Ship to Shore Connector: the USN’s New Hovercraft

SSC concept
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The Ship to Shore Connector (SSC) hovercraft program aims to build on the USA’s LCAC hovercraft experience, and retain the US Navy’s unparalleled transport options from ship to shore and beyond. LCACs launch from inside the well deck of an amphibious warship, then travel the waves at high speed, run right through the surf zone near the beach, and stop at a suitable place on land. Their cargo walks or rolls off. The LCAC(Landing Craft, Air Cushion) returns to the surf to pick up more. Rinse. Agitate. Repeat.

These air-cushioned landing craft are much more capable than the conventional flat-bottomed landing boats used by other countries, but that capability comes at a price. LCACs were expensive to buy, suffered from corrosion and maintenance issues, and remain quite expensive to operate and maintain after many years in service. The other problem is that tanks and other vehicles have gotten heavier, so carrying equipment like the Marines’ latest M1 Abrams can push current LCACs to their capacity limits.

Countries like France are designing fast catamaran landing craft for over-the-horizon delivery at a lower price point, and modern hovercraft offer new options of their own. The US Navy looked at the possibilities, then decided to ask for an upgraded version of the current LCACs. SSC was born, and in 2012 it finally moved into system development.

The Ship to Shore Connector

Changes: LCAC-SSC
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Initial plans for the SSC involved 80 hovercraft, including 8 development & test models, and 72 operational production hovercraft delivered through FY 2029. A Milestone C decision on low-rate initial production (LRIP) is planned for Q1 2015, and the SSC Program will obtain incremental LRIP approval to exercise craft construction options through planned DAB reviews. The program is scheduled to reach Initial Operational Capability in FY 2020, with 5 deployable craft and 1 production configuration training craft.

The SSC aims to use a number of new hovercraft technologies, in order to deliver improved performance, with less maintenance, while looking a lot like the LCAC from outside. Length and beam will be the same, while depth increases from 50″ to 56″.

The SSC is the 1st ship design implementation of Set-Based Design (SBD), wherein the government design locks in major details, while contractors make “detail design” changes to improve manufacturing and reduce costs. Lessons from the LCAC were part of that process, which included identifying the top 25 cost drivers in the existing fleet.

In the new SSC, technology is used to eliminate the loadmaster, leaving a 2-person pilot & co-pilot crew. Base weight capacity grows from 60 – 74 tons by using newer and more powerful engines (4 x 3955 – 4 x 5300 hp). That’s coupled with base weight improvements, thanks to a combination of AA 5083 aluminum with an advanced internal coating system throughout the structure, along with light and non-rusting composite materials. Composites are used in the 69″ lift fan (up from 63″), bow thrusters, 6-bladed rear propellers (replacing 4-blade propellers), propeller duct, rudders, and 4 shaft segments (replacing 12 steel shaft segments) from the engines to the rear propellers.

Its AE1107-derived MT7 gas turbine engines are connected to a sophisticated gearbox system that drives both propulsion and lift. Rolls Royce says that the new engines will increase the hovercraft’s power by 25%, while dropping fuel consumption by 11%. That will help extend range as well. Instead of aiming to deliver forces from 15 miles offshore, the SSC aimed at 25 miles. This distance was picked to give US Navy ships 2 shots at incoming missiles, which helps because the cost of the US Navy’s LPD amphibious assault ships has skyrocketed to $1.7 billion each.

Beyond these high performance drivers, the SSC’s drive train is simplified compared to the LCAC, electrical-hydraulic actuators are used throughout, climate control is improved, communication antennas get a redesign, and fire-fighting complies with new requirements by avoiding Halon gas.

This may be enough for the SSC to succeed on its own terms. The question is whether the US Navy can do the same with its ship to shore transport needs. The SSC’s 25 mile carry distance was also the driving force behind many of the (canceled) USMC EFV armored personnel carrier’s disastrous design decisions, from the size and weight of its propulsion to its vulnerable flat-bottom hull. That transit distance is much more appropriate for a hovercraft than an APC.

The question is whether 80 hovercraft are enough to handle the Corps’ needs for amphibious landing in threatened zones. The EFV program effectively voted “no” with its specifications, but the hovercraft option seems to be what the Navy/ Marine Corps team is left with. Perhaps ancillary programs like the Ultra Heavy-lift Amphibious Connector with unusual paddling foam tracks can fill in the gaps.

Contracts & Key Events

SSC concept
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Aug 27/14: SSC #101. Textron Inc. in New Orleans, LA receives a $21.9 million contract modification to build hovercraft 101 of the ship-to-shore connector (SSC) program. This would appear to be the 1st production option under the development contract (July 6/12). $2 million in FY 2014 Navy RDT&E budgets are committed immediately.

Work will be performed in New Orleans, LA (93.5%); Huntington Beach, CA (2%); Chanhassen, MN (2%); Coronado, CA (1.5%); and Minneapolis, MN (1%), and is expected to be complete by August 2017. US NAVSEA in Washington, DC manages the contract (N00024-12-C-2401).

LCAC to SSC
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Dec 20/12: Lead-in. Textron Inc. in New Orleans, LA receives a $23.3 million contract modification, exercising an option for SSC long lead time materials, advance planning, engineering, procurement services and technical manuals.

Work will be performed in Indianapolis, IN (37%); Camden, NJ (25%); New Orleans, LA (11%); Norway (8%), Great Britain (7%); Farmington, MI (6%); and Eatontown, NJ (6%), and is expected to be complete by June 2015. All contract funds are committed immediately, and US NAVSEA in Washington, DC manages the contract (N00024-12-C-2401).

Oct 22/12: Engines. Rolls Royce has been picked to supply its MT7 gas turbine engine for the SSC, and design and manufacture the hovercraft’s air intake and exhaust systems. On each hovercraft, the MT7 gas turbines will be connected to a sophisticated gearbox system providing both propulsion and lift.

The MT7 is derived from the AE1107 engine, which already powers the US Marine Corps’ V-22 Osprey tilt-rotor aircraft. Rolls Royce says that the new engines will increase the hovercraft’s power by 25%, while dropping fuel consumption by 11%. Rolls Royce.

March 2012: DOT&E. The Pentagon’s Developmental Test and Evaluation and Systems Engineering’s FY 2011 annual report includes a section on the SSC program:

“While the initial Test and Training (T&T) craft will remain as the primary test asset, the first production craft will serve as a potential risk mitigation should a backup craft be required during IOT&E. The SSC program completed competitive prototyping on the subsystem level… to demonstrate increased performance, reduced weight, improved maintainability or improved reliability depending on the system… Prototype testing was also completed on the Advanced Skirt (AS), which is currently being evaluated as a “Should Cost” item for incorporation at a later date.

…the program schedule timeline is inadequate to support a MS C decision in 1st quarter FY 2015 because full-up system level testing does not start until 2nd quarter FY 2016. DASD (DT&E) considers SSC as moderate to high risk because it is a complete redesign of the LCAC, which has a legacy of reliability, corrosion and performance issues. All major SSC systems are new and some have not been used in a marine environment. The Navy has identified SSC drive train integration; command, control, communications, computers and navigation (C4N) control system development; and main engine development as moderate probability of risk occurrence with significant consequences if the risk occurs… The SSC is a complex new design with all new components that should have full-up system level testing to support craft production decisions.”

June 22/11: PDR. Preliminary Design Review for the Navy’s base SSC contract design.

Dec 9/10: FBO.gov releases solicitation N0002411R2401 “19–Detail Design and Construction of Ship to Shore Connector (SSC) Test and Training Craft and Production Units”

Nov 4/10: Team Textron. Textron Marine & Land Systems opens the Textron Marine & Land Systems Win Center at its Slidell, LA facility. It will begin by housing the bid team for the U.S. Navy’s SSC program. Textron.

Boeing/MM SSC Concept

Sept 13/10: Team Textron. Textron and L-3 add Alcoa Defense to their SSC team. Textron Marine & Land Systems General Manager Tom Walmsley:

“With more than 100,000 lbs of aluminum in every craft, you want to make sure you have the undisputed world leader in aluminum on your team.”

Alcoa does more than just produce aluminum. They also design alloys for specific uses, and developing and manufacture high-performance aluminum structures that are optimized for a customer’s cost and weight. Textron Marine & Land.

May-June 2010: NAVSEA Stakeholders Steering Board conducts SSC Critical Design Review (CDR)

December 2009: Industry Day. SSC Industry Day, and release of draft specifications and drawing to industry.

Oct 13/09: Team Textron. Textron Marine & Land Systems and L-3 Communications announce their teaming agreement to pursue the Navy’s next generation Ship-to-Shore Connector (SSC) hovercraft program, and to further develop the Navy’s contract design using its proven detailed design-to-prototype build practices.

The SSC program could involve up to 80 hovercraft, with a total program value of $4 billion. Textron Marine & Land.

March 2009: NAVSEA Stakeholders Steering Board #2 approves SSC Functional Baseline Design

November 2008: NAVSEA Stakeholders Steering Board (SSB) #1 approve SSC Baseline Design.

November 2007: SSC Analysis of Alternatives Final Report signed by N85 & DASN Ships.

Additional Readings

• Textron Systems – Ship to Shore Connector.

• Textron’s Team SSC – Bid promotion site for the LCAC’s replacement – 2012 snapshot. Textron Marine & Land Systems’ team includes Alcoa Defense and L-3 Communications.

• Marinette Marine Team SSC – Bid promotion site for the LCAC’s replacement – 2012 snapshot. See also YouTube video for background. After Boeing dropped out, the core team was Marinette Marine, Oceaneering International, and Griffon Hoverwork.

• DID – LCAC Hovercraft: US Navy’s Champion Schleppers Get SLEPped. L-3 Unidyne is the primary contractor doing this work. Textron is the LCAC’s original builder.

Supplements and Alternatives

• Stars and Stripes (July 13/14) – UHAC: Marines’ amphibious craft propels, paddles in prototype trial. See also YouTube video. The UHAC can’t replace the fast SSC, but it may serve as a much-needed supplement that can deliver supplies farther ashore.

• US Navy (Feb 9/12) – French LCAT Visits Wasp. See also Photos; the catamaran proves to be fully interoperable. Going the other way, USN LCAC hovercraft have qualified as compatible with France’s Mistral Class LHDs.

News & Views

• Defense Media Network (Dec 9/11) – The Ship to Shore Connector: Building a Better LCAC.

• FBO.gov (Dec 9/10 – July 27/11, #N0002411R2401) – 19–Detail Design and Construction of Ship to Shore Connector (SSC) Test and Training Craft and Production Units.

• Boeing (March 7/11) – Ship to Shore Connector: A better ride to the beach.