When it comes to future wars, it does not matter how great U.S. weapon systems are if the services cannot use them at the appropriate time. Admiral Raymond Spruance recognized this during World War II. His attack plan was vastly undercut by how far ships would have to sail to restock ammunition. U.S. aircraft carriers had a 1:4 ratio of how long they could stay in the fight compared with how long they needed to restock their ammunition, which equated to being in combat 6 out of every 30 days, with the other 24 spent sailing back and forth to Ulithi Atoll.1 While the port played a significant operational role in the Pacific war because of its calm water and location, it was not close enough for Admiral Spruance’s objectives.
How can the United States refuel and restock it ships faster in times of war? Developing better weapons is an important task, but that lends itself only to tactical naval power—ammo is depleted and then ships retreat as they have nothing left with which to defend themselves. If there is little to no focus on the operational logistics of a weapon system, then its value is undercut from the start. In the words of Jeffrey Cares and Antony Cowden in their book Fighting the Fleet, “Logistics IS naval power.” The Navy creates more problems for itself than it solves by not focusing on the logistical aspect. New weapons may be shiny additions to the arsenal, but without logistics they will be not much more than ineffective new gizmos that cannot be used often, if ever. The service cannot afford to develop such weapons considering how much research and development goes into new military technology.
To close the gap between tactical naval power and operational naval power, there must be a focus on rearmament at sea. Secretary of the Navy Carlos Del Toro has defined this as one of his priorities.2 Arleigh Burke–class guided-missile destroyers are regarded as one of the most successful classes the Navy has ever built, but they have their limitations. If a destroyer is out of missiles after two days, she needs to sail to the nearest port to restock ammunition. This is valuable time lost. In the Pacific, it can take up to two weeks to travel to port to rearm, three if a ship reloads at San Diego. This warfighting-to-rearming ratio is at best 1:6, even worse than the aircraft carriers in World War II.
Yet, rearmament at sea remains a difficult problem. Even though the Navy has figured out ways to improve basic underway replenishment (UnRep) procedures using a standard tensioned replenishment alongside method (STREAM) and now E(electric)STREAM, missile replenishment is a much different challenge.3
First, missile canisters can be enormous. They are 25-feet tall for the strike module and 22-feet tall for the tactical module.4 They also need to be vertically loaded straight onto the ship. In addition, the Navy does not want to lose any missiles. There are times during an UnRep when a ship has to cut the line because she is not going the right speed or is not a safe distance away or if there is an emergency. While it can be frustrating, only mail has been dropped in the sea, and the losses are acceptable. With each missile costing at least a million dollars, losing even one is much less acceptable, not even factoring in any damage that might happen to the ship if something goes awry.5 There is a larger margin of error admissible during a regular UnRep, but not during rearmament for reasons such as safety and money.
Special equipment is also needed to put missiles on destroyers. Reloading vertical launch systems (VLSs) has always occurred in port, partially because of the equipment. Even then, not every Navy port is equipped for this function.6 The crane is the limiting factor, as it needs to be strong enough to lift the canisters and close enough to transfer them. Reloading VLSs also happens in port because of weather conditions, namely, sea state and wind. Reloading missiles even in calm waters has proven tricky.7
The Navy currently is testing equipment to enable it to rearm at sea. The Naval Surface Warfare Center designed the Transferable Re-Arming Mechanism (TRAM) to enable VLS reloading in conditions up to Sea State 5 using an articulated crane that can vertically lift and rotate a missile canister and then lower it into a cell.8 There have been a total of three demonstrations of the TRAM.
Of the three demonstrations, which were performed in conjunction with Military Sealift Command (MSC), the first two were successful, but the third demonstration, in which a canister was transferred at anchorage, was unsuccessful. The equipment was not the problem, but rather the excessive movement of each ship. It was not safe to have sailors on deck to guide the missile into its cell, and the crane arm swung too much for it to complete the transfer.9 Secretary Del Toro has instructed the service to begin testing TRAM at sea this year, but the process is not moving fast enough.
TRAM may eventually allow the Navy to rearm at anchorage, and maybe even while underway. However, there is another problem. During a conflict, how will these supply ships protect themselves? MSC ships do not have the self-defense armament of warships. Even though the law of armed conflict protects MSC ships, belligerents may not respect that protection. In such cases, different options will need to be considered.
One option could be to arm MSC ships. Then, however, would they be considered warships? How much firepower could they have and would the sailors on board be considered combatants? Another option would be to use ships currently in the fleet.
While the main purpose of the dock landing ship (LSD) is to transport landing craft air cushion (LCACs), there is no reason the Navy could not use them to rearm destroyers with missiles.10 LSDs would still be able to service LCACs, which are stored in the well deck, so the specialized crane would not take space away from them. The crane would, however, take away some space on the fantail, and with it the ability to fly and land helicopters. But this would be a necessary sacrifice. In addition, LSDs have the benefit of already being armed. Both the Harpers Ferry and Whidbey Island classes have two 25-mm Mk 38 machine guns, two 20-mm Phalanx close-in weapon systems, six .50-caliber machine guns, and two Rolling Airframe Missile mounts.
Integrating the Dynamic Positioning System (DPS) on ships also could help solve this problem. This is more for future DDGs, but DPS allows ships to automatically maintain heading and positioning without setting anchor.11 DPS technology has been implemented on commercial ships since the 1960s. On Navy ships, it would allow more sailors to focus on transferring missiles and ultimately spend less time out of the fight.
Achieving the ability to rearm VLS at sea would give the Navy a significant advantage in future conflicts. Even being able to reload at anchorage in a moderate sea state would be a crucial improvement. Admiral Spruance found a solution that cut his rearmament time from 12 days to 2—by using existing cargo winches on both the delivery ship and aircraft carrier to transfer ammuntion and supplies between them while steaming alongside.12 Today’s Navy will find a solution to achieve something similar. What that solution looks like, only time will tell.
(This article originally appeared in the print edition under the headline "Improving At-Sea Missile Rearming.")
1. CDR John A. Lukacs IV, USN, “Century of Replenishment at Sea,” Naval History 32, no. 3 (June 2018).
2. Megan Eckstein, “U.S. Navy Prioritizes ‘Game-Changing’ Rearming Capability for Ships,” DefenseNews, 28 March 2023.
3. CDR John A. Lukacs IV, USN, “The Value of (UnRep) Time,” U.S. Naval Institute Proceedings 144, no. 1 (January 2018).
4. Lockheed Martin, “MK41 Vertical Launching System.”
5. Tyler Rogoway and Joseph Trevithick, “Here Is What Each of the Navy’s Ship-Launched Missiles Costs,” The War Zone, 11 December 2020.
6. LCDR Tom Granger, USN (Ret.), “Reload Missile Shooters at Sea,” U.S. Naval Institute Proceedings 144, no. 7 (July 2018).
7. CDR Douglas Robb, USN, “Reload Vertical Missile Tubes at Sea Is Within a Crane Arm’s Reach,” DefenseNews, 4 December 2023.
8. Richard Scott, “U.S. Navy Set to Trial VLS Reloading System at Sea,” Naval News, 19 February 2024.
9. Gidget Fuentes, “Navy Tests Reloading Missiles on Destroyer in San Diego Bay, Open Ocean Tests Tougher Task,” USNI News, 18 October 2022.
10. U.S. Navy, “Dock Landing Ship–LSD,” 19 July 2019.
11. U.S. Coast Guard National Center of Expertise Outer Continental Shelf, Introduction to Dynamic Positioning (DP) Systems (Washington, DC: Headquarters, U.S. Coast Guard, 2019); and Robb, “Reload Vertical Missile Tubes at Sea.”
12. Lukacs “Century of Replenishment at Sea.”
