Revisiting the DARPA "Sea Train"

About 3 years ago, I posted the following about a DARPA research project involving the transit of unmanned vessels across long ocean distances. I can envision the use of such vessels in a sustainment role for remote forces, as I will discuss later.

A recent CIMSEC thought piece by CDR Todd Greene has some interesting thoughts along these lines THE NIGHTTRAIN: UNMANNED EXPEDITIONARY LOGISTICS FOR SUSTAINING PACIFIC OPERATIONS:

Supplying widely distributed EABs of varying size, composition, and organic capability presents two sets of challenges – long-range transits across thousands of miles of contested open oceans, and last-tactical-mile delivery over an unimproved shoreline and into the hands of stand-in forces. Today’s systems mainly focus on one or the other, but there is nothing that can do both well.

Innovation must be directed at designing connectors that can bridge capability between these two distinct challenges. They must be able to transit oceanic spaces that feature hostile environments stemming from the open ocean environment and adversary capability. After traversing these many miles, the same system must somehow get supplies across a beach and into the hands of the stand-in force. Innovative connectors are necessary to provide the vital link between the stand-in forces and seabases or logistics hubs.

I think the good CDR is correct, but I also think the innovation connectors are being worked on today:

(Begin quote from my 2020 post)

[Back in 2000], the DoD's Defense Advanced Research Projects Agency announced the concept of a "Sea Train":

The Sea Train vessels independently depart a port under their own power to reach a sortie point notionally 15 [nautical miles, or nmi] from the pier. The four independent vessels then begin the Sea Train mission by assembling in Sea Train configuration and completing a notional 6,500 nmi transit through varied sea state conditions that might require re-routing to optimize travel times or vessel seakeeping. The Sea Train then arrives at a disaggregation point, where the four vessels begin independent yet collaborative operations consisting of transits, loiters, and sprints in varied sea state conditions. The vessels then arrive at a sortie point to begin the aggregation process and conduct a Sea Train sprint from the operational area. The Sea Train then returns to normal transit speed for the remainder of the transit in varied sea state conditions, disaggregates outside of port and the vessels self-navigate to a pier.

There has been research in this area as set out here (pdf) in a paper by Igor Mizine and Gabor Karafiath:

A sea train is an arrangement of multiple hulls connected together to form a longer assembly of vessels. The sea train configuration takes advantage of fundamental hydrodynamic principles to reduce the drag of the assembled train below that of the individual components proceeding separately. In some circumstances the sea train arrangement can also offer operational advantages.

WHAT IF?

What if we develop large numbers of these "sea train" modules, including several loaded with generators, sensors, and "missiles in a box," they can serve as "accompanying assets" to a battle force. Such vessels, arriving in an area of interest could decouple, spread themselves out over a wide area and allow for a very wide distribution of lethality. 

Other "Sea Trains" may be equipped with machine shops, cranes, additive manufacturing equipment, or replenishment munitions or fuel. These units could be held in "safe havens" and brought to the fleet as needed. None of them need be manned which makes them far less expensive to construct. Each could carry sufficient habitability containers to provide comfort for technicians or other personnel needed to operate equipment at their needed destination. 

 The larger the number of sea train modules, the great the the likelihood of needed components reaching the fleets on a timely basis. With enough units, even the expanse of the Pacific can be "shrunk."

As with WWII merchant shipping, some elements of a sea train could contain self-defense detection and weaponry, remotely monitored, but capable of self protection when authorized by a "human in the loop." Such equipment might include ASW-capable drones, or ASuW assets. 

Further, the use of unmanned but armed surface and subsurface could take the place of manned convoying ships.

COMMUNICATIONS

A key issue in discussing using unmanned vessels in the manner described above is communicating with those vessels to direct their positioning and, in the case of combat. controlling their weaponry. 

Obviously, with the towed missile barge such communications could be done through a cable connection piggy-backing on the tow line. 

With vessels within line of sight of the controller ship, the comms may be done through lasers or line of sight radios.  It is also conceivable that light weight fiber optic lines could connect units even several miles distant.

In certain environments, satellite links may be available. If those are blocked, manned or unmanned aircraft may serve as relay platforms. Indeed, the concept of solar powered high-altitude communications air systems placed to create an continuous link along the projected sea routes is not far-fetched. AeroVironment, among others, has been working along these lines for almost four decades. 

Explained in their video concerning their HAPS project - which could obviously be modified for military use, if needed:

The point is that we currently have the technology to distribute lethality at a much lower cost than the cost of new ships. We just need to get moving on experimenting with these technologies to find the right mix to provide the tools needed by our Navy and Marine Corps. 

***

UPDATE: DARPA "Sea Train" concept image:

DARPA offers up contract bid info here:

The Defense Advanced Research Projects Agency (DARPA) Tactical Technology Office (TTO) seeks to enable extended transoceanic transit and long range naval operations by exploiting the efficiencies of a system of connected vessels (Sea Train). The Sea Train will demonstrate long range deployment capabilities for a distributed fleet of tactical Unmanned Surface Vessels (USVs).

(End quoted post)

UPDATE 2023: DARPA has continued its Sea Train work. Technology and software is being worked on DARPA’S SEA TRAIN TO MAKE WAVES WITH TEXTRON SYSTEMS AUTONOMY ENGINE AT THE HELM

If these "No Manning Required Ships" are developed, their configuaration is up to the Navy, not DARPA, see DARPA Updates On Its Sea Train And NOMARS USVs:

DARPA: “NOMARS is not a barge; it is a MUSV [medium-sized unmanned surface vessel]. However, to the other part of your question, we are attempting to develop a next-generation MUSV class that has significantly higher reliability and availability, and carry significant payload for its size. Leveraging any existing design would defeat the purpose of the DARPA program.”

Ultimately what payload the US Navy would have future generations of USVs carry is part of their decision space, but there is nothing unique to the NOMARS philosophy that makes it more compatible with warfighting payloads vs. logistics payloads.”

As set out in Expeditionary Autonomous Transports, the Navy is experimenting with developoing an automous Expeditionary Fast Transport. Though the EFT is not "Sea Train," the technology is not all that different.

There is no reason not to develop "sea trains" composed of various sized units which can contain feature that would meet the two challenges CDR Greene discusses above - including an asset to cover the proverbial "last mile"delivery. If the need is there, a tool can be found to make it work.

Simplifying things by using unmanned tools

Interesting piece from Sam LaGrone at USNI News Navy Wants 100 Unmanned Ships Monitoring Middle East Waters by Next Year

The United States and its allies want a force of 100 unmanned surface vessels patrolling waters from the Red Sea into the Persian Gulf by next summer, the commander of U.S. 5th Fleet said on Tuesday.

“We’ve established a goal to have 100 unmanned surface vessels available for patrol in waters around the Arabian Peninsula by the end of the summer of 2023… with a majority of the systems coming from our international and regional partners,” U.S. 5th Fleet commander Vice Adm. Brad Cooper said during an address at the U.S. Coast Guard Academy.

For the last year, U.S. Central Command has been the test bed for an experimental force of long-endurance unmanned systems at sea married with artificial intelligence tools on shore to look for military threats or illegal activity. Unlike some of the high-end drones used by the U.S. military, the information and sensors for each individual system are unclassified, with their output beamed back to a maritime operations center for a human to make a decision when the AI system detects something out of the ordinary. The effort is known as Task Force 59.

We're talking sensor here, not armed units. But these sensors ease the burden on manned units by being out there 24/7 and constantly reporting back to base, at which decision about any action required can be made. The more units out there, the harder for "bad guys" to hide what they're up to.

Innovative Ways to Expand the Radio and Radar Horizon from DARPA

Keep good idea coming (and help design plans for scenarios where satellites might be unavailable) - here is a DARPA test report TALONS Tested on Commissioned U.S. Navy Vessel for First Time:

DARPA’s Towed Airborne Lift of Naval Systems (TALONS) research effort recently demonstrated its prototype of a low-cost, elevated sensor mast aboard a commissioned U.S. Navy vessel for the first time. The crew of USS Zephyr, a 174-foot (53-meter) Cyclone-class patrol coastal ship, evaluated the technology demonstration system over three days near Naval Station Mayport, Florida.

TALONS demonstrated safe and routine operation from the ship’s deck under a variety of sea states and wind conditions without adversely affecting the ship’s operational capability. In tests, the system significantly improved the ship’s ability to detect, track, and classify contacts of interest. It also increased communications range between the ship and remote platforms such as the Zephyr’s rigid hull inflatable boats (RHIBs).

Towed behind boats or ships, TALONS could persistently suspend intelligence, surveillance, reconnaissance (ISR) instruments and communications payloads of up to 150 pounds at altitudes between 500 and 1,500 feet above sea level—many times higher than current ships’ masts—greatly extending the equipment’s range and effectiveness.

“We’re very pleased with the USS Zephyr testing, which showed that a future system based on TALONS could provide operational benefits for even small Navy vessels,” said Scott Littlefield, a program manager in DARPA’s Tactical Technology Office (TTO). “In the next year, we will continue our cooperative relationship with the U.S. Navy and work toward fully automating launch and recovery, which would make the system even easier to use on manned vessels and compatible with unmanned surface vessels.”

“Expectations were really exceeded with the ease of not only deployment, but the recovery of the system,” said Lt. Cmdr. Cameron Ingram, commanding officer of the Zephyr. “Beyond the initial launch, it immediately stabilized, and it had a very smooth transition all the way up to altitude. I was very impressed with how stable it was.”

The TALONS test on USS Zephyr built upon a successful joint test last year with DARPA’s Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV) program. ACTUV’s technology demonstration vessel set sail with TALONS as its first payload as part of open-water testing off the coast of California.

TALONS is part of DARPA’s Phase 1 research for Tern, a joint program between DARPA and the U.S. Navy’s Office of Naval Research (ONR).

That "joint test" with the ACTUV? See below:

DARPA’s Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV) program has developed and built a technology demonstration vessel that is currently undergoing open-water testing off the coast of California and recently set sail with its first payload: a prototype of a low-cost, elevated sensor mast developed through the Agency’s Towed Airborne Lift of Naval Systems (TALONS) research effort.

ACTUV seeks to lay the technical foundation for an entirely new class of ocean-going vessel—one able to traverse thousands of kilometers over the open seas for months at a time, without a single crew member aboard. Potential missions include submarine tracking and countermine activities. Towed behind boats or ships, TALONS could persistently carry intelligence, surveillance, reconnaissance (ISR), and communications payloads of up to 150 pounds between 500 and 1,500 feet in altitude—many times higher than current ships’ masts—and greatly extend the equipment’s range and effectiveness.

The demonstration took place over two days with 90 minutes of flight each day. The TALONS prototype started out from its “nest” installed on the back of the ACTUV vehicle. It then expanded its parachute and rose to an altitude of 1,000 feet, where it tested its onboard sensors and communications equipment. Once the test was complete, the prototype reeled itself in back to the nest. The entire process took place as the ACTUV vehicle maneuvered at operationally realistic speeds.

While aloft, TALONS demonstrated significant improvements to the range of the sensors and radios it carried compared to mounting them directly on a surface vessel. For example, TALONS’ surface-track radar extended its range by 500 percent—six times—compared to its range at sea level. Its electro-optical/infrared scanner doubled its observed discrimination range. The TALONS team plugged in a commercial handheld omnidirectional radio; that radio’s range more than tripled.

“I was delighted to explore the possibility of hosting TALONS on ACTUV and from my perspective, the testing could not have gone better,” said Scott Littlefield, DARPA program manager for ACTUV. “We just started at-sea testing of ACTUV in June, and until now we've been focused on getting the basic ship systems to work. TALONS was our first chance to demonstrate hosting a real payload and showing the versatility of ACTUV to do a wide variety of missions for which it wasn't originally designed.”

“TALONS showed the advantages of using a low-cost add-on elevated sensor to extend the vision and connectivity of a surface asset and ACTUV demonstrated its ability as a flexible and robust payload truck,” said Dan Patt, DARPA program manager for TALONS. “This demonstration was an important milestone in showing how clever use of unmanned systems could cost-effectively provide improved capabilities.”
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Anti-Submarine Warfare in the 21st Century, Sea "Gliders" Division

Or, as the Sam LaGrone USNI News piece is titled, Navy Deploying Unmanned Gilders from Destroyers to Help ASW Mission, and, no, these are not sail plane air craft, but rather mini ships:

The Navy is set to deploy unmanned buoyancy gliders from its guided missile destroyers in an effort to expand its anti-submarine warfare edge.

The service has used the gliders – that use wave action to travel under the water to record information like water temperature and pressure – to build complex models of the ocean depths the service uses as part of its ASW and mine warfare efforts.

Read the USNI News article for more on this promising use of unmanned tech to help expand the Navy's awareness sphere.

Some Good Navy News: Successful Testing of the "Common Control System (CCS)" on Submersible Unmanned Vehicles

We could debate the LCS mess but others are already doing that. See also Pentagon in open brawl over spending priorities.

Far better to look to the Navy's unmanned future, which actually offers the potential to be the lower-cost force multiplier we need. Here's a "good news" article from The Navy League's Seapower magazineNaval Unmanned Systems’ Common Control System Completes First Live Demonstration

The Navy recently tested its newly developed Common Control System (CCS) with a submersible unmanned vehicle during a series of underwater missions at the Naval Undersea Warfare Center Keyport in Puget Sound, Wash., the Naval Air Systems Command announced in a Jan. 22 release.

The CCS successfully demonstrated its capability to provide command and control to a surrogate Large-Displacement Unmanned Undersea Vehicle (LDUUV).

CCS is a software architecture with a common framework, user interface and components that can be integrated on a variety of unmanned systems. It will provide common vehicle management, mission planning and mission management capabilities for the Naval Unmanned Systems (UxS) portfolio.

During the test events Dec. 7-11, operators from Submarine Development Squadron 5 Detachment UUV used CCS to plan and execute several surveillance and intelligence preparation missions. The CCS sent pre-planned missions, via radio link, to the LDUUV’s autonomous controller and displayed actual vehicle status information to the operators during the test. The vehicle was able to maneuver to the target areas and collect imagery.

“These tests proved that operators could use CCS from a single global operations center to plan, command and monitor UUVs on missions located anywhere in the world,” said Capt. Ralph Lee, who oversees the Navy’s CCS program at Patuxent River, Md. “This event also showed us that CCS is adaptable from the UAV [unmanned air vehicle] to UUV missions.”

What? Never heard of CCS?

From USNI News: Pentagon's "Unmanned Integrated Systems Roadmap FY 2013 -2038

"Document: Pentagon's Unmanned Systems Roadmap" from USNI News:

DOD-USRM-2013

U.S. Navy's New Tool? The Unmanned Submarine Follower

Ah, robots!

Faced with high ship building, operating and personnel costs, the U.S. Navy tasks the Defense Advanced Research Project Agency (DARPA) to come up with some help in the hard job of keeping track of quiet diesel- electric submarines for long periods. DARPA has responded with s plan for something called the Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessel (ACTUV). DARPA says:

The program is structured around three primary goals:

1. Explore the performance potential of a surface platform conceived from concept to field demonstration under the premise that a human is never intended to step aboard at any point in its operating cycle. As a result, a new design paradigm emerges with reduced constraints on conventional naval architecture elements such as layout, accessibility, crew support systems, reserve buoyancy and dynamic stability. The objective is to generate a vessel design that exceeds state-of-the art platform performance to provide complete propulsive overmatch against diesel electric submarines at a fraction of their size and cost.
2. Advance unmanned maritime system autonomy to enable independently deploying systems capable of missions spanning thousands of kilometers of range and months of endurance under a sparse remote supervisory control model. This includes autonomous compliance with maritime laws and conventions for safe navigation, autonomous system management for operational reliability, and autonomous interactions with an intelligent adversary.
3. Demonstrate the capability of the ACTUV system to use its unique characteristics to employ non-conventional sensor technologies that achieve robust continuous track of the quietest submarine targets over their entire operating envelope.

So, as reported in the Navy League's Sea Power magazine:

DARPA selected six industry proposals for the ACTUV concept in January 2010 for Phase 1 of the program, the concept definition phase. In August 2012, DARPA selected Science Applications International Corp. (SAIC) to design, construct and demonstrate an ACTUV prototype under the next three phases of the program under a $58 million contract. SAIC “proposed a trimaran platform: key features and innovations for the vessel, sensors, autonomy and
software. The scope of the program includes developing and testing a Remote Supervisory Control System,” Littlefield said.

In March, Raytheon Co. announced that it had been selected by SAIC to provide the sonar system for the ACTUV. The Modular Scalable Sonar System (MS3), a fifth-generation development of the company’s 30-yearold medium-frequency, hull-mounted SQS-56 sonar will have both active and passive acoustic search, detection, passive threat filtering, localization and tracking capabilities. It also will provide torpedo detection and alert and avoidance of small objects.

DARPA ACTUV Simulator Screen Shot

*** The ACTUV’s sonar will need to be autonomous, performing the difficult task of submarine tracking without an operator directing its operation. It will need sophisticated algorithms for automatic tracking, including maintaining a low false-target detection rate. The sonar also will help the ACTUV observe the rules of safe navigation applicable to any vessel at sea.

If this concept works, it will be quite the force enhancer.

UPDATE: DARPA want you to have fun exploring this concept - with its Can You Outsmart an Enemy Submarine Commander? bit, including a chance to run through a simulator.