WATERCRAFT WITH CLOSED LOOP COOLING

Abstract

A watercraft comprising a hull, a first attachment coupled to an exterior surface of the hull, a second attachment coupled to the exterior surface of the hull, and a closed-loop cooling system. The closed-loop cooling system includes a pump, a first channel at least partially formed by the first attachment, a second channel at least partially formed by the second attachment, the second channel in fluid communication with the first channel, and a coolant circulated through the first channel and the second channel by the pump.

Claims

1. A watercraft comprising: a hull; a first spray strip coupled to an exterior surface of the hull; a second spray strip coupled to the exterior surface of the hull; and a closed-loop cooling system including: a pump, a first channel at least partially formed by the first spray strip, a second channel at least partially formed by the second spray strip, the second channel in fluid communication with the first channel, and a coolant circulated through the first channel and the second channel by the pump.

2. The watercraft of claim 1, wherein the hull includes a keel, and the first spray strip is positioned to one side of the keel and the second spray strip is positioned to another side of the keel.

3. The watercraft of claim 1, wherein the hull defines a bow-stern length, and the first spray strip extends at least 50% of the bow-stern length.

4. The watercraft of claim 3, wherein the first spray strip extends at least 75% of the bow-stern length.

5. The watercraft of claim 1, wherein the closed-loop cooling system further includes a connection line extending between the first channel and the second channel.

6. The watercraft of claim 1, wherein the closed-loop cooling system further includes a first plurality of protrusions extending into the first channel and a second plurality of protrusions extending into the second channel.

7. The watercraft of claim 6, wherein the first plurality of protrusions extends from the hull and the second plurality of protrusions extend from the hull.

8. The watercraft of claim 1, wherein an inlet aperture is formed in the hull at a first end of the first spray strip and an outlet aperture is formed in the hull at a second end of the first spray strip.

9. The watercraft of claim 1, further including a skeg coupled to the exterior surface of the hull, and wherein the closed-loop cooling system further includes a skeg channel at least partially formed by the skeg; and wherein the coolant is circulated through the first channel, the second channel, and the skeg channel by the pump.

10. The watercraft of claim 9, wherein the closed-loop cooling system further includes a radiator coupled to the hull, and wherein the coolant is circulated through the first channel, the second channel, the skeg channel, and the radiator by the pump.

11. The watercraft of claim 1, further including an electric drive and a battery electrically coupled to the electric drive; wherein the closed-loop cooling system is configured to cool the electric drive, the battery, or a combination thereof.

12. The watercraft of claim 1, wherein the coolant includes ethylene glycol and deionized water.

13. A watercraft comprising: a hull; a skeg coupled to an exterior surface of the hull; and a closed-loop cooling system including: a pump, a first channel at least partially formed by the skeg, and a coolant circulated through the first channel by the pump.

14. The watercraft of claim 13, wherein the first channel extends between an inlet formed in the skeg and an outlet formed in the skeg.

15. The watercraft of claim 14, wherein the first channel is serpentine.

16. The watercraft of claim 14, further including a plurality of parallel channels extending between an upstream portion of the first channel and a downstream portion of the first channel.

17. The watercraft of claim 13, further including a spray strip coupled to an exterior surface of the hull, and wherein the closed-loop cooling system further includes a second channel at least partially formed by the spray strip; wherein the coolant is circulated through the first channel and the second channel by the pump.

18. The watercraft of claim 17, wherein the closed-loop cooling system further includes a radiator including a shell coupled to the bull; and wherein the coolant is circulated through the first channel, the second channel, and the radiator by the pump.

19. The watercraft of claim 13, further including an electric drive and a battery electrically coupled to the electric drive; wherein the closed-loop cooling system is configured to cool the electric drive, the battery, or a combination thereof.

20. The watercraft of claim 13, wherein the coolant includes ethylene glycol and deionized water.

21.-49. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] These and other features, aspects, and advantages of the present technology will become better understood with regards to the following drawings. The accompanying figures and examples are provided by way of illustration and not by way of limitation.

[0055] FIG. 1 is to view of a watercraft with a closed-loop cooling system.

[0056] FIG. 2 is a bottom perspective view of the watercraft of FIG. 1.

[0057] FIG. 3 is a top perspective view of a first radiator and a second radiator of the closed-loop cooling system of FIG. 1.

[0058] FIG. 4 is another top perspective view of the first radiator and the second radiator.

[0059] FIG. 5 is a partial perspective cross-sectional view of the watercraft of FIG. 1.

[0060] FIG. 6 is an enlarged perspective cross-sectional view of a radiator and a channel formed in a spray strip.

[0061] FIG. 7 is a perspective cross-sectional view of the watercraft of FIG. 1, illustrating a channel of the closed-loop cooling system formed in a spray strip.

[0062] FIG. 8 is an enlarged perspective cross-sectional view of the channel formed in the spray strip, illustrating a plurality of protrusions extending into the channel.

[0063] FIG. 9 is a cross-sectional view of the watercraft of FIG. 1, illustrating a connection line extending between a first channel in a first spray strip and a second channel in a second spray strip.

[0064] FIG. 10 is a cross-sectional view of a watercraft including a hull with two coolant channels, with each coolant channel formed by a groove in the hull and an attachment coupled to the hull.

[0065] FIG. 11 is a perspective view of one of the coolant channels of FIG. 10.

[0066] FIG. 12 is a bottom perspective view of a watercraft with a closed-loop cooling system.

[0067] FIG. 13 is an enlarged bottom perspective view of FIG. 12.

[0068] FIG. 14 is a top enlarged perspective view of the watercraft of FIG. 12.

[0069] FIG. 15 is a cross-sectional view of the watercraft of FIG. 12.

[0070] FIG. 16 is a cross-sectional view of a skeg attachment with cooling channels for a watercraft.

[0071] FIG. 17 is a cross-sectional view of a skeg attachment with a cooling channel for a watercraft.

[0072] FIG. 18 is a flow-chart of a method for charging a battery and circulating a closed-loop coolant while the watercraft is positioned out of the water.

[0073] Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

DETAILED DESCRIPTION

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0075] The terms comprise(s), include(s), having, has, can, contain(s), and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms a, an and the include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments comprising, consisting of and consisting essentially of, the embodiments or elements presented herein, whether explicitly set forth or not.

[0076] For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated.

[0077] The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term coupled is to be understood to mean physically, magnetically, chemically, fluidly, electrically, or otherwise coupled, connected or linked and does not exclude the presence of intermediate elements between the coupled elements absent specific contrary language.

[0078] As used herein, the term spray strip refers to a rail or strip of material coupled to the bottom of a watercraft, also known as strakes. Spray strips deflect the spray thrown up when the hull of the watercraft is moving through the water.

[0079] As used herein, the term skeg refers to a projection or fin on the bottom of a watercraft, also known as skeg or skag.

[0080] To facilitate the understanding of this disclosure, a number of marine terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present disclosure. Starboard refers to the right-hand, or driver's, side of the watercraft. Port refers to the left-hand, or passenger's, side of the watercraft. Bow refers to the front of the watercraft. Transom and stern refer to the rear of the watercraft. The starboard 2, port 4, bow 6, and stern 8 directions are illustrated in FIG. 1 for reference.

[0081] With reference to FIG. 1, a watercraft 10 includes a hull 14 that defines a center bow-stern axis 18. In some embodiments, the watercraft 10 is propelled through the water by a propeller that is rotationally driven by an electric drive. In some embodiments, the electric drive includes an electric motor (e.g., an induction motor, a synchronous motor, a brushless DC motor, a permanent magnet rotor, an interior permanent magnet motor, a surface permanent magnet motor, a reluctance motor, etc.) and a power converter (e.g., an inverter, a converter, etc.). In some embodiments, the watercraft includes a battery electrically coupled to the electric drive. The watercraft is steered through the water with adjustment of a rudder, for example, by an operator input (e.g., steering wheel).

[0082] With continued reference to FIG. 1, the watercraft 10 includes a closed-loop cooling system 22. In the illustrated embodiment, the closed-loop cooling system 22 includes a pump 26, a first channel 30, a second channel 34, a first radiator 38, and a second radiator 42. The closed-loop cooling system 22 is configured to cool the electric drive, the battery, or any other heat-generating component 24 on the watercraft 10. The heat-generating components 24 are cooled by a coolant, and the heated coolant is circulating through the channels 30, 34 and the radiators 38, 42 to expel thermal energy to the external water (e.g., the water in which the watercraft 10 floats) or air (e.g., when the watercraft 10 is positioned out of the water, for example, on a trailer or lift).

[0083] In the illustrated embodiment, the coolant is circulated through the heat-generating component 24, the first channel 30, the second channel 34, the heat-generating component 24, the first radiator 38, and the second radiator 42 by the pump 26. In the illustrated embodiment, the coolant is serially circulated through the first channel 30, then the second channel 34, then the first radiator 38, and then the second radiator 42with fluid flow represented by arrows in FIG. 1. In other words, the channels 30, 34 are fluidly coupled to the radiators 38, 42. In other embodiments, the channels are in one cooling circuit and the radiators are in a separate parallel cooling circuit. In some embodiments, the coolant includes a mixture of ethylene glycol and deionized water. Advantageously, the closed-loop cooling system 22 does not circulate external water.

[0084] With reference to FIG. 3, the hull 14 includes a plurality of longitudinal stiffeners 46 (e.g., spars) extending in a bow-stern direction (e.g., along the bow-stern axis 18). The hull 14 further includes transverse stiffeners 50 (e.g., ribs) extending in a starboard-port direction (e.g., orthogonal to the bow-stern axis 18). For example, the hull 14 includes a first transverse stiffener 50A and a second transverse stiffener 50B extending parallel to the first transverse stiffener 50A. The hull 14 further includes at least one skin panel 54 coupled to the longitudinal stiffeners 46, the transverse stiffeners 50, or both. The skin panel 54 defines an exterior surface 58 of the hull 14 and includes an interior surface 62 opposite the exterior surface 58. A distance between the exterior surface 58 and the interior surface 62 defines a skin panel thickness 66.

[0085] With reference to FIGS. 3-6, the hull 14 includes a keel 70 and the first radiator 38 is positioned to one side of the keel 70 (e.g., starboard side), and the second radiator 42 is positioned to another side of the keel 70 (e.g., port side). In other words, the bow-stern axis 18 is positioned between the first radiator 38 and the second radiator 42. The first radiator 38 is positioned between the first transverse stiffener 50A and the second transverse stiffener 50B. Likewise, the second radiator 42 is positioned between the first transverse stiffener 50A and the second transverse stiffener 50B. In the illustrated embodiment, the first radiator 38 and the second radiator 42 are positioned at the same longitudinal position along the bow-stern axis 18.

[0086] The first radiator 38 includes a first shell 74 and a first cavity 78 is at least partially defined by the first shell 74 and the hull 14. The pump 26 circulates the coolant through the first cavity 78. The first shell 74 includes a main wall portion 82 and a plurality of sidewalls 86 extending from the main wall portion 82. The first shell 74 defines an opening 90 opposite the main wall portion 82. In other words, the first shell 74 does not define an enclosed volume or cavity by itself. In the illustrated embodiment, the opening 90 of the first shell 74 is closed off by the interior surface 62 of the skin panel 54. As such, the interior surface 62 of the skin panel 54 defines a portion of the first cavity 78. Advantageously, the skin panel 54 forms a direct heat conduction path from the first cavity 78 to the external water or air through only the skin panel thickness 66. In other words, the distance between the cavity 78 and the external water is minimized.

[0087] Likewise, the second radiator 42 includes a second shell 94 and a second cavity 98 is at least partially defined by the second shell 94 and the hull 14. The pump 26 circulates coolant through the second cavity 98. In the illustrated embodiment, the second cavity 98 is downstream of the first cavity 78. The second shell 94 includes a main wall portion 102 and a plurality of sidewalls 106 extending from the main wall portion 102. The second shell 94 defines an opening 110 opposite the main wall portion 102. Description related to the structure of the first radiator 38 detailed herein may also apply to the second radiator 42, and vice versa. In some embodiments, the watercraft 10 includes any number of radiators forming coolant cavities in combination with the hull 14.

[0088] In the illustrated embodiment, the radiators 38, 42 are at least partially positioned beneath the longitudinal stiffeners 46. With reference to FIG. 4, the first shell 74 and the second shell 94 are positioned between the plurality of longitudinal stiffeners 46 and the skin panel 54. In the illustrated embodiment, each of the plurality of longitudinal stiffeners 46 includes a notch 114 that is configured to receive the shell 74, 94. In other words, the radiators 38,42 extend through the notches 114 of the longitudinal stiffeners 46.

[0089] With reference to FIG. 5, the first radiator 38 includes an inlet 118 and an outlet 122. Coolant is pumped through the first cavity 78 from the inlet 118 to the outlet 122. Likewise, the second radiator 42 includes an inlet 126 and an outlet 130. Coolant is pumped through the second cavity 98 from the inlet 126 to the outlet 130.

[0090] With reference to FIGS. 5 and 6, the first radiator 38 and the second radiator 42 include a plurality of baffles 134 that extend between the shells 74, 94 and the hull 14. In the illustrated embodiment, the baffles 134 extend between the main wall portion 82, 102 of the shell 74, 94 and the interior surface 62 of the skin panel 54. In some embodiments, the plurality of baffles 134 also serve as longitudinal stiffeners (similar to the longitudinal stiffeners 46). In some embodiments, the baffles 134 are aligned with the longitudinal stiffeners 46. With reference to FIG. 6, in the illustrated embodiment, each of the baffles 134 includes an aperture 138, and the baffles 134 are arranged such that the apertures 138 of adjacent baffles 134 are at opposite ends to create a serpentine fluid flow path for the coolant through the cavities 78, 98, although alternate flow patterns can also be utilized. As such, the baffles 134 advantageously provide improve heat transfer through the radiators 38, 42 and also improved structural stiffness of the hull 14.

[0091] With reference to FIG. 2, the watercraft 10 includes a first attachment 142 coupled to the exterior surface 58 of the hull 14, and a second attachment 146 coupled to the exterior surface 58 of the hull 14. In the illustrated embodiment, the first attachment 142 is positioned to one side of the keel 70 (e.g., port side) and the second attachment 146 is positioned to another side of the keel 70 (e.g. starboard side). In the illustrated embodiment, the first attachment 142 is a first spray strip, and the second attachment 146 is a second spray strip. In the illustrated embodiments, the spray strips have a triangular-shaped cross-section. In some embodiments, the watercraft 10 includes any number of spray strips. As detailed further herein, in some embodiments, the attachment is a radiator, a spray strip, a skeg, a plate, or any other suitable structure attachable to the hull.

[0092] With reference to FIGS. 1 and 2, the hull 14 defines a bow-stern length 150 along the bow-stern axis 18 and the first attachment 142 extends at least 50% of the bow-stern length 150. In some embodiments, the first attachment 142 extends at least 75% of the bow-stern length 150. In some embodiments, the second attachment 146 is the same length as the first attachment 142.

[0093] With reference to FIGS. 7 and 8, the first channel 30 of the closed-loop cooling system 22 is at least partially formed by the first attachment 142. Likewise, the second channel 34 of the closed-loop cooling system 22 is at least partially formed by the second attachment 146. In other words, coolant flow channels 30, 34 for the closed-loop cooling system 22 are integrated into the spray strips 142, 146 attached to the hull 14. As such, the first attachment 142 and the second attachment 146 provide a direct heat conduction path for heat exchange between the coolant and the external water or air. Advantageously, the cooling channels are integrated into spray strip structure that is in direct contact with the external water and added to structure (e.g., the spray strips) that are providing additional functionality (e.g., redirecting spray and generating additional lift) for the watercraft.

[0094] An inlet aperture 154 (shown positioned behind the second transverse stiffener 50B from the view of FIG. 3) is formed in the hull 14 at a stern end 158 of the first attachment 142, and an outlet aperture 162 (FIG. 9) is formed in the hull 14 at a bow end 166 of the first attachment 142. An inlet aperture 170 (FIG. 9) is formed in the hull 14 at a bow end 174 of the second attachment 146, and an outlet aperture 178 (shown positioned behind the second transverse stiffener 50B from the view of FIG. 3) is formed in the hull 14 at a stern end 182 of the second attachment 146. With reference to FIG. 9, the second channel 34 is in fluid communication with the first channel 30. In the illustrated embodiment, the closed-loop system 22 includes a connection line 186 extending between the first channel 30 and the second channel 34. Specifically, the connection line 186 extends between the outlet aperture 162 of the first attachment 142 and the inlet aperture 170 of the second attachment 146. As such, coolant flows in a bow direction through the first channel 30 and first attachment 142, and in a stern direction through the second channel 24 and second attachment 146.

[0095] With continued reference to FIGS. 7 and 8, a plurality of protrusions 190 extends into the first channel 30 and the second channel 34. The protrusions 190 are configured to disrupt the fluid flow through the channels 30, 34 to improve heat transfer. In other words, the protrusions 190 generate turbulent fluid flow through the channels 30, 34, which mixes the coolant and improves heat transfer from the coolant to the external water or air. In the illustrated embodiment, the protrusions 190 extend from the hull 14. In other embodiments, the protrusions extend from the attachments. In some embodiments, a first portion of the protrusions 194 are positioned with a first orientation and a second portion of the protrusions 198 are positioned with a second orientation, different than the first orientation. In the illustrated embodiment, the protrusions 194, 198 with different orientations alternate along the channel.

[0096] In operation, heat-generating components 24 (e.g., a battery, an electric motor, an inverter, etc.) are cooled by the coolant pumped and circulated through the closed-loop cooling system 22. Thermal energy in the coolant is then exchanged with the external water or air that watercraft 10 is floating in. In the illustrated embodiment, the coolant is cooled by flowing through the spray strips 142, 146 and the radiators 38, 42, each of which have a direct heat conduction path (e.g., a single layer of material) between the coolant flow and the external water.

[0097] In some embodiments, the closed-loop system includes a plurality of cooling circuits operating in parallel. For example, the coolant flowing through the radiators may be separate from coolant flowing through the spray strip channels. In some embodiments, the closed-loop cooling system includes radiators but no spray strip channels. In other embodiments, the closed-loop cooling system includes spray strip channels but no radiators.

[0098] With reference to FIGS. 10 and 11, a watercraft 210 is illustrated with a hull 214 having a first groove 218 and a second groove 222 formed in an exterior surface 226 of the hull 214. In some embodiments, the hull 214 is fiberglass. A first attachment 230 is coupled to the exterior surface 226 of the hull 214, and a second attachment 234 is coupled to the exterior surface 226 of the hull 214. In the illustrated embodiment, the first attachment 230 and the second attachment 234 are flat. With reference to FIG. 11, the hull 214 includes a first seat 238 that at least partially receives the first attachment 230. In the illustrated embodiment, an exterior surface 242 of the first attachment 230 is flush with the exterior surface 226 of the hull 214. In other words, the grooves 218, 22 are covered by the attachments 230, 234 such that the exterior surface 226 of the hull 214 appears smooth or continuous with the exterior surface of the attachments.

[0099] A first channel 246 (similar to the first channel 30) is at least partially defined by the first attachment 230 and the first groove 218. Likewise, a second channel 250 (similar to the second channel 34) is at least partially defined by the second attachment 234 and the second groove 222. Like the channels 30, 34 in the closed-loop cooling system 22, the channels 246, 250 are configured to circulate coolant in a closed-loop cooling system to directly transfer heat to the external water. As such, the attachments 230, 234 are similar to the attachments 142, 146, except the attachments 230, 234 are flat and flush mounted to the exterior surface of the hull, whereas the attachments 142, 146 are triangular-shaped and extend from the exterior surface of the hull.

[0100] With reference to FIG. 12, a watercraft 310 includes a hull 314 that defines a center bow-stern axis 318. In some embodiments, the watercraft 310 is propelled through the water by a propeller that is rotationally driven by an electric drive. In some embodiments, the electric drive includes an electric motor (e.g., an induction motor, a synchronous motor, a brushless DC motor, a permanent magnet rotor, an interior permanent magnet motor, a surface permanent magnet motor, a reluctance motor, etc.) and a power converter (e.g., an inverter, a converter, etc.). In some embodiments, the watercraft includes a battery electrically coupled to the electric drive. The watercraft is steered through the water with adjustment of a rudder, for example, by an operator input (e.g., steering wheel).

[0101] With reference to FIGS. 12-14, the watercraft 310 includes a closed-loop cooling system 322. In some embodiments, the closed-loop cooling system 322 includes a pump 326, and a channel at least partially formed by an attachment coupled to an exterior surface 330 of the hull 314, and a coolant circulated through the channel by the pump 326. In some embodiments, the attachment is radiator, a spray strip, a skeg, or any other suitable structure configured to attach to the hull 314.

[0102] In the illustrated embodiment, the watercraft 310 includes a first radiator 334 and a second radiator 338 coupled to the exterior surface 330 of the hull 314. In the illustrated embodiment, the watercraft 310 includes a first skeg 342 and a second skeg 346 coupled to the exterior surface 330 of the hull 314. Heat-generating components are cooled by the coolant and the heated coolant is circulated through the first radiator 334, the second radiator 338, the first skeg 342, the second skeg 346, or any combination thereof to expel thermal energy to the external water (e.g., the water in which the watercraft 310 floats) or air (e.g., when the watercraft 310 is positioned out of the water, for example, on a trailer or lift).

[0103] With reference to FIGS. 13-15, the first radiator 334 is coupled to the external surface 330 of the hull 314 with a first plurality of fasteners 350, and the second radiator 338 is coupled to the external surface 330 of the hull 314 with a second plurality of fasteners 354. The first radiator 334 includes a fluid inlet 358 formed in one of the first plurality of fasteners 350, and a fluid outlet 362 formed in another one of the first plurality of fasteners 350. In other words, the fluid inlet 358 and the fluid outlet 362 are also utilized to fasten or otherwise secure the first radiator 334 to the hull 314. The fluid inlet 358 extends through the hull 314 and the fluid outlet 362 extends through the hull 314. The second radiator 338 also includes a fluid inlet 366 formed in one of the second plurality of fasteners 354, and a fluid outlet 370 formed in another one of the second plurality of fasteners 354. Advantageously, incorporating fastening and fluid ports together reduces the number of hull penetrations and possible leak paths.

[0104] With reference to FIG. 15, the first radiator 334 includes a plurality of channels 374 formed in the first radiator 334. Each of the plurality of channels 374 is in fluid communication with the fluid inlet 358 and the fluid outlet 362. As disclosed here, the coolant is circulated through the fluid inlet 358, the channels 374, and the fluid outlet 362 by the pump 326. In some embodiments, the second radiator 338 is similar or identical to the first radiator 334. The hull 314 includes a groove 378 in the exterior surface 330 and the first radiator 334 is at least partially positioned within the groove 378. In the illustrated embodiment, the second radiator 338 is likewise at least partially positioned with a second groove 382 formed in the hull 314. In the illustrated embodiment, the hull 314 is formed of fiberglass and the radiators 334, 338 are formed of aluminum.

[0105] With reference to FIG. 16, a skeg 386 includes a first channel 390 at least partially formed by the skeg 386. As disclosed herein, the first channel 390 is part of the closed-loop cooling system 322 and the coolant is circulated through the first channel 390 by the pump 326. The first channel 390 extends between an inlet 394 formed in the skeg 386 and an outlet 398 formed in the skeg 386. In the illustrated embodiment, the skeg 386 further includes a plurality of parallel channels 402 extending between an upstream portion 406 of the first channel 390 and a downstream portion 410 of the first channel 390. Incorporating closed-loop cooling into the skeg advantageously adds additional functionality (e.g., cooling capacity) to structure already positioned on the hull for other purposes (e.g., improving stability).

[0106] With reference to FIG. 17, a skeg 414 includes a first channel 418 at least partially formed by the skeg 414. As disclosed herein, the first channel 418 is part of the closed-loop cooling system 322 and the coolant is circulated through the first channel 418 by the pump 326. The first channel 418 extends between an inlet 422 formed in the skeg 414 and an outlet 426 formed in the skeg 414. In the illustrated embodiment, the first channel 418 is a serpentine flow path.

[0107] In some embodiments, the closed-loop cooling system includes any combination of features disclosed herein including, but not limited to, an externally mounted radiator, an internal radiator shell, a spray strip flow channel, a skeg flow channel. In some embodiments, the features are fluidly connected in series or parallel. In some embodiments, the closed-loop cooling system includes more than one closed cooling circuit.

[0108] With reference to FIG. 18, a method 500 for charging a battery and circulating a closed-loop coolant while the watercraft is positioned out of the water. The method 500 includes (STEP 501) positioning a watercraft out of the water. In some embodiments, positioning the watercraft out of the water includes positioning the watercraft on a trailer or a lift.

[0109] The method 500 further includes (STEP 502) charging a battery positioning on the watercraft. In some embodiments, charging the batter (STEP 502) includes utilizing a power electronic device (e.g., a power converter, a power inverter, etc.), and wherein the power electronics device is cooled by the circulating coolant.

[0110] The method 500 further includes (STEP 503) circulating a coolant in a closed-loop cooling system during the charging (STEP 502). In other words, the coolant is circulated while the battery is being charged and the watercraft is out of the water. In some embodiments, coolant passes through at least one attachment (e.g., a spray strip, a skeg, a radiator, a plate, etc.) coupled to an exterior of the hull. In some embodiments, the attachment exchanges heat with the surrounding air. In some embodiments, the method 500 further includes positioning the watercraft in water and propelling the watercraft through the water with the battery after charging the battery.

[0111] In the illustrated embodiment, the watercraft 10, 310 is a boat. In other embodiments, the watercraft is a fishing boat, a dingy boat, a deck boat, a bowrider boat, a catamaran boat, a cuddy cabin boat, a center console boat, a houseboat, a trawler boat, a cruiser boat, a game boat, a yacht, a personal watercraft boat, a water scooter, a jet-ski, a runabout boat, a jet boat, a wakeboard, a ski boat, a life boat, a pontoon boat, or any suitable motor boat, vessel, craft, or ship.

[0112] Although an example is illustrated with respect to an all-electric watercraft, the closed loop cooling system described herein can also be used in a conventional motorboat application (e.g., with a gasoline or diesel-powered engine), where the cooling system is configured to cool the engine or other heat-generating components.

[0113] Various features and advantages are set forth in the following claims.