US3483838A

US3483838A - Non-broaching beach cargo ship

Info

Publication number: US3483838A
Application number: US707845A
Authority: US
Inventors: Eric Rath
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-02-23
Filing date: 1968-02-23
Publication date: 1969-12-16
Anticipated expiration: 1986-12-16

Description

E. RATH 4 Sheets-Sheet l ATTORNEY Dec. 16, 1959 NoN-BROACHING BEACH CARGO SHIP Filed Feb. 23, 1968 Dec. 16, 1969 E. RATH NON-BROACHING BEACH CARGO SHIP 4 Sheets-Sheet 2 FiledFeb. 23, 1968 INVENTOR EW/C HA TH IIIIIIIIIIIII I;

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ATTO?? NEY Dec. i6, B969 E. RATH NON-BROACHING BEACH CARGO SHIP 4 Sheets-Sheet 3 Filed Feb. 25, 1968 INVENTOR EHIC H 7H BY ATTORNEY Dec. 16, 1969 E. RATH NoN-BROACHING BEACH CARGO SHIP 4 Sheets-Sheet 4 Filed Feb. 23, 1968 INVENTOR ERIC @i ATTORNEY United States Patent 3,483,838 NON-BROACHING BEACH CARGO SHIP Eric Rath, 17010 Sunset Blvd., Pacific Palisades, Calif. 90272 Filed Feb. 23, 1968, Ser. No. 707,845 Int. Cl. B63h 5/08; B63b 27/14, 1/04 US. Cl. 114-60 13 Claims ABSTRACT 0F THE DISCLOSURE A vessel including a hull particularly adapted for stern loading and unloading and means permitting transfer of cargo at sea; having plural retractable propulsion means orientable about a 360 axis of rotation to afford accurate maneuvering and stability in the surf; and having an unusual stem transom permitting direct loading of cargo onto a beach while compensating for littoral currents which subject conventional landing craft hulls to broaching, and oatation ramp to connect the transom with the beach.

Prior art cargo craft hulls, if designed for beaching by impact generally have been too slow to afford elcient, rapid, open-sea travel due to the specially shaped bottom to accommodate the beach gradient. Ocean going hulls of the 285' class, for example, generally have required special port and pier facilities, must be closely scheduled as to arrival, unloading and loading. lf proper port facilities are unavailable, lighters (of a relatively small capacity) must be used and extensive damage and pilferage occurs due to excessive cargo handling.

A primary object of the present invention is to provide a novel hull which permits direct loading and unloading of cargo onto remote, undeveloped beaches without beaching of the hull or broaching of the vessel and with a maximum efficiency.

Another object of the invention in conformance with that set forth is to provide a novel, extendable ramp, stored in the stern of the ships hull and floated out of the ship to the beach.

A further object of the invention is to provide a novel propulsion system for a hull which facilitates holding in the surf and/ or providing a safe transfer system of cargo from large steamer to shore via a hull capable of keeping a position in deep sea and rough weather.

And a still further object of the present invention is to provide a novel hull including a novel bow section facilitating at-sea transfer of cargo.

These, together with other and more specific `objects and advantages of the invention, will become apparent from a consideration of the following specification when considered with the accompanying drawing forming a part thereof, in which:

FIG. l is a fragmentary perspective view of a portion of a beach, essentially diagrammatic, and illustrating the general character of currents encountered when beaching a vessel;

FIG. 2 is a side elevational view of a hull incorporating the invention, showing in phantom lines a portion of an alternative superstructure, and the manner in which a displaceable bow portion is used to facilitate at-sea cargo transfer;

FIG. 3 is a bottom plan view of FIG. 2;

FIG. 4 is a vertical section taken substantially on the plane of line 4--4 of FIG. 2;

FIG. 5 is a vertical section taken substantially on the plane of line 5 5 of FIG. 2;

FIG. 6 is an enlarged, fragmentary elevational view of the hull stern, with portions broken away and showing details of a floodable well in which the extendable ramp is stored;

ICC

FIG. 7 is a top plan view of FIG. 6;

IG. 8 is a further enlarged fragmentary side elevational view showing details of a ramp support foot on the ramp;

FIG. 9 is a view similar to FIG. 8, showing the support foot in a stored position to permit storing of the ramp in the floodable well of the hull;

FIG. l0 is a vertical section taken on the plane of line 10-10 of FIG. 8;

FIG. 11 is a view similar to FIG 8 and showing how the support foot can assist in dislodging the ramp and/ or hull off a beach;

FIG. l2 is a fragmentary perspective View `of a hull portion showing one of the auxiliary retractable propulsion units; and

FIG. 13 is a vertical section generally at the vertical axis of propulsion unit of FIG. l2.

Before referring to the drawing in detail, the following factors should be kept in mind:

(l) Although individual troops can be readily transported, i.e. by air for example, the logistic problems with respect to equipment and supplies are extremely complex;

(2) Many remote areas seldom, if ever, have adequate dock and port facilities;

(3) Although large, fast and readily maneuverable ocean going vessels can substantially assist in overcoming the logistic problems of supply, none of these ocean going craft are designed to accommodate a variety of cargo including personnel, unitized cargo including both dry and refrigerated fresh foodstuffs, trailers, lowboys, tanks, cranes, personnel carriers, palletized cargo, etc., for direct landing on a beach, as well as afford landing areas for helicopters, for example;

(4) Further, ships generally designated as LST (Land Ship Tank) although designed for land cargo and personnel on a beach, are limited in speed and personnel accommodations and are generally subject to littoral current broaching forces.

The vessel and hull to be subsequently described cornprises essentially a powered :barge of a large capacity, i.e, 285 foot class, has a hull and keel configuration lending itself to eicient high speed travel, is capable of accurate maneuvers close to shore and at low speeds, can serve as a fuel tender for conventional submarines and/ or other type water craft, by accomplishing sensitive astern maneuvers in open sea, bridges over near-shore currents which tend to broach a conventional ship, can handle diversified cargo under substantially all beach and port conditions, and reduces cargo loading and unloading time to a minimum While providing increased stability under normally adverse conditions.

Dual-purpose ships for deep sea transportation and over-the-beach discharge face the problem of the beach currents to hold themselves in position 4while handling cargo. Since anchoring becomes impossible in the shallow water, the conventional vessel must beach itself by impact on the beach bottom. This stranding has severe damaging effects on the ship structure and bottom, but has in the past been the only way of holding a ship steady at the beach. This beaching method was the way to prevent broaching.

Broaching is the tendency of a vessel to turn from its Steerage way to a position parallel to the beach, broadside to the incoming wave front. This phenomena is caused by the interplay of forces taking place in the surf zone environment. If a floating object is exactly perpendicular to the incoming waves and there are no other forces acting on the object, then that object goes temporarily into a state of unsettled dynamical sensitivity similar to a ball balanced on the top of a needle. Even the slivhtest angular force, or side-thrust, creates offset power instantly rotating the object about its center bowto-stern axle. This force increments in magnitude in seconds by additional transverse drag due to the sea currents along the shore. Rotational motion is being highly accelerated as the angle of the vessel to the -wave front increases. As more of the ships area becomes available to the drag forces, rotation increases both in speed and intensity second by second. As more forces find more surfaces on the sides of the vessel to press upon, the movement races out of control and continues until finally the object reaches a lstate of settled dynamic stability in the fully broached position parallel to the incoming waves.

Steerage in this broached condition is absolutely impossible. Once broaching has occurred, a ship is helpless and will founder soon, capsize and sink.

Unless constant dynamic adjustments are made to cornpensate for the always present but variable longshore currents, rip currents and differential wave fronts, and maintain the desired centre axle, broaching cannot be prevented by a ship.

In the surf environment, the length of the ship hull and its relationship with power distribution is an intricate matter. No single location for propulsion could oifset the broaching forces; therefore, the Small`Port Vessel holds itself in water deep enough to exercise power against variable currents and this power is distributed along the longitudinal axle of the vessel rather than at one or other end of the ship. In this form, the Small Port Vessel provides cargo handling without stranding or broaching. The sensitivity required to maintain the vessel in the desired position is exercised by three thrusters each capable of 360 turning radius and located in form of a triangle from the bow to the stern, therefore, in paralleling the bow-to-stern axis.

Referring to the drawing in detail, and first considering FIG. 1, an ocean going vessel is indicated generally at 10. The vessel 10, in effect is beached or anchored close to the beach B and, for illustrative purposes only, tanks and/or tractor-trailers, etc. are illustrated as being unloaded, lengths of which running up to 40 feet or more, for example. The upper deck 14 of the ship is relatively at and the forecastle 16 of the ship has a through passage 18 leading to the displaceable bow 20; see FIG. 2.

As illustrated in FIG. 2, and particularly for accommodating personnel on the upper deck, a removable superstructure 22 can be provided to afford protection against the elements and/ or to facilitate camouflage, for example.

The ship includes a unique hull 24 including a substantially conventional ocean-going keel, bow, etc., configuration from slightly aft of the rudder to the bow as generally indicated at C in FIG. 2, however, extending a substantial length aft of the rudder to the stern of the hull is a transom section T which in effect provides a bridge over the more radical and harmful broaching currents inshore and adjacent the beach B.

The transom section T includes an elongated Well 26 which opens into the stern of the hull and which can be a width of as much as 30 feet. Accommodated in the well 26 is an extendable ramp 28 (which can comprise a plurality of telescoping and oatable ramp sections) designed to accommodate the load of the tanks, trucks, etc. being unloaded.

The transom T and the ramp 28 afford a combined length to sutliciently bridge inshore currents which cause the more drastic broaching forces.

The arrows 1 of FIG. 1 indicate the normal surf extending out over an area from 150 to 300 feet from the shore of the beach B (riptide beneath). In addition to the normal surf 1, arrows 2 generally indicate the llow of the olf or out shore current. Due to the beach configuration, combined resultant forces of surf, undertow, off shore current and factors which cannot be readily isolated because of the many variables, an inshore or set current 3, generally parallel to the beach line, and having almost twice the force of the outshore current, causes an unusual broaching force on conventional hulls.

For example, some landing craft hulls of shallow draft are beached bow-first directly onto a beach and the underside of the hull is so angled as to substantially conform with the slope of the beach. Very little clearance is provided beneath the hull, and the inshore set currents are in effect dammed against movement and cause excessive pressure on the side of the ship upon which they are reacting.

The principle of bridging excessive currents has never been incorporated in the ocean going hulls. The bridging principle is utilized in the hull of the present invention, namely, the vessel is enclosed in water of sufficient draft to permit it to oat, and be anchored, while the transom T and ramp 28 bridges the detrimental set currents and the vessel can be readily unloaded or loaded, i.e. using fork lifts, cargo carriers, loaded trucks, etc. Further, the ramp 28 will be of an expendable character in the event rapid beach evacuation proves necessary, and, as will be described, the auxiliary propulsion units will afford additional means to stabilize the hull during these close-toshore loading and unloading operations.

Referring to FIGS. 2-5, it will be observed that the deck 14 is relatively flat and extends to the displaceable bow 20 of the ship. The bow 20 will be suitably hinged at 30, and suitable seals (not shown) will be provided. Hydraulic lift means shown generally at 32 will be provided to raise the bow 20 to the dotted line position. A second lships stern is indicated at S in FIIG. .2, and when the bow 20 is raised, vehicles, cargo, etc. can be moved down passageway 18 beneath the forecastle and onto another ship.

Referring to FIG. 3, and considering the undersurface of the hull 24, it will be observed that extending aft of the hull keel 34 is the skeg 36 flanked on opposite sides by reversible yscrews 38 powered by suitable power plants 40. A rudder 42 extends aft of the skeg as is conventional.

Since the vessel is not intended for beaching but holding itself to the beach line, the hull includes depending skirts 44; see FIG. 4, which project downwardly substantially the same distance, or slightly below, the skeg and rudder. In the event a relatively soft bottom is encountered during the surf operation, a substantial portion of the stern will be supported by the skirts 44 and the screws 38 will not become impaired by the soft bottom, etc. The skirts 44 combine with the skeg and rudder to form rearwardly and downwardly opening tunnels to substantially direct water flow to aid in rapid propulsion of the hull with maximum efficiency.

Indicated generally at 46 is an auxiliary bow propulsion unit, while disposed behind the primary screws 38 are aft

auxiliary propulsion units

48 and 50 disposed generally outboard of the rudder and adjacent the inner surface of skirts 44. Before the auxiliary propulsion units are described in greater detail, it will be observed that auxiliary unit 48 is offset aft with respect to unit 50 and it has been found that about a five foot offset is desirable. This offset is desirable ysince water thrust by the one propulsion unit should not interfere with the operation of the other or cause cavitation about the other unit and/or create eddy currents affecting the maximum efficiency of the thrusters This offset relationship et'nhances the ability to hold the ship against set currents as well as improves the ability to perform acute turning maneuvers substantially about its own beam.

Further, as will be described in detail, many types ot' retractable propulsion units have been proposed in the past. For example, auxiliary outboard motors have been retractably mounted on pleasure craft or larger vessels. The auxiliary propulsion unit details are by way of example only and the

units

48 and 50, instead of being vertically retractable, could be folded into a suitable hull recess, i.e. the unit could pivot about a transverse axis, as in the case of pivotal outboard motors. Referring to the auxiliary propulsion units, it will be observed that each is retractable within the hull 24, and in this the exemplary embodiment, are accommodated in a cylindrical recess;

these auxiliary propulsion units are shown by way of example only. The units 46-50 comprise independently driven, reversible screws, which are oriented about a vertical axis. Thus they may be operated independently, and/or in unison with the main screws 38.

The reversibility and rotatability of the auxiliary units 46-50 permit the hull 24 to be substantially rotated on its own beam as well as permitting the hull to be maneuvered without the use of tugs or auxiliary vessels. Further, under emergency conditions, and with all auxiliary propulsion units operating in unison with the main screws 38, the ship can be rapidly moved from its anchorage. Further, with all tive propulsion units operating, acute maneuvers at sea can be readily accomplished at high speeds and thus evasive tactics can be readily accomplished.

With respect to the surfing operations, the auxiliary propulsion units can be raised or lowered to the desired operating level oriented about their vertical axis, and operated to counteract any set currents tending to react against the hull and broach the vessel while close to shore.

Referring to FIGS. 2-4, 12 and 13, only auxiliary propulsion unit 50 will be described in detail since all of the auxiliary propulsion units are essentially the same. Unit 50 is accommodated in a suitable cylindrical recess or well 52 in the hull 24, having a ceiling 54. Secured above to the ceiling 54 is a support frame 56 upon which is guided for vertical adjustment, a transmission 58. The transmission is connected to a drive shaft 60 for driving the propellor 62 of a propellor-and-rudder combination, and the propellor is rotatable about the vertical axis of a support housing 64 and position is controlled by a steering shaft 66. Depending beneath the rudder-and-propellor is a hull cover plate 68 conforming to the keel configuration in the case of unit 46, and the lower hull surface in the case of

units

48 and 50. 'Ihe transmission 58 is adjusted vertically by suitable hydraulic rams or motors 70.

These auxiliary thrusters per se do not form part of the invention, but only to the extent of their particular triangular orientation on the hull 24 and the general function afforded by these units to attain accurate maneuvers and improved stabilization. In effect, the vessel is afforded a stand-by propulsion system comprising each of the thrusters 46-50 individually or collectively and the main propulsion screws 38 used independently and in unison.

Additionally, the cover plates 68 can actively engage the bottom at which the vessel is anchored to and in dislodging it at low tide, for example.

The well 26 of transom T includes an aft gate 70 extending substantially the width of the hull stern, and the well 26 can be flooded in any suitable manner (not shown). The ramp 28 is floatable in the well 26 as well as on the surface of the seat onto which it is launched, thus imposing minimum loads on the landing mechanism 72. Further, by utilizing a oatable ramp which will be secured, but articulated, at the transom stern, wave movement will not impose excessive stresses.

The launching mechanism conveniently comprises one or more endless cables 74 entrained over a sheave 76 journaled at 78 on the inner end of the ramp 28. The cable 74 has secured thereon a latch 80 secured to the inner end of the ramp 28 to cause launching or retrieval of the ramp. Iournaled beneath the deck 14; see FIGS. 6 and 7, is a second sheave 82 which is power-driven through a suitable transmission-and-drive mechanism 84. The journal or shaft 78 as well as the latch 80 will detachably engage the ramp 28 whereby a rapid evacuation of the beach is necessary, the ramp can be readily jettisoned or left on the beach.

As indicated generally at 86; see FIGS. 6-11, are adjustable or foldable jack or stabilizer assemblies attached to opposite sides of the ramp 28. The ramp 28 can comprise a plurality of suitable channels filled with a floatable foam material and can comprise an enlarged oatable roller 29 journaled on a transverse shaft 31. The

roller 29 facilitates movement of the ramp onto the beach and the jacks 86 serving to adapt to the angle of the beach and stabilize the ramp; it will be understood that the ramp can readily be of a width sufficient to accommodate trucks, tanks, etc., thereon.

The jack assemblies 86; see FIGS. 8-10, are intermediately pivoted on shaft 88 and comprise a doubleacting hydraulic or pneumatic motor including a housing 90 to which the pivot shaft 88 is attached. The housing is adjustable about shaft S8 by operation of a fluid motor 92', see FIGS. 8, 9 and 11, for example.

The housing 90 includes therein a piston-and-rod element 94 and terminates in a lower, articulated food plate 96. Clearly, the jack or stabilizer assemblies 86 can be adjusted to various attitudes about the pivot 88 and can be extended to various depths.

Briefly in review, the elongated transom T in combination with the ramp 28 (which can comprise plural sections 28 as seen in FIG. 1) provides a bridge of considerable length permitting the hull to be anchored a considerable distance from the beach. Further, the thrusters on auxiliary power units 46-50, can be lowered and rotated to counteract any current forces tending to broach the vessel, yet the vessel will permit direct loading and unloading of cargo and/ or personnel onto an unprepared beach. Still further, the floodable well 26 facilitates easy launching of the ramp or ramps 28, 28', and the ramps can be readily abandoned if necessary.

Still further, the deck 14 is flat and provides a landing surface for helicopters, and can be enclosed as indicated at 22. The hull permits bow loading and unloading at sea or onto the beach via hinged stern 20. Additionally, the skirts 44 protect the screws 38 and prevent fouling in the beach bottom. Further, if necessary, the

auxiliary power units

48 and 50 can serve as jacks to free the hull when leaving a beach during lowtide conditions. Further, units 46-50 serve to not only stabilize the hull, but to permit acute maneuvers, as well as providing a supplemental as well as increased source of power during emergency conditions.

lt will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not limited to what is described in the specification.

What is claimed is:

1. A vessel comprising an ocean-going hull including a substantially flat, top deck, said hull including a keel substantially parallel to said deck, said hull including a substantially elongated hull-transom projecting aft of said keel for bridging set currents adjacent a beach, said hull including propulsion means aft of said keel, said transom being disposed above said propulsion means, said hull-transom including a well below top deck and opening at the hull stern, and at least one ramp telescopically disposed in said well, and means for positioning said ramp in a cargo-transfer position at the stern of said transom.

2. The structure as claimed in claim 1 in which said ramp comprises a oatable element.

3. The structure as claimed in claim 2 in which said well comprises a Water-tight compartment whereby the well can be ooded and said ramp will oat in said well and be readily moved therein.

4. The structure as claimed in claim 1 in which said ramp includes jack means for engaging a beach surface to stabilize said ramp.

5. The structure as claimed in claim 1 including means for detachably coupling said ramp to said transom whereby said ramp can be readily jettisoned.

6. The structure as claimed in claim 1 in which said hull includes aft, depending skirt portions rearwardly or the keel and extending substantially to the depth of said keel, said propulsion means comprising primary screw means disposed between said depending skirts whereby said skirts maintain said screws in an operative condition.

7. The structure as claimed in claim 1 in which said propulsion means comprises auxiliary propulsion units disposed in a triangular relation on said hull, one of said propulsion units being disposed forward adjacent the bow, said hull including a skeg portion, the other two propulsion units being disposed aft of the skeg portion and being offset transversely of said keel, the other two propulsion units being Offset aft with respect to each other, each of said propulsion units being rotatable about an axis of 360 whereby acute turning maneuvers can be accomplished at sea and in shore, the hull can be held stable at sea without anchoring, maximum lateral thrust can be attained by the auxiliary propulsion units, and the hull can be maintained stable, close inshore against set current broaching forces.

8. The structure as claimed in claim 7 in which at least said other two propulsion units are retractable toward and away from the undersurface of said transom.

9. A vessel comprising an ocean-going hull including a substantially flat top deck, said hull including a keel substantially parallel to said top deck, said hull including a substantially elongated hull-transom projecting aft of said keel for bridging inshore set currents adjacent a beach, said hull including propulsion means aft of said keel, said transom being disposed above said propulsion means, said propulsion means comprising primary and triangularly disposed auxiliary propulsion units, one of said auxiliary units being disposed adjacent and aft of the hull bow generally at the keel line, the other auxiliary units being disposed beneath the transom in spaced relation from a projection of the hull keel line.

10. The structure as claimed in claim 9' in which said auxiliary propulsion units are retractable into said hull and are rotatable 360 about a vertical axis.

11. A vessel comprising an ocean-going hull including a. substantially flat top deck, said hull including a keel substantially parallel to said top deck, said hull including a substantially elongated hull-transom projecting aft of said keel for bridging inshore set currents adjacent a beach, said hull including propulsion means aft of said keel, said transom being disposed above said propulsion means, said hull including a pivoted stern portion, said deck defining a through passage from stem to stern for facilitating bow transfer of cargo.

12. The structure as claimed in claim 11 in which said hull includes means for enclosing said through passage.

13. The structure as claimed in claim 11 in which said propulsion means comprises primary and triangularly disposed auxiliary propulsion means, said auxiliary propulsion means comprising one unit disposed adjacent and aft of the hull bow generally at the keel line, and other auxiliary units being disposed beneath the transom in spaced relation from a projection of the hull keel line.

References Cited UNITED STATES PATENTS 2,341,866 12/1968l Higgins 114-60' FOREIGN PATENTS 998,974 9/ 1951 France.

ANDREW H. FARRELL, Primary Examiner U.S. Cl. X.R. 114-43.5