Catamaran Drone

Abstract

A drone catamaran having both length and beam is provided for carrying a platform. The catamaran includes a hull, a bridge, a pair of rails, a pair of pontoons, a waterproof package, a seat, and first and second pairs of elbow flanges. The hull is composed of an open plurality of ribs disposed along the length that extend below and across the beam. The bridge supports the platform and comprises a plurality of struts disposed along the length. Each strut extends laterally beyond the beam. The pair of rails connects to corresponding port and starboard ends of the struts. The pontoons provide buoyancy. Each pontoon affixes to a corresponding rail. The waterproof contains control, guidance and propulsion equipment. The seat supports the package, and comprises a plurality of slats distributed along the length. The first pair of flanges affixes to the bridge and in particular the struts. The second pair of flanges supports the seat. The struts, ribs, rails, flanges and slats are composed non-corrosive metal.

Claims

1. A drone catamaran for carrying a platform, said catamaran having both length and beam and comprising: a hull composed of an open plurality of ribs disposed along the length that extend below and across the beam; a bridge for supporting the platform, said bridge comprising a plurality of struts disposed along the length, each strut extending laterally beyond the beam; a pair of rails for connecting to corresponding port and starboard ends of said struts; a pair of pontoons for providing buoyancy, each pontoon affixing to a corresponding rail; a waterproof package for containing control, guidance and propulsion equipment; a seat to support said package; a first pair of elbow flanges for affixing to said bridge; and a second pair of elbow flanges for supporting said seat.

2. The catamaran according to claim 1, wherein said seat is composed of a plurality of slats distributed along the length.

3. The catamaran according to claim 2, wherein said struts, ribs, rails, flanges and slats are composed non-corrosive metal.

4. The catamaran according to claim 3, wherein said metal is aluminum alloy.

5. The catamaran according to claim 1, wherein said struts connect to said first flanges by nuts and bolts.

6. The catamaran according to claim 1, wherein said struts connect to said rails by nuts and bolts.

7. The catamaran according to claim 1, wherein said ribs connect to said first and second flanges by nuts and bolts.

8. The catamaran according to claim 2, wherein said slats connect to said second flanges by nuts and bolts.

9. The catamaran according to claim 1, wherein said propulsion includes a motor within said package that powers an external impeller.

10. The catamaran according to claim 1, wherein said guidance includes receiver communication.

11. The catamaran according to claim 1, wherein said guidance is autonomous.

12. The catamaran according to claim 1, further comprising: a center elbow flange disposed midway across said ribs and below said seat; and a ballast canister disposed onto said center elbow.

13. The catamaran according to claim 1, further including tabs disposed along select ribs of said plurality of ribs for maneuver.

14. The catamaran according to claim 1, further including cross-rods for connecting between said struts.

15. The catamaran according to claim 1, further including cross-rods for connecting between said ribs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] These and various other features and aspects of various exemplary embodiments will be readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which like or similar numbers are used throughout, and in which:

[0007] FIGS. 1A and 1B are elevation and perspective views of a low draft catamaran; and

[0008] FIGS. 2A and 2B are elevation and perspective views of a high stability catamaran.

DETAILED DESCRIPTION

[0009] In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and logical, mechanical, and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

[0010] The disclosure generally employs quantity units with the following abbreviations: length in meters (m) or feet (ft), mass in grams (g) or pounds-mass (lb.sub.m), time in seconds (s), angles in degrees () and force in newtons (N) or pounds-force (lb.sub.f). Supplemental measures can be derived from these, such as density in grams-per-cubic-centimeters (g/cm.sup.3), moment of inertia in kilogram-square-meters (kg-m.sup.2) and the like.

[0011] Historically, the U.S. Navy has used traditional hull vessels as target assets for testing purposes. Traditional in this case refers to a watertight hull design that penetrates from above the waterline to some depth (draft) below the waterline. These vessels may be modified to accept a remote control kit (human operated) or an autonomy kit (algorithmically controlled). The autonomy kits are typically owned by private companies and the cost of these kits is high. Moreover, the traditional vessels can be expensive to repair or replace when severely damaged.

[0012] The primary issue with these vehicles is cost, many of which cost over $200 k each. Under the naval doctrine for sailors to train as they fight, testing defense against a FAC/FIAC swarm requires five to ten of these vehicles for each live-fire event. In other words, the cost to adequately train Navy crews against this threat is prohibitively high.

[0013] Alternatively, a commercial off-the-shelf (CoTS) traditional boat design for test and evaluation restricts the U.S. Navy to an external supply chain, which introduce shortages and delays during production expansion. The exemplary design is readily scalable and can be manufactured by any competent machine shop, and then is simply bolted together. No welding is required in the structure itself.

[0014] FIGS. 1A and 1B show respective elevation and isometric views 100 of an exemplary first catamaran 110 with low draft, as depicted from the bow looking aft. A central hull 120 includes a platform that comprise upper and lower pairs of elbow flanges 130 connected to each other by underslung ribs 140 distributed along the length that extend across the beam (between port and starboard), and slats 150 across the lower flanges 130. The ribs 140 are separate and open, such that the volume under the upper flanges 130 is flooded.

[0015] A waterproof operations package 160 (shown as a metal box) is supported on the slats 150 that form a seat. The package 160 includes the control and propulsion systems for the catamaran 110, as well as communication and/or autonomous guidance equipment. An electric three-bladed propulsive impeller 165 is suspended underneath the package 160 and within the ribs 140. The impeller 165 can be powered by an internal motor controlled by the package 160, both for thrust generation and direction. The package 160 can be configured for autonomous operation or alternatively remote control via radio receiver. Alternative appropriate propulsion mechanisms can be used to substitute the impeller 165. At least one rudder (not shown) can optionally be installed but otherwise unnecessary.

[0016] A bridge 170 comprises lateral box struts 180 that extend both port and starboard from the keel beyond the beam's extent. The struts 180 attach at their ends to a pair of longitudinal rails 185. The struts 180 are distributed to openly span along the length. No skin is necessary either between the struts 180 or the ribs 140. The upper flanges 130 suspend from the box struts 180. A float pontoon 190 hangs from each rail 185 to provide buoyancy. For a typical configuration, the pontoons 190 can be approximately eight feet in length and separated by about ten feet, although this can be scaled larger or smaller as designed, such as an order of magnitude in either direction. Such pontoons 190 can be obtained from CoTS suppliers.

[0017] FIGS. 2A and 2B show respective elevation and isometric views 200 of an exemplary second catamaran 210 for high stability. A central hull 220 includes a platform that comprise upper and lower pairs of elbow flange 130 connected to each other by underslung ribs 140 across the beam, and slats 150 across the lower struts 130, similar to the low draft hull 120.

[0018] The hull 220 includes a third elbow flange 230 along the midline keel below the slats 150 and between the flanges 130 onto which ribs 240 connect. The flange 230 supports a ballast canister 250 to improve roll stability. A set of tabs 260 provide additional yaw stability when intended for trim, and or thrust vectoring to execute more aggressive maneuvers. In this configuration, the catamaran 210 is about 10 feet wide and about 8 feet long, with a draft of about 5 feet, due to the keel stabilization mechanism. In the embodiments shown, the plurality of struts 180 and ribs 140 and 240 is three, but this is configuration is exemplary and not limiting.

[0019] Similar to the low draft catamaran 110, the payload package 160 is supported on the slats 150. The propulsive impeller 165 is suspended from below the package 160 and within the ribs 140. The bridge 170 comprises box struts 180 with a pair of rails 185 at the end. The upper flanges 130 suspend from the box struts 180. Float pontoons 190 hang from the rails 185.

[0020] The bridge 170 can support a commercially available flat-bottom jon boat bolted thereon. The flanges 130, ribs 140, slats 150, struts 180 and rails 185 are preferably composed of non-corrosive metal, such as stainless steel or aluminium alloy. The pontoons 190 can be metal or plastic, depending on function. For subscale surface vehicles, capped polyvinyl-chloride (PVC) pipes can be used to produce the pontoons 190. The impeller 165 can be pivoted to maneuver the catamaran 110 or 210, and the number of such impellers 165 can be increased for increased speed.

[0021] Connections between the ribs 140 and the flanges 130 and the slats 150, as well as struts 180 and rails 185 can be provided by nuts and bolts, or by riveting, as preferred. Cross-rods can be attached between the ribs 140 and struts 180 for additional sheer and twist resistance. The designs for the catamarans 110 and 210 are similar with the primary difference of the respective hulls 120 and 220.

[0022] A 15-foot jon boat was bolted topside onto the bridge 170 of a prototype example of the catamaran 110 or 210 in order to simulate a FAC/FIAC. A CoTS autonomony kit in the package 160 and impeller 165 was integrated onto the hull 120 or 220 to provide motion control. A live-fire 30 mm gun engaged the catamaran 110 or 210 with the jon boat, demonstrating survivability and usability post-exercise. Typically, the catamaran 110 or 210 or any platform attached onto the bridge 170 would be unmanned under operation, although personnel can be aboard during water transport, as needed.

[0023] The utility of such the exemplary design enables firing ranges to test new weapons and/or train crews without concern over depleting the Navy reserve of traditional high-cost autonomous vessels. Additionally, due to the design of the catamaran 110 or 210, most of the structure is submerged underwater, thereby protecting the hull 120 or 220 from damage; any number of structures can be bolted to the bridge 170 as the intended target. As an example of cost scale, the proposed structure costs $20 k-$40 k (current dollars), while traditional vehicles cost well over $200 k.

[0024] Both exemplary embodiments of the catamaran 110 and 210 as well as similar variations therefrom are comparatively easy to construct. Such low-cost vessel that can use a variety of CoTS bolt-on propulsion mechanism and a CoTS autonomy kit within or extending from the package 160. As such, cost should be about $20 k-$40 k each, depending on auxiliary equipment and frame scale.

[0025] The frame for the bridge 170 and the hull 120 or 220 is composed of a non-corrosive metal, preferably aluminum, 5052 and 6061. The flanges 130, ribs 140, slats 150, struts 180 and rails 185 include holes drilled along their lengths so as to permit bolting together of the hull 120 or 220, and the bridge 170, thereby rendering welding unnecessary. A number of mount points along the frame exist for bolting various components to the catamaran 110 or 210. Both designs enable a rigid framework using a 500 lb.sub.m keel weight for stability that has shown good seaworthiness.

[0026] Finite Element Analysis (FEA) has been employed with these designs with 5-foot waves at a 5-second period, which represents an intense sea state. Actual vehicle tests at sea state three have been demonstrated. Other materials conducive to the maritime environment could be used as well (stainless steel for example). However, further FEA would need to be worked in order to guarantee no additional structural component would be needed.

[0027] A minimum number of distinct components is required to bolt the vehicle together. This is intentional, and contributes to the low-cost and scalability of the design. For the high stability design, there are only nine distinct machined pieces of aluminum/components. There are three bolt sizes used over the entire design, with two different thread pitches. The point here is that mass producing these components will drive the cost of the vehicles down considerably, even compared to the unit costs quoted in this disclosure.

[0028] Two exemplary designs of the vessel platform exist: a low draft catamaran 110 and high stability catamaran 210, both of which comprise of simple materials: aluminum box-beam, angle, and plate bent into shape. A watertight box for the package 160 is used to house the motor, autonomy kit, and batteries, although other means of enclosing these components is possible.

[0029] Either catamaran 110 or 210 can also be modified to a trimaran design, whereby a large pontoon float is located along the hull centerline and two enclosures, symmetrically flanking that center pontoon, are used for propulsion, control, etc. The catamarans 110 and 210 can employ any number of bolt-on autonomy kits, such as ArduPilot or PX4. This is intentional. The vessel is specifically designed to be scalable for testing, and as such must be capable of using a wide array of components.

[0030] The design for either catamaran 110 or 210 is scalable. If a larger vessel is required, more structural components can be bolted together, the width increased (by increasing the length of the aluminum box-beams) for better stability, the length increased by merely bolting additional components together longitudinally along the keel. Buoyancy can enhanced by adding pontoons 190 onto the bridge 170. The bolt-together design also facilitates a reduced storage footprint: the bridge 170 and hull 120 or 220 reduce to stacks of structural tubing.

[0031] A similar observation can be applied for the system mass, which is far less than a traditional rigid hull boat design. From a maintenance perspective, so long as materials are used that can survive in an aqueous medium (whether fresh or sea), the maintenance of these catamarans 110 and 210 is essentially negligible. Buoyancy can also be modified to accept various add-on payloads. The design can use PVC pipes (in various sizes) or CoTS pontoons 190, further enabling customization of the vessel's draft. Multiple mount points for these buoyancy generators can be used. Any number of physical characteristics-visual or radar/electromagnetic-can be bolted to the structure to emulate various targets desired for testing.

[0032] While pontoon boats are certainly not new, the rib vessel design does appear to be novel. Given the U.S. Navy's long-standing practice of target practice and fire exercise, such a cost-saving development represents a long-standing need. The design itself directly influences the cost of the vessel, which has many advantages as previously mentioned, including maintainability, scalability, seaworthiness, and survivability during live-fire test events. However, given the bolt together design, even if a component is damaged, that item can be quickly removed and replaced. This differs significantly from a traditional rigid hull boat, which can either sink or require extensive hull repairs that can exceed the value of the boat itself.

[0033] Additionally, the vehicle proposed here enables a new target type to be easily assembled and quickly tested: one simply attaches the intended target to this exemplary catamaran 110 or 210. Attributes, such as test vehicle speed and maneuverability, simply scale with the bolted on propulsion system the operator prefers to install.

[0034] The vessel is intrinsically scalable by adding larger pontoons, increasing the vessel width or length, etc, which increases utility for emulating many different types of targets. Frame components can also be longer and wider, or shorter and narrower, depending on availability of such structural components. Additionally, PVC pipe can be used for flotation instead of CoTS pontoons 190. This can become a consideration in the event that commercially available pontoons become scarce. Also, such an exemplary vessel can be modified into a trimaran design for high-speed operation.

[0035] The market for low-cost, autonomous vessels may be possible, for personal, foreign government, and corporate use. Maritime vessels typically are quite costly due to manufacturing techniques, which exemplary embodiments overcome. Bathymetry, surveying and ecological monitoring constitute investigative endeavors in which exemplary embodiments could be utilized.

[0036] While certain features of the embodiments of the invention have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.