For years, Naval News has pursued the United States’ quest to field a new seaplane, brought forth by the need for more mobility in the seas with an amphibious aircraft that can take off and land on water.
China already fields the largest amphibious seaplane in the world, and while it is a commercial design, it can potentially have military applications if applied.
Obviously, the benefits of a U.S. military seaplane are real, and the world currently does have seaplanes such as the Japanese ShinMaywa US-2 and the Canadair CL-415. Both the Japanese and Canadian seaplanes can carry troops and a combat rubber raiding craft (CRRC), but they are not large enough to accommodate amphibious vehicles, jetskis, small boats, or oversize cargo, and those items may be what, in theory, the U.S. naval forces want.
Naval News has covered these seaplanes’ concepts and programs before:
- MC-130J floatplane (United States’ Special Operations Command (USSOCOM))
- REGENT Seaglider (US Marine Corps’ program)
- “Liberty Lifter” (Defense Advanced Research Projects Agency (DARPA))
- U.S. Navy seaplane program following the footsteps of USSOCOM, DARPA, and the U.S. Marines
U.S. Special Operations Command MC-130J Floatplane
The United States’ Special Operations Command’s (USSOCOM) MC-130J “Commando II” floatplane concept appears to be one of the simplest ideas: Take an existing Lockheed MC-130J military turbo-propeller cargo plane and add pontoons to the underside to make it float on water. With pontoon landing gears, the MC-130J can, in theory, drive itself onto the beach and runway. While the floatplane design does have benefits, it also has some design disadvantages that Naval News explored.
On October 23, 2024, a USSOCOM spokesperson replied with the following comment,
“Over the past few years, U.S. Special Operations Command has worked with industry partners to develop a data-driven model on how to operationalize new technologies, to include advanced explorative engineering projects such as the MC-130J Amphibious Capability (MAC). It’s a capability we can pursue further if called upon, but we have paused these efforts for the time being to invest in other modernization priorities. USSOCOM continuously reviews and explores the best way to support U.S. Warfighter and Joint Force requirements.”
Col. Timothy Bronder, USSOCOM Program Executive Officer for Fixed Wing Aviation Programs
Comments on the MC-130J Floatplane
Naval News contacted Mark Cancian, Senior Adviser, Defense and Security Department for the Center for Strategic and International Studies (CSIS) for comment. Cancian replied via email in December 2024: “Seaplanes faded from the US inventory as the Navy got access to a global network of airfields. The penalties associated with landing and taking off in the water were no longer worth paying. That’s still mostly true. However, three missions might bring seaplanes back as a niche capability: Supporting Marine Corps distributed operations, long-range air-sea rescue, and SOF insertions. The Marines are struggling to build a logistical support system for their planned distributed operations of littoral forces. Seaplanes might be a piece of that solution. The Navy is facing the possibility of major ship losses in a great power competition, something it has not faced since 1945. Finally, SOCOM wants a way to insert larger and better-equipped forces over long distances than can be done with small boats or parachutes. However, if such an aircraft does enter the inventory, it will be in limited numbers because other aircraft can handle most missions more efficiently and in a wider set of weather conditions.”
When asked why the U.S. doesn’t acquire readily available off-the-shelf seaplanes such as the Japanese ShinMaywa US-2, Cancian replied, “I don’t have a good answer for you. DARPA may be more interested in developing the technology than in fielding a near term system. However, the Marine Corps needs something immediately. The C-130J floatplane has the advantage of using an existing platform though the system seems to have faded…”
Brent Sadler, Senior Research Fellow for Naval Warfare and Advanced Technology in the Allison Center for National Security at the Heritage Foundation, said this about why USSOCOM might have decided not to buy the Japanese ShinMaywa US-2. “My understanding is that production of at least the US-2 is limited so added demand from a U.S. purchase may take time to meet.”
U.S. Marine Corps’ REGENT Seaglider
The United States Marine Corps (USMC) plans to field the REGENT Seaglider for logistical resupply missions and signed a contract in October 18, 2023 for $4.75 million to demonstrate the Seaglider to the Marines.
According to REGENT, “Seagliders are a hydrofoiling wing-in-ground effect craft that operate exclusively in the maritime domain. They address a recognized gap within the U.S. Department of Defense for high-speed, low-cost, low-signature, runway-independent mobility in the littorals and fulfill a range of mission sets including troop and cargo transport, expeditionary advanced base operations, and communications. REGENT’s Viceroy seaglider can carry 12 passengers or 3500 pounds of payload and travel up to 180 miles on a single charge.”
Naval News sent the U.S. Marine Corps an inquiry about the status of their Seaglider program and received this comment on November 15, 2024 from the Communication Strategy and Operations, Combat Development and Integration, spokesperson.
“Marine Corps Warfighting Laboratory (MCWL) is currently performing an exploratory investigation into maritime prototypes that exploit Wing-In-Ground (WIG) effect to achieve high speed marine logistical transport. WIG vessels pose a unique capability to provide high speed (> 100 knots) while being capable of certification as a maritime craft rather than an aircraft through the rules and regulations established by the International Maritime Organization (IMO). MCWL is currently only looking at Type A WIG craft that can only operate in WIG ground effect and are not dual certified as aircraft. Seaplanes are classified as aviation platforms while WIG vehicles are classified as maritime craft.
In FY24, MCWL established an Other Transaction Agreement (OTA) with REGENT to further investigate their hydro-foiling all-electric “Seaglider” being developed for both defense and commercial applications. The nearly $5 million contract will test out hydrofoiling Seagliders to provide an innovative solution for medical evacuation and resupply in littoral regions. Goals of the program are to validate the Seaglider’s ability to operate in each of its hull, foil, and wing-borne modes of operation, inform risk reduction and craft-level certification requirements, and understand the vehicle’s potential in military operations, including maneuver and transport operations. A live technical demonstration of the full-scale prototype is planned for fiscal year 2025.
Although MCWL is not currently investigating seaplanes for military logistics, seaplanes have played a very important role in historic conflicts and will remain a viable technology for future investigation.”
U.S. Marine Corps’ Combat Development and Integration spokesperson, November 2024
DARPA ‘s “Liberty Lifter” Wing-in-Ground Effect Cargo Seaplane
Naval News has covered the Defense Advanced Research Project Agency’s (DARPA) “Liberty Lifter” here. As Naval News stated in June 2022, “One of the `Liberty Lifter’s’ DARPA X-Plane Requirement is to transport two U.S. Marine Corps’ armored Amphibious Combat Vehicles (ACV), each with a gross weight of 67,500 pounds (30,617 kilograms) or 33.75 tons. This Requirement for the “Liberty Lifter” to carry two ACVs results in a total vehicle cargo weight of around 67.5 tons. This carrying weight is smaller than the initial DARPA WIG cargo plane rating of 100+ tons, but is about the cargo-carrying weight of a C-17 rated at 72.6 tons (160,000 pounds).”
Naval News contacted DARPA for a “Liberty Lifter” update and DARPA responded, prompting a questionnaire to be emailed. On October 10, 2024, Dr. Christopher Kent, “Liberty Lifter” program manager at DARPA, replied with the following answers.
Naval News: Is the U.S. Defense Department and DARPA serious about fielding seaplanes? Why or why not?
DARPA:“Looking at the missions the DoD has now and into the foreseeable future, there are many of them that would be well suited to a seaplane. These include higher-speed littoral personnel and logistics transport and search and rescue.
From a DARPA perspective, yes, we are serious about demonstrating and making this technology fieldable. Liberty Lifter is making a strategic investment to design, build, float and fly a roughly C-130-sized X-plane utilizing technologies that make potential cost-effective production and fielding a reality.
A long-range, runway and port infrastructure independent vehicle like Liberty Lifter is crucial to successful littoral operations in the Pacific should a conflict occur. The remoteness, lack of runways and lack of ports on many Western Pacific islands make traditional logistics support nearly impossible. Even if there are suitable ports, the time it takes to ship supplies across the Pacific is unacceptable in a time-sensitive environment.
Liberty Lifter’s large cargo capacity and operational flexibility make the design optimally suited for humanitarian assistance/disaster relief missions or response to a mass casualty at sea. There is no currently no platform that can get on-scene in a timely manner and rescue large numbers of personnel on the open ocean.”
Naval News: Is there any funding or Program Requirement for a seaplane as of Fall 2024? Why or why not?
DARPA:“The DARPA Liberty Lifter demonstration program is funded through completion. Regarding actual Program Requirements, this role does not reside at DARPA but DARPA is working with the requisite stakeholders across the DoD is doing studies to define mission needs and required capabilities for a potential seaplane Program of Record. From a DARPA perspective, a platform based on Liberty Lifter has the potential to address multiple DoD capability gaps including response to mass casualty at sea, personnel recovery, logistics support in expeditionary environments, and runway independent air vehicles.”
Naval News: Has any progress been made with DARPA and the other military branches regarding new seaplanes?
DARPA:“DARPA continues to develop the Liberty Lifter program targeting a
transition into the next phase of the program in FY25 which will include detail design and demonstration planning.”
Naval News: Why not buy a foreign seaplane such as the Japanese ShinMaywa US-2?
DARPA:“An existing seaplane design such as the US-2 could potentially serve as a gap-filler to provide some maritime search-and rescue capability. However, current seaplanes’ limitations on range, cargo capacity, and cost to acquire and operate present significant challenges that could be addressed by a larger, purpose-designed platform like Liberty Lifter.”
Naval News: When can we expect to see the new DARPA seaplane enter service, and in what form?
DARPA:“DARPA’s Liberty Lifter X-Plane demonstrator is projected to fly in FY 2029. After completion of the DARPA demonstration program, the X-plane will be available to the Services for follow-on demonstration. A successful demonstration campaign will enable assessment of the Liberty Lifter concept’s military utility, and lessons learned from the Liberty Lifter program will inform DoD requirements development and acquisition strategy for a potential follow-on Program of Record.”
U.S. Navy’s Seaplane Programs
With all the hype and programs about seaplanes, ostensibly, the client will be the United States Navy. Naval News contacted the U.S. Navy for any status on any seaplane programs. After an email transfer to the Naval Air Systems Command (NAVAIR), on September 16, 2024, the U.S. Navy’s NAVAIR spokesperson said over the phone that, “There is no seaplane requirement,” which basically means that the U.S. Navy is not actively engaged in any seaplane programs.
Brent Sadler, Senior Research Fellow at the Heritage Foundation, had this to say about seaplanes to Naval News on December 9, 2024:
“A few thoughts here on the seaplane idea:
1. Access to remote or even damaged airfields due to conflict or natural disasters makes the seaplane a worthy option for modern militaries and coast guards.
2. Where environmental or costs prove too prohibitive to connecting smaller island communities to global trade or even crisis response, the seaplane will be an ideal option.
3. Japan has operated seaplanes for a variety [of] roles, many I witnessed firsthand as a junior officer and on staff of Seventh Fleet based in Yokosuka, Japan. Time for the U.S. to invest in this capability for use first in and amidst the Pacific Islands.”
Brent Sadler, Senior Research Fellow at the Heritage Foundation
