A watercraft according to the present disclosure may include an outer hull that defines an interior or hull cavity, and a ballast system located within the hull cavity. The ballast system may include at least three ballast tanks longitudinally distributed along the hull cavity, and each of the tanks being configured to be independently operated enabling selective entrapment of ballast at three or more different longitudinal locations to enable an intentional shifting of the longitudinal center of gravity (LCG) of the watercraft relative to the design location of the LCG of the watercraft. The watercraft may include at least a forward, a center, and an aft ballast tank, and in some embodiments, additional tanks, in some cases in sponsons, may be included and/or one or more of the forward, center and aft tanks, may be further subdivided for additional active LCG control.

A grounding skeg for a landing craft configured for stem landing onto, and setting off from, a ground surface, the grounding skeg including: an elongate grounding body having a fore end and an aft end; and a removable pulling propeller functionally connected to the fore end of the body; wherein the pulling propeller is able to drive the landing craft ahead and astern; and the grounding body is locatable on the landing craft such that: the grounding body provides contact with the ground surface during stem landing of the landing craft; the fore end of the grounding body faces a bow end of the landing craft; and the aft end of the grounding body faces a stem end of the landing craft.

Techniques involve utilizing a multi-track cargo handling assembly to guide individual cargo items in parallel tracks to an aft end of a deck of an amphibious air cushion vehicle when unloading from the aft end. Such a multi-track cargo handling assembly includes a framework constructed and arranged to couple with the deck of the amphibious air cushion vehicle, and a set of guide rails coupled with the framework. The set of guide rails defines the parallel tracks and is constructed and arranged to constrain movement of the cargo items along the parallel tracks.

A boat ramp designed to collapse so the amphibious vehicle may be towed at highway speeds. The ramp fabricated of a central isosceles triangle hinged to the vehicle at its base flanks a pair of right triangles hinged along their hypotenuses such that the ramp can be folded over the vehicle during travel. The hinged portion is reinforced with removable steel channel during use.

Techniques involve utilizing a multi-track cargo handling assembly to guide individual cargo items in parallel tracks to an aft end of a deck of an amphibious air cushion vehicle when unloading from the aft end. Such a multi-track cargo handling assembly includes a framework constructed and arranged to couple with the deck of the amphibious air cushion vehicle, and a set of guide rails coupled with the framework. The set of guide rails defines the parallel tracks and is constructed and arranged to constrain movement of the cargo items along the parallel tracks.

A modular system, which may include a modular ramp for a landing craft, is described. For example, a ramp module according to some embodiments includes an enclosure defining a cavity, wherein the enclosure is configured to be removably received in a watertight recess formed in the hull of the landing craft. The ramp module also includes an extendible ramp operatively coupled to the enclosure and configured to be extended from the enclosure such that the ramp extends from the deck of the landing craft toward a shore to provide a support surface for unloading cargo onto or in close proximity to the shore. The extendible ramp is configured to be substantially fully retracted within the cavity, in some cases the enclosure forming an water tight seal with the recess in the hull and/or sealing the ramp, when retracted, in a water tight manner within its cavity.

A modular system, which may include a modular ramp for a landing craft, is described. For example, a ramp module according to some embodiments includes an enclosure defining a cavity, wherein the enclosure is configured to be removably received in a watertight recess formed in the hull of the landing craft. The ramp module also includes an extendible ramp operatively coupled to the enclosure and configured to be extended from the enclosure such that the ramp extends from the deck of the landing craft toward a shore to provide a support surface for unloading cargo onto or in close proximity to the shore. The extendible ramp is configured to be substantially fully retracted within the cavity, in some cases the enclosure forming an water tight seal with the recess in the hull and/or sealing the ramp, when retracted, in a water tight manner within its cavity.

A watercraft according to the present disclosure may include an outer hull that defines an interior or hull cavity, and a ballast system located within the hull cavity. The ballast system may include at least three ballast tanks longitudinally distributed along the hull cavity, and each of the tanks being configured to be independently operated enabling selective entrapment of ballast at three or more different longitudinal locations to enable an intentional shifting of the longitudinal center of gravity (LCG) of the watercraft relative to the design location of the LCG of the watercraft. The watercraft may include at least a forward, a center, and an aft ballast tank, and in some embodiments, additional tanks, in some cases in sponsons, may be included and/or one or more of the forward, center and aft tanks, may be further subdivided for additional active LCG control.

A ramp restraint apparatus for a vehicle includes an elongate, rigid restraint bar having one end rotatably attached to the ramp and a free end having a notch and a roller at its tip. The restraint bar travels over a bar support on a lock/release assembly mounted to a vehicle bulkhead. The bar support is shaped at one end to receive the notch of the bar and hold the bar in place when the ramp is fully deployed. A release arm has a cam follower that pushes up on and releases the restraint bar when the release arm is rotated, allowing the ramp to close. When the ramp is fully closed, a storage bracket receives and holds the inboard end of the restraint bar.

An amphibious air cushion vehicle includes an air cushion supported hull configured for travel on water and smooth land; a deck supported by the hull; and a dual-rail cargo system having tracks arranged longitudinally on along the hull cargo deck from an aft end. The tracks include (1) guide rails and rollers providing for guided sliding movement of palletized cargo along the tracks, and (2) locks for locking pallets in position during transport, The track is configured at the aft end for an unloading operation in which the locks are disengaged and the palletized cargo slides off the aft end onto underlying land as the vehicle is moving forward thereon. The track may be the one track of a single-track variant, or one of a pair of tracks in a two-track variant.