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Amphibious Combat Vehicle Ramp Interface Modular Buoyant Kit (MBK) for Joint High Speed Vessel (JHSV) Stern Ramp


The United States Marine Corps has advised the Navy that it needs to develop a light weight kit that can be readily attached to the JHSV’s stern cargo ramp so that when the ramp is lowered directly into the water it would allow AAVs and ACVs to be launched and retrieved from the JHSV near the shore (splash-off). The Marine Corps needs a high speed shallow draft connector that can launch a dozen or more AAVs/ACVs within three miles from shore. These amphibious vehicles do not carry sufficient fuel to enable them to carry out their assigned mission ashore if they are launched from deep draft Amphibious Landing Ships positioned at a long standoff distance. The Navy is seeking concepts that do not require significant modifications to the ramp structure, but should rely instead on light weight discrete systems to protect the ramp from sea state-induced motion and facilitate desired transfer operations. The Navy intends to develop a kit that will permit the L&R of Amphibious Vehicles close to shore from shallow draft high speed JHSVs. The Navy seeks the development of an innovative compact lightweight MBK that can be stored inside the JHSV’s vehicle bay. The MBK will serve as flotation to the current JHSV stern ramp to facilitate launch and retrieval of the USMC ACVs and AAVs (Ref 1) through full Sea State 3 (SS3) with significant wave heights up to 1.25 meters without damaging the ramp. The primary purpose of the MBK will be to provide protection to the ramp from induced relative motions from the sea. The MBK also needs to be designed to accommodate the weight of the future Advanced Combat Vehicle (ACV) that is projected to weigh approximately 30 short tons and will be splash-launched directly into the sea via the stern cargo ramp and then driven back up the ramp from the sea and aboard the JHSV. The current stern cargo ramp that is installed in the JHSV has had structural failures when operated above its specified design condition. The current JHSV stern cargo ramp is designed to support vehicle transfer through SS1, flat seas up to 1 ft (Ref 2), during L&R (Ref 3). Torsion is particularly damaging to the JHSV ramp and its connections to the JHSV structure at-sea transfers. JHSV or receiving platform motions may impart dangerous accelerations to vehicles transiting the ramp. MBK development should be focused upon satisfying requirements in a cost effective manner. The MBK system should be portable enough to store in a Twenty-foot Equivalent Unit (TEU) meeting TEU tare weight restrictions of 47.6k lbs and be easily transferred from the vehicle bay to the stern “porch” with standard shipboard cargo movement forklift or similar gear. While JHSV does slow down to almost a complete stop prior to unfolding and deploying the ramp, the MBK must be designed so that it can be prepared for use by shipboard personnel while the JHSV is underway at speeds of up to 20 knots. As the ramp is being unfolded, the MBK should be designed to automatically position itself beneath the ramp prior to the ramp being lowered into the water. The MBK must be able to dynamically compensate for motion in SS3 while in use to ensure safe L&R. The MBK needs to be designed to operate in SS3 for the worst case condition in which the vehicle is being driven along the edge of the ramp instead of right down the middle of the ramp. It needs to be able to dynamically compensate for SS3 conditions using buoyancy, configuration, and other innovative techniques to prevent damage to the JHSV and the ACVs or AAVs during L&R. The addition of the MBK should also have little to no effect on ramp deployment and retrieval time. This will allow deployment of amphibious combat vehicles from the much more affordable JHSV platform rather than the traditional delivery by LPD 17 and Landing Craft Air Cushions (LCAC). PHASE I: The company will develop concepts for an MBK to enable the JHSV stern ramp to be used to launch and retrieve amphibious vehicles meeting the requirements described above. The company is expected to demonstrate the feasibility of its concepts through dynamic modeling and simulation to show that the concepts avoid damage to the JHSV and amphibious vehicles during splash-launch and recovery of heavy 30 ST loads in Sea State 3. Feasibility demonstrations must show that ramp structural design limits are not exceeded and that the cost of the MBK is affordable to the Navy; not more than $250K, however, the Navy seeks the most affordable solution capable of meeting the technical requirements. PHASE II: Based on the results of Phase I effort and the Phase II Statement of Work (SOW), the company will develop a prototype MBK for evaluation. The prototype will be evaluated by scale model test, modeling, and simulation to determine its capability in meeting the performance goals defined in Phase II SOW and the Navy requirements listed in the description for an innovative compact lightweight modular MBK. The MBK prototype will be tested in the laboratory on a motion platform to demonstrate that the MBK can accommodate amphibious launch and recovery in Sea State 3 without exceeding the design limits of the JHSV and without damage to the JHSV, the amphibious vehicles, or the MBK. PHASE III: The company will be expected to support the Navy in transitioning the technology for Navy use. The company will finalize design and fabricate full scale production prototype for the JHSV stern ramp, according to the Phase III SOW, for evaluation to determine its effectiveness in an operationally relevant environment. If the MBK successfully completes the relevant environment evaluation, the Navy expects the company to support full-scale test and validation during a Fleet Experiment to certify and qualify the system for Navy use.
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