may allow fluid communication through the sidewalls when the enclosure is not in the deployed configuration, and may be held closed by the neck ligatures when the enclosure is in the deployed configuration. The outdrive engine enclosure may further comprise at least one veliger inhibitor pocket which may be positioned on at least one sidewall inside the enclosure. The enclosure may also comprise a veliger inhibitor releasably coupled inside each of the at least one veliger inhibitor pocket. Each veliger inhibitor may be one of a deoxygenator and a veliger poison. The sidewalls may consist of PVC coated fabric, and the PVC coating is external to the enclosure. Lastly, the transom ligature and/or the two neck ligatures each may comprise a nylon strap coupled to a buckle. Each nylon strap slidably coupled to the sidewalls through a plurality of loops.

According to another aspect of the disclosure, an outdrive engine enclosure includes at least one sidewall forming a closed end and an open mouth opposite the closed end, a transom ligature constrictably coupled circumferentially about the at least one sidewall proximate the open mouth, and at least one neck ligature constrictably coupled circumferentially about the at least one sidewall between the open mouth and the closed end. The outdrive engine enclosure further includes a deployed configuration, the deployed configuration comprising the at least one sidewall proximate the open mouth constricted by the transom ligature around one of a transom mounting rim and a gimbal housing to form a transom seal that is substantially watertight. The enclosure further comprises the at least one sidewall between the open mouth and closed end constricted by the at least one neck ligature against the outdrive engine proximate a neck of the outdrive engine, thereby reducing the volume contained inside the enclosure in the deployed configuration. The neck of the outdrive engine is defined by a smallest circumference around the outdrive engine that passes between a cavitation plate and a cowling above the cavitation plate. Lastly, fluid communication between outside of the enclosure and inside of the enclosure while the enclosure is in the deployed configuration is inhibited sufficient that a veliger extinction capacity within the enclosure outpaces a rate of veliger introduction to the outdrive engine while the enclosure is in the deployed configuration.

Particular embodiments may comprise one or more of the following features. The outdrive engine enclosure may further comprise at least one unidirectional valve embedded within at least one sidewall, each of the at least one unidirectional valve may have a flow direction and may be oriented such that the flow direction is leaving the enclosure. The at least one neck ligature may comprise two neck ligatures. At least one of the at least one neck ligature and/or the transom ligature comprises an elastic material. The at least one sidewall may comprise a top sidewall, a bottom sidewall, and/or two side sidewalls. Lastly, the outdrive engine enclosure may further comprise a transom section comprising the open mouth, the transom ligature, and/or a first portion of the at least one sidewall. The transom section may be coupled to a neck section along a first junction. The neck section may comprise the at least one neck ligature and/or a second portion of the at least one sidewall. A prop section may be coupled to the neck section along a second junction and/or comprising the closed end and a third portion of the at least one sidewall. Finally, the enclosure at the first junction may narrow along at least a first path and the enclosure at the second junction expands along at least a second path.

According to yet another aspect of the disclosure, a method for inhibiting the biofouling of an outdrive engine includes running the outdrive engine until an internal temperature of at least 130° F. is reached, pulling an outdrive engine enclosure over a distal end of the outdrive engine such that a skeg and a prop of the engine pass through an open mouth of the outdrive engine enclosure. The enclosure comprising at least one sidewall forming the open mouth and a closed end opposite the open mouth. The method further includes sliding the outdrive engine enclosure up along the outdrive engine until the open mouth is proximate a transom through which the engine is coupled and the prop is proximate the closed end. The method also includes coupling the enclosure to the transom by constricting a transom ligature coupled circumferentially about and proximate to the open mouth until the at least one sidewall proximate the open mouth is pressed against at least one of a transom mounting rim and a gimbal housing to form a transom seal that is substantially watertight, reducing a volume of water trapped inside the enclosure with the engine by constricting at least one neck ligature coupled circumferentially about the at least one sidewall between the open mouth and the closed end, thereby pressing the at least one sidewall against the outdrive engine proximate a neck of the outdrive engine and placing the enclosure into a deployed configuration. The neck of the outdrive engine is defined by a smallest circumference around the outdrive engine that passes between a cavitation plate and a cowling above the cavitation plate.

Particular embodiments may comprise one or more of the following features. Putting the outdrive engine enclosure into the deployed configuration may be accomplished within 10 minutes or less of the engine achieving the internal temperature of at least 130° F. The method may further include placing a veliger inhibitor inside each of at least one veliger inhibitor pocket before pulling the enclosure over the distal end of the engine. Each of the at least one veliger inhibitor pocket may be positioned on the inside of the enclosure and/or each veliger inhibitor may be one of a deoxygenator and a veliger poison. Additionally, the method may include placing a visual reminder to prevent accidental engagement of the prop while the prop is inside of the enclosure. Finally, the method may further comprise raising the outdrive engine into a raised position.

DETAILED DESCRIPTION

This disclosure, its aspects and implementations, are not limited to the specific material types, components, methods, or other examples disclosed herein. Many additional material types, components, methods, and procedures known in the art are contemplated for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any components, models, types, materials, versions, quantities, and/or the like as is known in the art for such systems and implementing components, consistent with the intended operation.

While this disclosure includes a number of embodiments in many different forms, there is shown in the drawings and will herein be described in detail particular embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the disclosed methods and systems, and is not intended to limit the broad aspect of the disclosed concepts to the embodiments illustrated.

Zebra mussels, and other invasive species such as quagga mussels, have rapidly become an expensive problem. Zebra mussels originated from the lakes of Russia and the Ukraine, and have since spread throughout the world. First noted in the Great Lakes in the 1980s, zebra mussels have quickly spread throughout many of the major lakes of the United States. Some estimate the annual cost of dealing with zebra mussels and repairing their damage to be in the hundreds of millions of dollars in the United States alone.

Removing zebra mussels from an entire lake is problematic. The impact of a poison on the ecosystem of an entire lake, as well as the effect of introducing a large mass of dead zebra mussels, is very difficult to predict. Also, the process of getting regulatory approval for large-scale treatment has been slow. In the meantime, boat owners are left to wage their own battle against biofouling from zebra mussels, quagga mussels, and other invasive species.

It is hard to overstate the negative impact zebra mussels have on the ecology, infrastructure, and property in infested bodies of water. Zebra mussels reproduce quickly; adult females can each produce up to a million eggs a year. The free-swimming microscopic larvae, called veligers, drift in the water before settling onto any hard surface available. With respect to boats, the biofouling is not limited to the exterior surfaces of the hull, engine, and other submerged elements. Veligers that are drawn into, or swim into, engine passages can settle in the cooling system where they can grow into adults, blocking internal screens, hoses, passages, strainers, etc. Such blockages can cause an engine to quickly overheat, and extraction and repair can be very expensive.

Performance advantages and lower cost have led to the popularity of sterndrive boats, also called I/O or inboard/outboard drive boats. The hallmark feature of a sterndrive boat is that the engine is onboard, and the rest of the propulsion system is outside of the boat, passing through the transom, with the flexible connection typically protected by a baffle or bellow device. Although most outdrives can be raised up, sometimes they are still partially in the water; furthermore, an outdrive in the raised position exposes the baffle to weather and UV damage, as well as damage from animals, birds or invasive insects and sharp objects. As such, outdrives are often left in the water when the boat is moored. In zebra mussel infested waters, such exposure can lead to degraded performance and even an inoperative cooling system. While the best way to avoid mussel problems is to remove the boat from the water and rinse it with hot water, this is not always a practical solution.

Traditional methods of preventing zebra mussel growth on drives in the water have relied on using special materials, or coating surfaces with waxy or soapy substances that prevent the veligers from bonding with the surface. However, these methods are problematic, as materials can degrade over time and can be difficult to replace; furthermore, an entire coolant system would have to be rebuilt with these materials in a traditional engine. The use of coatings can be effective, but it can be difficult to determine whether an application was sufficient before mussels have started growing. Also, the use of such substances is not feasible on the internal passages of an engine, such as the cooling system.

Contemplated herein is a system and method for preventing the biofouling of an outdrive. According to various embodiments, the system comprises an outdrive enclosure and may further comprise at least one veliger inhibitor. Advantageously, the outdrive enclosure may be used to isolate a heated outdrive from the body of water in which it rests. Specifically, embodiments of the outdrive enclosure isolate the outdrive and all entry points to the cooling system from the surrounding body of water. Such isolation is advantageous over traditional methods of preventing zebra mussel incursion, in that it allows for the use of water-based methods otherwise impractical or illegal to use in open water. Furthermore, the outdrive enclosure is easy to deploy, and may also serve to protect the outdrive from weather and UV damage. By enclosing the outdrive, only the veligers captured inside the enclosure need to be dealt with, rather than a steady current of veligers passing by an unprotected outdrive.

While the non-limiting embodiments discussed herein are directed for use with the outdrive of a sterndrive boat, these systems and methods may be adapted for use with other types of boat drives and engines known in the art. Furthermore, the following discussion will refer to zebra mussels, but should be understood to also apply to other invasive bivalves such as the quagga mussel, as well as other biofouling vectors such as barnacles and the like.

FIG. 1shows a perspective view of non-limiting example of an outdrive engine enclosure100. This particular embodiment is shown in a deployed configuration114, meaning it has been applied to the outdrive engine of a boat. As shown, the outdrive engine enclosure100comprises an open mouth104and a closed end102defined by and composed of one or more sidewalls110. The enclosure100further comprises a transom ligature106and at least one neck ligature108.

As previously mentioned,FIG. 1shows an outdrive engine enclosure100in a deployed configuration114. In the context of the present disclosure and the claims that follow, a deployed configuration114of an enclosure100is when the enclosure100has been applied to the engine in such a way that fluid communication between the exterior of the enclosure100and the interior of the enclosure100, if any, is small enough that the introduction of new veligers does not outpace the rate at which they are being exterminated within the enclosure100. Such a configuration may also be described as being “substantially watertight”.

According to various embodiments, the degree to which water flow is restricted depends upon the intended use environment. For example, embodiments intended for use on watercraft stored in turbulent water (e.g. ocean, large bodies of water exposed to high winds, etc.) may, out of necessity, comprise materials (e.g. sidewalls, ligatures, etc.) and construction that provides a greater attenuation of fluid communication than embodiments intended for use in calmer circumstances, where more porous materials/construction may be sufficient. However, all embodiments, when in the deployed configuration114in their intended use environment, may be described as substantially or sufficiently watertight.

FIG. 1depicts the enclosure100in a deployed configuration114while the engine is in a raised position124. According to various embodiments, the enclosure100may be used on an engine while it is in a raised or lowered position.

As shown inFIG. 1, the outdrive enclosure100may be shaped to conform to the profile of an outdrive engine. In some embodiments, the outdrive enclosure100may be sized and shaped to work with a range of popular outdrive shapes and sizes. In other embodiments, the outdrive enclosure100may be “bespoke”, sized to fit a particular outdrive close enough to reduce the enclosed volume yet loose enough that application is not difficult.

In some embodiments, the open mouth104may be sized such that the cavitation plate and the skeg of the engine can pass through the open mouth104at the same time. In many outdrive engines, this would represent the widest, and possibly most difficult, part of the engine to insert through an aperture such as the open mouth104. Sizing the outdrive enclosure for a specific outdrive may be advantageous, as an enclosure that is too large may result in trapped volumes of water, which may protect veligers from the inhibitor and allow them to later infest the outdrive.

If the outdrive enclosure100is allowed to move with the surrounding water currents, the jostling may compromise the transom seal112and allow veliger-infested water to enter the enclosure100and outdrive200. According to various embodiments, the outdrive engine enclosure100may employ a number of ligatures to secure the enclosure in place, as well as to minimize the volume of veliger-laden water trapped inside after installation.

In the context of the present description and the claims that follow, a ligature is an object used to tightly tie or bind part of the enclosure100to another object, such as the transom or the engine itself. Examples of ligatures include, but are not limited to, straps, belts, ropes, cables, elastics, and the like.

As shown inFIG. 1, an outdrive engine enclosure100may comprise two kinds of ligatures: a transom ligature106and at least on neck ligature108. In the context of the present description and the claims that follow, a transom ligature106is a ligature that is coupled to the one or more sidewalls110of the enclosure along or near the perimeter of the open mouth104. The transom ligature106is used to secure the open mouth104of the enclosure100to the engine or the boat transom to which the engine is coupled, creating a transom seal112that prevents the interior of the enclosure100, as well as the engine itself, from being overrun by veligers. In some embodiments, the transom ligature106is constrictably coupled to the sidewalls110, meaning it is coupled to the sidewalls110yet still able to constrict around the sidewalls110(until they are pinned against another structure such as the transom or the engine itself). In other embodiments, the transom ligature106may be functionally attached to the sidewalls110in such a way that the ligature106is coupled to the enclosure100while still being free to reduce the size of the enclosure100in a fashion other than constriction (e.g. wrapping, etc.).

In addition to a transom ligature106, some embodiments also include at least one neck ligature108. In the context of the present description and the claims that follow, a neck ligature108is a ligature that is coupled to the one or more sidewalls110of the enclosure100circumferentially, somewhere between the open mouth104and the closed end102. More specifically, according to various embodiments, neck ligatures108are positioned with respect to the sidewalls110such that when the enclosure100is in a deployed configuration114, the neck ligatures108are proximate the neck of the engine. See, for example, the neck214of the outdrive engine200ofFIG. 2. Neck ligatures may be used to reduce the internal volume of the enclosure100after it has been placed over an outdrive engine, such as the engine200ofFIG. 2. For example, according to various embodiments, a neck ligature108may press the one or more sidewalls110against the body of the engine.

According to various embodiments, and as shown inFIG. 2, the neck214of an outdrive engine200is defined by a smallest circumference216around the outdrive engine200that passes between a cavitation plate204and a cowling206above the cavitation plate204. The neck214often represents a narrowing in the profile of the engine200; a ligature applied near the neck214will be more secure and less likely to slip off due to jostling.

In the non-limiting example shown inFIG. 1, the neck ligatures108and the transom ligature106are all nylon straps118, each having a buckle120and constrictably coupled to the sidewalls110through a plurality of loops122.

Some embodiments may comprise one, two, three, four, or more straps118to secure the outdrive enclosure100to the outdrive200. The straps118and/or buckles120may be composed of any material known in the art for securing or cinching in an aquatic environment. In some embodiments, the straps118may be elastic in nature. Additionally, in some embodiments, the enclosure100may comprise some form of cushioning material on the inside, opposite the straps118, which may serve to protect the finish of the outdrive200from abrasion or damage.

FIG. 1shows the straps118being coupled to the outdrive enclosure100through a plurality of strap loops. According to various embodiments, the straps may be coupled to the body through loops, rings, apertures, or the like. In some embodiments, the straps may be incorporated into the enclosure body, such that they are at least partially within the walls of the body.

According to various embodiments, the transom seal112is the portion of the outdrive enclosure100that couples with or near the transom such that water is not able to freely flow between the inside of the deployed enclosure100and the outside. Typically, the area where the outdrive passes through the transom is protected by a flexible baffle, and the baffle interfaces with the transom such that there is a rim (e.g. transom mounting rim210ofFIG. 2) on the transom around the perimeter of the baffle. In some embodiments, the transom seal112couples with this rim. In other embodiments, the transom seal112may couple with some other part of the transom, baffle, or outdrive such that water is not able to flow into the deployed enclosure. For example, in one embodiment, the transom seal112may form on a gimbal housing212of the outdrive engine200.

The formation of the transom seal112is advantageous, as it limits the volume of water (and thus, number of veligers) that must be dealt with to protect the outdrive200from mussel infestation. By limiting the volume of water, the magnitude of required veliger inhibition is reduced. The role of inhibitors408will be discussed in greater detail below.

In some embodiments, the open mouth104may be watertight. In other embodiments, the open mouth104may allow only a small amount of water flow after the transom seal112has been formed, so long as it does not outpace whatever method of veliger inhibition is being used within the enclosure100. In some embodiments, the open mouth104may comprise a material conducive to forming a seal of sufficient strength, such as a rubber or foam rubber material.

In the non-limiting example shown inFIG. 1, the transom ligature106comprises a nylon strap118and buckle120. Other embodiments may use an elastic strap, a ratcheting buckle, and/or any other securing methods known in the art. In one embodiment, the transom seal112may comprise a combination of rubberized seal and a series of magnets that may couple with a series of magnets embedded or coupled to the transom. The use of magnets may be advantageous, as they may help ensure consistent positioning of the open mouth104to form the transom seal112(e.g. if all the magnets are aligned then the seal is uniform, etc.). In other embodiments, the open mouth104may be releasably coupled to the transom or proximate to the transom through various means, including but not limited to, magnets, adhesives, suction cups, clips, snaps, and/or anchors.

In some embodiments of the outdrive engine enclosure100, the enclosure100may further comprise one or more transom aperture covers. In the context of the present description and the claims that follow, a transom aperture may refer to any opening providing fluid communication between the surrounding body of water and the internal pathways of the boat or engine, such as a cooling intake or the exhaust system. According to various embodiments, when the outdrive enclosure100is fully deployed, a transom aperture cover is coupled to the transom and prevents or significantly reduces (e.g. reduced such that a veliger inhibitor can neutralize any incoming veligers, etc.) the flow of water through one or more transom apertures.

In some embodiments, a transom aperture cover may releasably couple with the structure proximate the one or more transom apertures through a variety of means, including but not limited to the means discussed above with respect to the releasable coupling of the open mouth104to the transom. In other embodiments, a transom aperture cover may be pressed against one or more transom apertures. For example, the transom aperture cover may comprise a rigid or semi-rigid biasing element, such that the outdrive enclosure100may be deployed while the outdrive200is in a raised position124, and then the covered outdrive is lowered to the down position, the transom aperture cover is pressed against the one or more transom apertures by the biasing element trapped between the outdrive200and the transom105, preventing the flow of water without damaging the boat. As an option, a transom aperture cover may be composed of a rubber or elastomer material, to facilitate the creation of a seal.

The sidewalls110of the outdrive enclosure100may be composed of any water-tight material known in the art, including but not limited to plastic, resin, fabric, coated fabric, fiberglass, composite materials, rubber, and/or any other material known in the art. In some embodiments, the outdrive enclosure100may be composed, or partially composed, of a rigid material, providing greater mechanical protection to the outdrive200. In other embodiments, including the non-limiting examples shown inFIG. 1, the outdrive enclosure100may be composed of a flexible material. In some embodiments, the enclosure may be flexible enough to fold for storage. Furthermore, in some embodiments, the outdrive enclosure100may be composed of a material able to withstand various methods of zebra mussel decontamination, including but not limited to, application of hot (e.g. 140° F.) water, freezing, and/or chemical rinses (e.g. chlorine solution, etc.).

Some embodiments of the outdrive enclosure may be composed of a PVC coated fabric116, such as a lightweight polyester fabric, which may provide strength and durability. As an option, the coating may be both UV resistant as well as inhibit the growth of mildew. In some embodiments, the PVC coating may be on the outside of the enclosure100. As a specific example, the outdrive enclosure100may be composed of PVC coated polyester116having a weight of 18 oz. per square yard. The use of a PVC coated fabric116is advantageous, as punctures may be easily repaired with conventional PVC patch kits.

FIG. 1shows an outdrive enclosure100deployed on a boat that is on land. The use of an outdrive enclosure100on a boat in dry storage may be advantageous, as the enclosure100may protect sensitive parts, including but not limited to the baffle, from weather damage, UV damage, invasion of insects, and animals. However, it should be understood that the outdrive enclosure100is also meant to be used on an outdrive200of a boat moored in zebra mussel infested water.

FIG. 2shows a side view of a non-limiting example of an outdrive engine200comprising a skeg202, a cavitation plate204, a cowling206above the cavitation plate204, a prop208, a transom mounting rim210, a gimbal housing212, and a neck214.

As shown inFIG. 2, and as previously discussed, the neck214of an outdrive engine200is defined by a smallest circumference216around the outdrive engine200that passes between a cavitation plate204and a cowling206above the cavitation plate204. The neck214often represents a narrowing in the profile of the engine200; a ligature applied near the neck214will be more secure and less likely to slip off due to jostling.

In some embodiments, the outdrive engine enclosure100may be constructed from a single piece of material. In other embodiments, the outdrive engine enclosure100may be constructed from multiple sidewalls. For example, the non-limiting embodiment shown inFIG. 1comprises four sidewalls.FIGS. 3-5show schematic views of a side sidewall300, a top sidewall400, and a bottom sidewall500. Other embodiments may make use of two, three, five, six, or more sidewalls110.

As shown, the outdrive enclosure100comprises one or more veliger inhibitor pockets406on the inside of the enclosure body. As shall be discussed in greater detail with respect to the method, the veligers inside the outdrive200may be killed by raising the temperature of the engine200before deploying the outdrive enclosure100. However, as the enclosure100may be deployed while the outdrive200is in the water, the deployed enclosure100likely includes water that may contain veligers unharmed by the internal temperature of the engine200. The inhibitor pockets406hold one or more means for inhibiting the veligers from infesting the engine200after the enclosure100is deployed. Such inhibition may include preventing growth, or even killing the veligers. Because the outdrive enclosure100limits the volume of water that needs to be treated, inhibition means, methods, and materials normally too weak to be effective may be of use, and traditional methods may be employed in a greatly reduced capacity, as will be discussed.

In some embodiments, the inhibitor pockets406may be composed of the same material as the enclosure sidewalls110. In other embodiments, the inhibitor pockets406may be composed of a material that facilitates fluid communication between an inhibitor408stored in the pocket406and the rest of the enclosed water. For example, in one embodiment, the inhibitor pockets406may be composed of a nylon mesh. In some embodiments, the inhibitor pockets406may be closable (e.g. zipper, snap, hook and loop, button, drawstring, etc.) while in others the pockets406may be open.

Embodiments of the enclosure100may comprise one, two, three, four, five, or more inhibitor pockets406. The inhibitor pockets406may be uniform, or they may differ from each other to contain different types of inhibitors408. In some embodiments, the outside of the enclosure100may have a visual indication of the location of the internal inhibitor pockets406, to facilitate tactile verification of the presence of an inhibitor408(e.g. to make sure it wasn't forgotten, to determine if a dissolving inhibitor408is still present, etc.).

The outdrive enclosure100may further comprises at least one releasable vent502, as shown inFIG. 5. The releasable vent502allows the water inside the outdrive enclosure100to drain while facilitating the application and removal of the outdrive enclosure100(e.g. allowing water to drain when trying to lift the enclosure100up and around the engine200, etc.). In some embodiments, the vent502may be a valve or flap in the bottom surface of the enclosure. As a specific example, in one embodiment, the vent502may be beneath a strap, such as a neck ligature108, such that when the strap is cinched tight, the vent508is held closed, but when the neck ligature108is loosened, the vent502may freely open. In other embodiments, the vent502may be a one-way vent402(e.g. unidirectional vent402ofFIG. 4, etc.), designed to only allow water to exit the enclosure, but preventing any veliger tainted water from entering. In other embodiments, other vents502known in the art may be used, so long as they may be closed to prevent water from entering the enclosure100after the enclosure100has been deployed.

Other embodiments may employ one-way, or unidirectional valves402to facilitate application and subsequent compression of the enclosure100in an aquatic environment. The unidirectional valves402, which only allow water to flow through them in a single flow direction404, may be placed in one or more sidewalls110, such that water may escape from inside the enclosure100through the unidirectional valve402, but may not enter along the same path. The unidirectional valve402may be any one-way valve known in the art that is compatible with the other materials of the enclosure100.

According to various embodiments, the system for preventing the biofouling of an outdrive engine200may also include one or more veliger inhibitors408. A veliger inhibitor408is a device, substance, or compound which may prevent a veliger from growing large enough to damage a boat engine. In some embodiments, this is accomplished by killing the veliger, while in others it may be accomplished by depriving the veliger from a needed component for its growth. Some embodiments of the system make use of one type of veliger inhibitor408, while others may make use of multiple types or forms of inhibitors408. The inhibitors408only need be potent enough to inhibit the veligers contained in the enclosed water, as the transom seal112may prevent any additional veligers from entering after the enclosure100has been deployed.

One non-limiting example of a veliger inhibitor408is an organic infuser pouch, which may contain one or more organic compounds known to inhibit the growth of mussel larvae. Such compounds may include, but are not limited to, cayenne pepper, cinnamon, ginger, turmeric, wormwood, black walnut hulls, clove, garlic, ground heirloom cucumber seeds, ground papaya seeds, and raw pumpkin seeds. As a specific example, an infuser pouch may contain 2 tablespoons of cayenne pepper, and one teaspoon each of cinnamon, ginger, and turmeric. The infuser pouch may be composed of a paper or cloth material, similar to a tea bag, according to various embodiments. After deployment, the enclosed water is slowly infused with the organic compounds, inhibiting veliger infestation of the engine. This form of inhibitor408may be advantageous over conventional methods, as it is natural, biodegradable, and inexpensive to use on such a limited volume of water.

Since the veliger inhibitor408only needs to affect the small volume of water contained within the outdrive enclosure100, options otherwise unavailable to boaters in protecting their property may be used. For example, mussel poisons408b, such as the poisons derived from bacteria, are prohibited from use on a large scale. However, the small amount needed to treat the enclosure100may be granted regulatory permission sooner than the broad application to a lake. This applies to any of the other inhibitors408known in the art as well.

Another example of a veliger inhibitor408is a deoxygenator408a, which may deoxygenate the enclosed water to the point that it no longer is able to sustain the life of mussel larvae. In some embodiments, such a veliger inhibitor408may be reusable, releasing the captured oxygen upon the application of a stimulus such as heat. Yet another example of a veliger inhibitor408may function to heat the enclosed water to a temperature sufficient to kill the trapped veligers.

FIG. 6shows a schematic side view of a non-limiting example of an outdrive engine enclosure100. As shown, the enclosure100may be partitioned into three sections: a transom section600, a neck section602, and a prop section604. According to various embodiments, the transom section600includes the open mouth104, the transom ligature106, and a first portion610of the at least one sidewall. The transom section is coupled to the neck section602along the first junction606, and includes at least one neck ligature108and a second portion612of the at least one sidewall110. The prop section604is coupled to the neck section602along a second junction608and includes the closed end102and a third portion614of the at least one sidewall110.

According to various embodiments, the outdrive engine enclosure100may have a variety of shapes. For example, in one embodiment, the enclosure100may be uniform across the three sections, essentially forming a cylinder. In other embodiments, the shape of the enclosure may be modified to reduce the amount of wasted space inside the enclosure100. As the volume624of water trapped within the enclosure100after it has been put into the deployment configuration decreases, veliger inhibition efforts may become more effective and efficient.

For example, in the embodiment shown inFIG. 6, the enclosure100at the first junction606narrows along at least a first path616and the enclosure at the second junction608expands along at least a second path618. In this way, the irregular shape of an outdrive engine may be better fit by the enclosure, reducing wasted space. Such a reduction may serve to eliminate the veligers inside the enclosure100. Maintenance of such an elimination may be accomplished by reducing the waste volume such that a veliger extinction capacity620outpaces the rate of veliger introduction622to the enclosed outdrive engine.

Further contemplated in this disclosure is a method for employing the previously discussed enclosures100to prevent the biofouling of an outdrive200by zebra mussels. The following discussion is in the context of a single engine boat, but it should be clear to one skilled in the art that these systems and methods may be applied to boats having multiple engines.

FIG. 7shows a non-limiting example of a process flow for preventing biofoulding of an outdrive200. First, the outdrive engine200is run until an internal temperature sufficient to kill any larvae that have infiltrated the internal passages has been reached. See step700. According to some embodiments, this temperature may be at least 130° F., while in others it is over 140° F. As a specific example, an engine may be run at idle for 10 minutes to achieve a target temperature.

Next, the outdrive engine enclosure is pulled up over a distal end of the engine. See step702. This may be done while the outdrive is in a down position, or an up position, which may be more convenient depending on the particular shape and size of the outdrive. The outdrive enclosure needs to be in place before the internal temperature of the engine has dropped to the level where larvae may survive. In some embodiments, this may be between five and ten minutes after the engine is stopped.

As an option, before step702, one or more inhibitors may be placed in the inhibitor pockets on the inside of the outdrive enclosure. In some embodiments, the inhibitors may need to be replaced before each deployment of the outdrive enclosure, while in others, the inhibitors may last through multiple deployments and may only need replacement once depleted or inert.

The enclosure is then slid up along the outdrive engine200until the open mouth104is proximate the transom105and the prop is proximate the closed end102of the enclosure100. See step704.

Next, the enclosure100is coupled to the transom105by constricting a transom ligature106until a transom seal112is formed. See step706. Once the enclosure is over the outdrive and at least partially filled with water, the transom seal is secured to the transom (or, in some embodiments, secured to an object proximate the transom) such that water flow is discouraged. The heat of the engine will have killed any veligers on the inside.

Finally, the volume of trapped water is reduced by constricting the neck ligatures108. See step708. In some embodiments, a reminder may be placed over the boat throttle, to prevent anyone from accidentally starting the engine with the outdrive enclosure in place.

It will be understood that implementations are not limited to the specific components disclosed herein, as virtually any components consistent with the intended operation of a method and/or system implementation for preventing the biofouling of an outdrive may be utilized. Accordingly, for example, although particular outdrive enclosures and inhibitors may be disclosed, such components may comprise any shape, size, style, type, model, version, class, grade, measurement, concentration, material, weight, quantity, and/or the like consistent with the intended operation of a method and/or system implementation for preventing the biofouling of an outdrive may be used. In places where the description above refers to particular implementations of outdrive enclosures and veliger inhibitors, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these implementations may be applied to other enclosures and inhibitors.

Where the above examples, embodiments and implementations reference examples, it should be understood by those of ordinary skill in the art that other biofouling prevention systems, methods and examples could be intermixed or substituted with those provided. In places where the description above refers to particular embodiments of outdrive engine enclosures and customization methods, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these embodiments and implementations may be applied to other to biofouling prevention technologies as well. Accordingly, the disclosed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the disclosure and the knowledge of one of ordinary skill in the art.