NAVAL AIR STATION NORTH ISLAND, Calif. – With an eye toward ongoing missile threats to military and commercial shipping, the Navy is moving closer to rearming its surface combatants operating at sea, Navy officials said.
In a proof-of-concept last week using a repurposed 1990s-era prototype equipment, crews transferred and reloaded 25-foot missile canisters between guided-missile cruiser USS Chosin (CG-65) and dry cargo and ammunition ship USNS Washington Chambers (T-AKE-11) off the California coast.
It was the first time the service tested the system at sea. “We are transforming the way the Navy fights,” Navy Secretary Carlos Del Toro said during a Friday press conference after observing the TRAM, or Transferable Reload At-Sea Method, in a replenishment operation for the MK-41 Vertical Launching System while both ships operated.
“Without the ability to rearm at sea, our service combatants must return to port, sometimes thousands of miles away, as we sometimes have to do in the Red Sea,” Del Toro said. “After we shoot the missiles, we have to go back to other ports in order to rearm. The ability to rearm at sea will be critical to any future conflict in the Pacific and elsewhere.”
The Pentagon has stationed Navy ships in the Eastern Mediterranean and the Middle East regions since October 2023 to thwart and respond to missile, drone and boat attacks on merchant vessels, military ships and U.S. allies by Iran-backed Houthi forces. Just earlier this month, the guided-missile destroyers USS Bulkeley (DDG-84) and USS Cole (DDG-67) in the Red Sea fired a dozen “interceptors” against some 200 missiles that Iranian forces launched at Israel, Pentagon officials said. One official told USNI News those included a Standard Missile 3.
Last week’s tests followed earlier in-port transfers of the missile canisters during land-based tests in July at Port Hueneme.
“Up until now, the potential to have working Navy ships at sea was not possible. The demonstration that just occurred offers increased lethality to our war fighters,” Capt. Anthony Holmes, commander of Naval Surface Warfare Center Port Hueneme Division in California, said Friday.
The TRAM concept isn’t new. In the 1990s, engineers at Naval Surface Warfare Center, Port Hueneme Division developed the idea of a prototype to replenish underway warships’ VLS magazines. But coming on the heels of the Gulf War, the prototype was never fully developed, and the system remained warehoused as the perceived need for such at-sea weapons resupply capability had waned, officials said.
“The demand signal wasn’t there for us to need to develop this capability. That has very much changed today,” said Rear Adm. Peter Small, chief engineer and deputy commander of naval systems at Naval Sea Systems Command.
In 2022, Del Toro revived that idea, pushing for the Navy to rearm underway warships. “This is a very complicated experiment,” the secretary said. Early experimentation included reloading two destroyers using a crane and offshore support vessel in San Diego Bay in October 2022.
The TRAM system was refitted for rearming the MK-41 VLS on surface combatants. The VLS system is used to carry and launch a variety of weapons, including the Evolved Sea Sparrow Missile (ESSM), Tomahawk Cruise Missile, Standard Missile 2, Standard Missile 3, and Standard Missile 6, according to Lockheed Martin. But to restock their instrumented test canisters after firing the missiles, warships have to return to port, a transit that can take days or a week or more – depending on the location – and pull combatants out of strike operations for weeks or longer.
“We’ve been keeping the Congress up to date on this experiment,” Del Toro added. “It gives us tremendous pride to now be able to go back to the Congress and demonstrate that this is very much within the realm of implementing over the course of the next two to three years and start bringing them to our destroyers and our cruisers out there through scheduled availabilities.”
The secretary, whose continuing tenure in office depends on the upcoming presidential election results, said he wants TRAM capability deployed across the surface fleet in the next few years.
“A lot of that planning will take place down here over the next few months, and with the support of Congress, we’ll actually have the funds necessary to be able to push this capability out to our entire fleet so that by ‘28, ‘29, by ‘30, we should have this capability on many of our destroyers and cruisers that are operating around the globe,” Del Toro said. “But particularly those that are in the Pacific as well, too, because it has a huge advantage to being able to conduct logistics operations in the Pacific.”
The goal is to deploy TRAM across the force, Small said. “The supply ship itself carries that equipment with it and can then transfer [missiles] to the ship. But the ship has to be configured to receive that equipment to enable this operation,” he said.
The latest tests, led by teams including Naval Sea Systems Command, NSWC Port Hueneme, and NSWC Indian Head, Md., operated the TRAM system in sea states one through three, or up to breezy conditions and up to four-foot waves. At one point, Mother Nature provided a boost for the test teams, with up to 6-foot seas and 20 mph winds in sea state four conditions.
“We had conditions that were at sea state four… and we were able to actually transfer the missile across the ships from the Washington to the Chosin and back very, very safely,” Del Toro said. “So it just was a great sign that the modernization that we made to this capability really has paid off tremendously.”
Small called the final demonstration test “a culmination of a solid year of effort through a great teamwork between the Navy, the Navy labs industry and our university-affiliated research center partners,” which includes Johns Hopkins’ Applied Physics Laboratory.
The tests were done during a typical, connected underway resupply between Chosin and Washington Chambers, using TRAM hardware modified and modernized “with additional sensors and technology,” Small said. Crews used TRAM to remove an empty canister from Chosin’s forward vertical launching cell and then transferred it to Washington Chambers, he said, and then they took a new canister from Washington Chambers and loaded it into an empty VLS cell aboard Chosin.
The nature of the resupply – moving 22- to 25-foot missile canisters between ships in real sea conditions – adds difficulty and limitations to the more routine, side-by-side underway replenishment that Navy ships have done for decades, officials said.
“What was different about a normal replenishment at sea versus one with a loaded missile canister is that the ship’s motions are very important, and the ship’s motions as you travel in a connected way to that canister as it makes the transit across between the ships,” Small said. “The critical part is loading it and unloading the cell out of the vertical launch cell.”
Even on land, there’s very little wiggle room in controlling movement when removing and reloading canisters from the VLS cells – and that’s amplified on a ship in uncontrollable conditions at sea.
“That requires very strict control of a weapon that is loaded into that canister, and that is something that is different than the normal connected replenishment that we demonstrate every day today,” Small said. With sensors and other changes to TAM, “that’s where we added some technology and upgraded that earlier prototype material to be able to have that control.”
While TRAM is a 30-year-old idea, “the technology certainly helps and that’s what allowed us to demonstrate this capability today… (and) about the precision of the exercise and showing the control,” he said. “We collected a tremendous amount of data today, which was really important.”
“That’s going to really inform our next steps going forward as we move to scale this capability and deploy it to both cruisers and destroyers,” Small said. “The data collected throughout the week this week will really tell us how under what [sea state] conditions can we operate the system safely,” he added.
Experts from across NAVSEA’s warfare centers joined in prototyping, rapid experimentation, rapid material design and the development of TRAM for the stresses and conditions at sea, officials said. “We wanted to make sure that given its current condition that we brought it up to the best condition possible for the sea state,” said Timothy Barnard, technology director and deputy chief technology officer at NAVSEA.
Johns Hopkins’ APL teams assisted with data modeling, and while underway, engineer teams joined Chosin crew and sailors with naval expeditionary reload teams. “We were able to really get a lot of insight on how the equipment would behave, define and refine the procedures that we expected to use when we were shipboard,” Barnard said.
NAVSEA teams are poring over the data collected – that includes performance data, movement data, motion data, accelerations and loads – during the demonstration tests, which involved instrumented standard, 25-foot canisters. Follow-on efforts will expand that to look at the entire range of VLS missiles, Barnard told USNI News. “The idea is to have a variety of options to support the force in different conditions,” he said.
Studies are underway to examine integrating TRAM into surface combatants and “looking at design sustainability and maintenance, recognizing that our missiles will continue to evolve and canisters may evolve,” Barnard added, “and positioning TRAM for what we see in the future, and then looking at how to integrate that. So a lot of work still ahead.” That includes getting funding for new prototyping and operational testing at sea for the next phase of TRAM testing, he added.
