The EPF is able to transport U.S. Army and U.S. Marine Corps company-sized units with their vehicles, or reconfigurable to become a troop transport for an infantry battalion.
The EPF has a flight deck for helicopters and a load ramp that will allow vehicles to quickly drive on and off the ship. The ramp is suitable for the types of austere piers and quay walls common in developing countries. EPF has a shallow draft (under 15 feet (4.6 m)).
A EPF is essentially an aluminum twin-hull catamaran shell containing four diesel engines, rudimentary control facilities for up to 40 crewmembers, and 312 airline-style passenger seats, along with an expansive flight deck on the top. The rest of the vessel is an empty 20,000 sq ft (1,900 m2) mission bay that can be loaded to carry whatever cargo is needed. Vehicles and cargo are loaded and unloaded by a ramp that can support up to 100 tons of weight. Although designed for a military crew of 46, the ships usually have a crew of just 26 mariners. The passenger room contains reclining seats with overhead televisions and racks for weapons and equipment. A vessel has 104 permanent berthing spaces. Without resupply, it can support 312 embarked personnel for four days, or 104 personnel for 14 days.
The design is similar with the Hawaii Superferry, also built by Austal USA.
The EPF has a greater level of comfort for the crew than larger Navy ships. The stateroom-style berthing areas for the ship's crew have private features like toilet stalls, outlets, air conditioning, and even thermostats. The same can not be said for the passengers, who may need to apply "Hot racking"-style living arrangements of available berthing bunks if necessary. There is no gym on board, nor soda machines or candy machines. There is no ship's store in the typical Navy sense of the term, but rather the ship's captain may unlock and sell ship's coins and other ship-specific paraphernalia on a case-by-case basis.
One disadvantage of the ship's design is stability in rough seas and at high speeds. At 10 knots in calm sea states, the hull can roll up to four degrees to each side, while conventional ships would roll very little, which would increase if the ship goes faster in rougher conditions, raising the possibility of seasickness. To achieve its top speed, the ship has to be traveling in waters not exceeding sea state 3 (waves up to 1.25 m (4.1 ft) high). At sea state 4 it can travel up to 15 knots, travel only 5 knots in sea state 5, and has to hold position in any sea state higher; while this might be seen as an operational limitation that can delay its arrival to port facilities, the ship was intended to operate closer to shore rather than in blue water conditions.
As of late 2014, a EPF costs $180 million to build and has an annual operating cost of $26 million.
The U.S. 4th Fleet has expressed interest in using the EPF as a low-cost ship for performing drug interdiction missions around Central and South America. U.S. Southern Command is experiencing a shortage of Coast Guard cutters available to interdict drug runners due to ship age and budget cuts. In May 2013, the HSV-2 Swift conducted a drug interdiction patrol, showing an aluminum catamaran was capable of performing the role. A EPF is capable of embarking a Coast Guard Law Enforcement Detachment (LEDET).
The EPF has no weapons or defensive systems to fulfill combat missions, but the Navy is looking to expand its roles to include re-supplying special operations forces and conducting humanitarian assistance missions. Chief of Naval Operations Jonathan Greenert has suggested using the ships as a cheaper way to perform counter-piracy missions to free up blue-water combatants. Offensive armament and defensive measures against pirates would be handled by a security team on board, and a EPF's speed would also be a good defense against an attack by pirates. The Navy is experimenting with using the EPF as a hospital ship by setting up an expeditionary medical unit (EMU) inside the mission bay. Although it wouldn't be able to conduct the same tasks as a full-size hospital ship, large hospital ships are slow, while the EPF can serve as a quick transit platform for rapid medical response.
After various tests to explore the EPF's suitability to perform different missions, the ship was found to perform its primary role of intra-theater transport effectively, but had extreme difficulty in carrying out other suggested missions. When performing at-sea transfers of equipment with a Mobile Landing Platform (MLP), the EPF ramp used for vehicle transfers could not effectively intemperate with it in open ocean sea states of 2-3, and was determined to only be able to work in calm sea states found in protected harbors, an unacceptable constraint for operational deployment; the Navy has been aware of the current ramp's limitations and is developing one for use in up to sea states 3-4. When deploying a SEAL Delivery Vehicle (SDV), the EPF's stern-mounted crane could launch it in up to sea state 3 conditions, but support surface craft were needed to get divers into the underwater vehicle, which could only be launched in sea state 2.
The Electronic System for this class is provided by General Dynamics Mission Systems. As the ship systems integrator, General Dynamics Mission Systems’ open architecture computing infrastructure (OPEN CI) enables the U.S. Navy to rapidly upgrade mission capability. OPEN CI connects proven, innovative hardware and software technology seamlessly and reliably. The infrastructure integrates the ship's electronic systems including; ship's computing environment, internal and external communications, electronic navigation, aviation, and armament systems, remote surveillance system, and entertainment & training system. The General Dynamics OPEN CI is also used on the Independence-class littoral combat ship (LCS), also built by Austal.
On 7 April 2014, the U.S. Navy announced that a prototype electromagnetic railgun will be installed onto USNS Millinocket (T-EPF-3) for at-sea testing in FY 2016. Though the ships are non-combatants, they were chosen for their available cargo and topside space and schedule flexibility. They will not be permanently installed on the EPF, and the Navy has yet to decide which ship classes will receive a fully operational railgun. The tests are to offer lessons to incorporate into a future tactical design and to gain knowledge on how to integrate the system onto a ship with modifications. The Navy later decided to mount the experimental railgun on USNS Trenton (T-EPF-5) instead, but has since found it unfeasible to schedule the test on the class due to operational demands.
The USMC is investigating changes to the EPF ramp to allow it to place Amphibious Combat Vehicles into the water near the shore. A single EPF could carry and deploy as many as 20-30 ACVs.
Marine Corps General John M. Paxton, Jr. has called the EPF "a very capable ship" for certain missions, but in consideration for serving as an alternate platform for Marines to use in amphibious operations as substitutes for amphibious assault ships, he claims several deficiencies including ability to operate in difficult sea states, ability to remain survivable in contested waters, a flight deck that cannot handle the heat of an MV-22 Osprey's engines during take-off and landing, lack of a well deck to launch amphibious vehicles at sea, as well as current lack of a "splash capability" where the ramp can allow vehicles to be driven off it into the sea. The EPF has been rejected as an alternative platform to base the MV-22 off of due to weight and the heat it generates being potentially damaging to its flight deck.
The EPF program combines the Army's Theater Support Vessel (TSV) program (dating from 2004) with the Navy and Marine Corps High Speed Connector (HSC) (requirement dating from 2004).
The EPF program received Milestone A approval in May 2006. The Navy awarded Phase One preliminary design contracts in early 2008, and a detail design and construction contract in the 4th Quarter of FY08.
The Navy's Program Executive Office, Ships will conduct acquisition for both the Army and Navy, but each service will fund its own ships. After delivery, each service will be responsible for manning, maintaining, and providing full lifecycle support for its vessels.
USNS Spearhead, the lead ship in the class, was launched in September 2011, and it is expected to be delivered to the Navy in early 2012.
The Navy expected to purchase 23 EPF vessels over 30 years.
On 2 May 2011, all Army JHSVs were transferred to the Navy.
On 5 December 2012, the first ship in the class, USNS Spearhead, was delivered to Military Sealift Command in Mobile, Alabama.
On 30 June 2011, Austal was awarded construction contracts for EPF-6 and EPF-7.
On 27 February 2012, Austal was awarded construction contracts for EPF-8 and EPF-9.
On 10 December 2012, the Navy awarded its final option under its current contract, and ordered EPF-10.
On 5 April 2013, the EPF program was added to the remit of the Littoral Combat Ship Council, so that the capabilities of both ship types could be considered together.
In 2014, the USN considered outsourcing the management of the fleet, but concluded that the ships would continue to be manned by civil service mariners.
Funding for the construction of an eleventh EPF was appropriated by Congress in the FY 2015 National Defense Authorization Act. The procurement of long-lead-time material and initial engineering support for the Expeditionary Fast Transport (EPF) 12 (formerly Joint High Speed Vessel 12) was announced on 5 May 2016 under the Naval Sea Systems Command's contracting activity (N00024-16-C-2217). On 16 September 2016, Austal was awarded a contract to design and construct EPF-11 and EPF-12.
The Army and Navy have been operating HSVs for some years, including such notable vessels as;HSV-X1 Joint Venture (joint Army/Navy)
HSV-2 Swift (Navy)
USAV Spearhead (TSV-X1) (Army)
MV Westpac Express (HSV-4676) (Navy)
Also of note;USNS Guam (HST-1) (Navy)
Sea Fighter (FSF-1) (Navy)
Sea Shadow (IX-529) (Navy)
Sea Slice (an experimental HSV) (Navy)
In June 2011, a fifty-ton module was damaged at the Austal shipyard in Mobile during the construction of USNS Chocktaw County.
In 2013 a Frost & Sullivan report predicted that sales could be made to APAC countries.
During operations in 2015, the first ship of the class, USNS Spearhead, experienced bow-damage from rough seas requiring more than a half-million dollars (USD) to repair. It was determined that a design change that Austral recommended to the Navy late in the design phase to save weight has resulted in a weakened bow structure. The first five ships in the class will need to have upgrades done to improve the superstructure, at a cost of $350k-$1.2M each. The remaining ships which are still various stages of construction will require upgrading following construction as well.
In early 2014, Austal announced it had been awarded a $124.9 million contract for two High Speed Support Vessels (HSSV) for a foreign customer, later revealed to be the Royal Navy of Oman. The HSSV has a similar catamaran hull design as the EPF and supports naval operations including helicopter operations, rapid deployment of military personnel and cargo, and search and rescue missions. It is 72.5 m (238 ft) long and can travel at 35 knots. An HSSV has a crew of 69 personnel with 69 berths, can seat another 250, and has a cargo capacity of 320 tonnes (350 short tons). Both are to be delivered by 2016.
Austal launched the first HSSV on 31 October 2015 at its Henderson, WA facility. It is RNOV Al Mubshir. The first HSSV was delivered to Oman on 20 May 2016.