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High-Capacity Alongside Sea Base Sustainment (HiCASS)

The Sea Power 21 concept relies on 4 pillars - Sea Strike, Sea Shield, Sea Basing, and FORCENET. The focus of the ExLog FNC is enabling Sea Basing. The fundamental shift from using host nations or captured land bases for USMC logistics bases to doing the bulk of the USMC logistics at sea is one of the biggest challenges that flow from Sea Power 21. The USMC Ship to Objective Maneuver (STOM), Operational Maneuver from the Sea (OMFTS), and Expeditionary Maneuver Warfare (EMW) future doctrine all emphasize mobility of forces on the sea, from the sea, and on the land. The significant emphasis on mobility requires the logistics tail that must maneuver ashore to be reduced. In order to achieve the vision, USMC logistics must be delivered reliably, responsively, and directly to the employed units requiring the items with the minimum footprint ashore.

These requirements pose three very significant challenges. First, the logistics chain must be capable of a substantial throughput rate. The current estimates are that in a high-intensity environment, the USMC Sea Based Echelon and support units will require on the order of 1,000 short-tons of logistics daily. This is roughly the equivalent of sixty-one 20-foot ISO containers daily.

Second, the logistics chain must be responsive. The Sea Based logisticians will utilize demand forecasting to anticipate demand and push fuel, water, Meals Ready to Eat (MREs), and spare parts to units to reduce the logistics load on those units. However, ordnance demand will vary radically depending on events of a given day, and other emergent demands may not have been anticipated. The logistics chain must be capable of responding promptly and effectively to meet these demands. If it cannot, the maneuver units will be forced to drag additional just-in-case logistics along.

Third, the logistics chain must provide reliable delivery of materials. Failures of the logistics chain due to supplier issues, transportation disruptions, weather, equipment failure, etc. can result in the maneuver units' distrust of the system. This leads to additional just-in-case logistics tails ashore with their inherent drag on the desired mobility.

One option is to leverage commercial shipping to augment the CLF during crisis periods, and to expand the defense sealift capability to support additional platforms beyond the current operating practices. Because the vast majority of commercial shipping is done by intermodal containers, it is anticipated that containerships will be the delivery vessel of choice. Investment is being made in the High Capacity Alongside Sea Base Sustainment (HiCASS) product line to enable the transfer of 20-foot International Organization for Standardization (ISO) containers, or other packaging that can be handled as a 20 foot ISO container (or Twenty-foot Equivalent Unit, TEU), from non-self-unloading containerships to the logistics ships. HiCASS is also investing in technologies to improve the Navy's ability to conduct UNREP safely. As part of naval distribution supporting Fleet and joint operations, the initial transition target is MPF(F), but it will be possible to provide this increased volume handling capability on other CLF ships as well.

The ENS concept requires the ability to selectively offload equipment and supplies in order to provide tailored forces and tailored support packages. The sea base must be capable of rapid resupply from commercial ships through the at-sea transfer of heavy intermodal packaging such as twenty-foot equivalent units (TEUs). New intermodal naval packaging that connects to form TEUs facilitates the breakdown and transshipment within the sea base. The focus for at-sea transfer of actual TEUs will be the MPF(F) ships with the other platforms within the sea base (CSG, ESG and CLF) capable of 12,000 pound intermodal container (similar to current Quad-Cons) transfer. Current breakbulk/palletized transfer capabilities will be maintained to sustain the legacy and coalition forces. The ExLog FNC is making investments in shipboard automation, robotics, packaging, and elevator technologies to enable rapid selective offload with minimal manpower and high stowage densities in MPF(F), and support increased sortie rates in CVN-21 by moving weapons quickly from the magazines to the flight deck. Ropeless elevator product lines are developing technologies, which, when integrated with automated warehousing systems for stores and weapons, will provide maximum flexibility to handle a wide variety of naval cargo. This capability will more effectively support future throughput requirements by enabling cargo to be rapidly moved from the automated holds to transfer and rearm stations on the upper decks. The ability to rapidly stow materials will also reduce the time alongside CLF ships during replenishment.

The High-Capacity Alongside Sea Base Sustainment (HiCASS) product line intends to address all of these issues, but will primarily address the issues related to a substantial throughput rate capability and reliable delivery of materials. With respect to throughput capacity, HiCASS focuses on concepts to increase both the single lift capacity for ship / platform to ship / platform transfer as well as the tons per hour transfer rate. With respect to delivery reliability, HiCASS focuses on concepts to reduce the sensitivity of the at-sea transfer systems to weather, especially sea state.

The HiCASS product line has two product areas. One is at-sea transfer between two large vessels and between a large vessel and a small vessel. HiCASS efforts will enable new approaches for heavy lift of fuel, cargo, vehicle, and personnel transfer, which now are performed by connected replenishment (CONREP) and vertical replenishment (VERTREP). It is anticipated that the technologies investigated under HiCASS will apply to UNREP capabilities as well. Alongside transfer of heavy cargo, including tanks, trucks, ISO containers, will be the fastest and most effective means of moving cargo from commercial and sealift ships without any special equipment. The Combat Logistics Force (CLF) is currently sized to support the carrier battle groups.

This concept enables the leveraging of commercial ships in lieu of fielding, manning, and maintaining additional CLF ships for the purpose of Sea Base sustainment. HiCASS consists of the transfer of cargo, vehicles, fuel, and personnel between two ships directly alongside each other underway at slow speed in the open ocean. The HiCASS means of underway replenishment may require: at-sea transfer that would permit transfers from one ship to another in half the time currently required for CONREP / VERTREP operations and station keeping technology and equipment to control the ships together and reduce the relative motions without risk of hull or superstructure damage. It requires that two ships maintain a steady position relative to each another for extended periods in conditions up through sea state 5. Little is known of the combined dynamic effect of forces acting on two vessels. These combined forces include hydrodynamic interactions in a random seaway, tensioned ropeway resultant forces, and rudder and propulsion forces required for the ships to maintain station.

HiCASS would be the first alternative in shifting 53,000-pound ISO containers from commercial, coalition, or strategic sealift ships with no special equipment directly to combat logistics ships and the Sea Base. HiCASS replenishment also may be a viable alternative to UNREP for many situations, and could reduce the time alongside the CLF ship for replenishment.

HiCASS has been extremely difficult under all but the calmest conditions because it is often conducted at anchor and the roll motion of the ship is significant. A Sea State 3 crane ATD has been demonstrated that will enable a crane to cancel out the load pendulation due to this roll in up to Sea State 3. This is a very significant improvement, but will be inadequate to provide a robust and reliable sustainment capability in the open ocean environment of Sea Basing.

In FY02, two studies were conducted independently by a John J. McMullen Associates, Inc. led team and by the Naval Surface Warfare Center Carderock Division that proved the feasibility of at-sea "skin-to-skin material transfer". These studies identified the fact that the U.S. oil transportation industry currently conducts at-sea "skin-to-skin" transfer of oil from Ultra Large Crude Carriers (ULCCs) and Very Large Crude Carriers (VLCCs) to lighterage tankers. This is done on the East, West, and Gulf Coasts due to the inability for the VLCCs/ULCCs to get into ports with their crude oil. The industry uses specially-trained lighterage pilots to perform the connecting and separating maneuvers and have had to put bow thrusters in their lighterage tankers to enable the ships to separate effectively. The industry states that mooring of tankers and transfer of liquid cargoes are conducted in Sea State 6 and below. However, they do not initiate the operation in these conditions. The U.S. Navy does dry cargo transfer between ships in a skin-to-skin configuration in up to Sea State 2.

The US Navy defines standard sea states by Significant Wave Heights, Sustained Wind Speeds, and Modal Wave Periods.  The standard used by the US Navy is the NATO STANAG 4194, Standardized Wave and Wind Environments and Shipboard Reporting of Sea Conditions.  The table below is an excerpt from STANAG 4194: 


Significant Wave Height*


Sustained Wind Speed


Modal Wave Period


Sea State






Most Probable


0.6 ? 1.25


11 ? 16


5.0 ? 15.2



1.25 ? 2.5


17 ? 21


6.1 ? 15.2



2.5 ? 4


22 ? 27


8.3 ? 15.5



4 ? 6


28 ? 47


9.8 ? 16.2


*Significant Wave Height- If all the wave heights (peak to trough) of a wave record are measured, the significant wave height is the mean value of the highest one-third of them.

Feasibility Study for Sea State 5 Skin-To-Skin Cargo Transfer Operations

HiCASS is more difficult than tanker lighterage in two significant ways. First, naval auxiliary ships and commercial containerships have high freeboard and/or long deckhouses when compared with oil tankers. The need to prevent these structures from colliding in a seaway is eliminated on tankers by small freeboard and mooring arrangements that provide longitudinal separation between deckhouses. Second, HiCASS will require transfer of rolling stock, break bulk materials, and ISO containers in addition to oil. Pumping oil through a flexible hose is a much easier problem than transferring a 20 ton container with a crane or a 75 ton vehicle with a ramp or crane.

In FY 03 JJMA conducted additional sensititivity studies addressing vessel sizes, mooring and fendering. Development of modeling and simulation tool was started to enable understanding of the hydrodynamic forces in a sea way with multiple vessels and integrating models of connection technologies into the simulation. This effort continued into FY04.

A HiCASS War Game was run in FY03 with results assisting in development of a transition process. The requirements of Heavy UNREP were integrated into the HiCASS product line and pursue technologies that will enable both capabilities.

A study was also commissioned to review material transfer issues at a fundamental level and assess the requirements to undertake material transfer in a seaway with a desire to dramatically increase capacity and operability in high sea states. This study was performed by a Naval Research Lab led team that included researchers from the Naval Surface Warfare Center Philadelphia, PA.

At-Sea Material Transfer - A Brief Study of Future Capabilities

The overarching strategy was to make a competitive award to 3 teams in FY 04 to provide a quick look at technology. An Industry Day was conducted on 23 October 2003 in preparation for a BAA solicitation in FY04. ONR anticipated down selecting to a single competitive award in FY 05 to a team consisting of an integrator and technology developers for the phased development, demonstration, and transition of the required technologies for HiCASS through FY 07. An at-sea demonstration is deemed necessary in order to overcome the resistance among operators to bringing two large ships together at sea. The single contract is intended to provide a framework for technology development that facilitates systems integrations downstream. Discussions are underway with the OPNAV N42 staff and the MPF(F) Program Office with regard to providing transition opportunities.

It is expected that team efforts will be required to develop innovative and integrated technology solution for a HiCASS capability. Such a technology solution must build on existing naval systems.

The BAA Solicitation in FY04 was issued in November 2003 and closed in January 2004. ONR received 18 Proposals in response to the BAA Solicitation from Industry Teams that included partners from Industry, Government Laboratories and Academia. Through a detailed Source Selection Process three industry led teams were selected. Contract awards were made in the third quarter FY04 to teams led by Rolls Royce, Oceaneering and Lockheed Martin.

The Rolls-Royce (RR) Team proposes to develop an innovative, integrated technology solution for High Capacity Alongside Sea Base Sustainment (HiCASS) in heavy seas. In the Team's vision, shuttle ships sustain the Sea Base using skin-to-skin (STS) replenishment. Sensing and measuring of the sea environment allows the receiving ship (nominally an MPF(F)) to determine the most favorable heading and speed to reduce relative motions during cargo transfers. Sensors and a situational awareness system on the MPF(F) allow the real-time assessment of relative ship motions and the distance, heading, and speed of the shuttle ship. Precision maneuvering equipment enables the MPF(F) to maintain a desired track and relative distance from the shuttle ship to support automated mooring and fendering.

The Oceaneering International, Inc. (OII) Team's innovation is in the integration of nine technologies to form the HiCASS Macro/Micro Crane (MMC). OII brought together innovations in the state-of-the-art for ship motion prediction from measured waves fields, fendering, crane configurations and actuation methods, controls, sensors and simulation technologies and produce a plan of nine technology advancement efforts that work together synergistically. The end result will be a technology demonstration of the OII Team HiCASS solution.

The Lockheed Martin team developed some innovative technologies, carry out engineering and system analyses of these technologies, integrate the technologies into a total systems solution, and demonstrate in a virtual simulation environment (the one- and three-wall CAVE) a HiCASS capability employing unique enabling technologies to support the sea basing concept. As a part of the total systems solution, Lockheed developed the process and designed the hardware and software to ensure safe and expeditious ship approach, connection of ships, minimization of relative motion between the ships, dynamic handling of the moored-ship assembly, and separation of the ships in open ocean environment and in sea states up to and including SS5. Lockheed also developed a system to maintain skin-to-skin contact between the two ships, minimize the relative motion between the ships, and prevent metal-on-metal contact between the ship hulls and superstructures. Finally, Lockheed developed a skin-to-skin transfer system to transfer cargo including, but not limited to, standard ISO containers, while underway in the open ocean in sea states up to and including SS5. The system will be capable of safely handling cargo transfer between the MPF(F) ship and both standard commercial container ships and small Navy landing and supply vessels.

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Page last modified: 07-07-2011 12:57:01 ZULU