Dr. Scott Savitz first appeared on Naval News for his December 2022 RAND commentary on “The Threat of Drifting Mines.”
In 2022 and 2023, Dr. Savitz wrote a few RAND commentaries on the advantages and usage of unmanned surface vessels (USVs) and kamikaze USVs.
As Dr. Savitz mentioned in his November 15, 2022 “The Age of Uncrewed Surface Vessels” RAND commentary, he wrote, “There are two reasons why USVs can be much more dangerous to ships than aerial weapons: where they strike and the scale of their explosive payloads. A USV, however, strikes at the waterline, and can carry a larger payload than a vehicle that needs to be flown through the air. Such an attack can damage critical portions of the ship well below the superstructure, such as engines and munition-storage areas, potentially causing secondary detonations.”
In his October 20, 2022 “Beware the Explosive Vessels” RAND commentary, he wrote, “Divers’ payloads are inherently limited, so having them plant enough explosives to damage the bridge would have required numerous clandestine trips. Uncrewed undersea vehicles (UUVs) could conceivably have been used, but readily available UUVs have limited payloads and ranges.”
In his January 9, 2023 “Could Taiwan Defend with Uncrewed Surface Vessels?” RAND commentary, he wrote, “By striking at the waterline with larger payloads than comparably sized missiles or uncrewed aircraft, USVs can potentially inflict devastating damage. Swarms of low-profile USVs approaching rapidly from multiple angles can be difficult to detect, track, and target effectively. One or two getting through would constitute success.”
Intrigued by Dr. Savitz’s commentary on USVs used for one-way explosive laden trips, Naval News emailed the Senior RAND engineer a questionnaire on August 19, 2023 in which he answered promptly.
Naval News: How can kamikaze USVs defend an island nation that no other weapon system can such as naval mines, warships, anti-ship missiles, or submarines?
None of these will do it alone, and other platforms (including ground forces) will also contribute. These USVs complement the others, contributing to attrition of adversary forces and disruption of plans. Incidentally, USVs used for other purposes, such as intelligence/surveillance/reconnaissance or mine countermeasures, can also play a role. So can uncrewed systems in other domains.
Naval News: We’re into the “quantity over quality” issue with kamikaze USV swarms, and yet kamikaze USVs seem to be getting more complex, expensive, and sophisticated. How can kamikaze USVs contribute to the overall defense of an island nation without absorbing too much cost and budget?
They don’t need to be very expensive; Ukraine has repeatedly said that each of its USVs costs about $250,000. Acquiring a thousand similar ones would cost just over 1% of what Taiwan currently spends on defense annually. That’s equivalent to about three F-35s, but with maintenance, support, and training costs that are multiple orders of magnitude lower.
While acquisition processes can readily result in cost escalation, that doesn’t need to happen with good program management and sufficient competition.
Naval News: Wouldn’t kamikaze USVs interfere with other defensive naval operations such as mining, sonar, submarines, barricades, intelligence, surveillance, reconnaissance (ISR), and deception?
All military operations require deconfliction. In this case, deployment of minefields or blockships (see https://www.usni.org/magazines/proceedings/2021/december/blockship-tactics-trap-enemy-fleets) would be synergistic with the use of explosive USVs: constraining and slowing the movements of ships makes them more vulnerable to USV attack. Swarms of small USVs can dance freely through a minefield to strike a larger ship that is struggling to adhere to a narrow lane. Even before that, explosive USVs could target the inherently fragile mine countermeasures vessels attempting to clear lanes, thwarting the operation–see https://www.usni.org/magazines/proceedings/2022/april/imperative-defend-minefields.
Naval News: Why kamikaze USVs? Wouldn’t it be easier to arm USVs with long-range weapons and have them attack enemy warships instead of ramming them?
Larger USVs can also launch torpedoes or missiles, and their use for that purpose complements the use of smaller, low-profile, explosive USVs. Torpedoes and missiles are more expensive, while the latter are less likely to inflict severe damage than something that strikes at or below the waterline, like a torpedo or explosive USV. Expendable, low-profile explosive USVs also have greater range and can approach or lurk in the vicinity of targets, waiting for the moment to strike, in environments where a larger USV that launched weapons would likely be targeted. Both weapon-launching and explosive USVs can be useful in the right contexts.
Naval News: We heard of the “Mosquito Fleet” as some potentially being somewhat ineffective throughout history. How do kamikaze USVs differ from a Mosquito Fleet?
The “mosquito fleet” of PT boats in World War II inflicted a lot of damage using torpedoes; I wouldn’t call it ineffective. The mechanism of attack was different from explosive USVs, but again, torpedoes are also useful.
Naval News: Are kamikaze USVs a phase or fad until the invention of cheap UAVs, flying cars, and electric powered aircraft? Or are we onto some greater revolution in naval warfare?They’re not a fad. Inflicting damage on durable targets like bridges or large, well-built warships takes a lot of explosives, and attacks at or below the waterline are most effective. That’s why the Kerch Strait Bridge was damaged at least once, and probably more, by explosive USVs.
Naval News: There has been much hype about gigantic “killer city” nuclear torpedoes. Wouldn’t that be a more effective anti-ship weapon than swarms of kamikaze USVs?
Putin claims that he has trans-oceanic torpedoes/UUVs that contain nuclear weapons to destroy cities. While nuclear weapons can be devastating, their usage is constrained through deterrence. More pertinently, Russia is lying about this. See my comments in https://www.jpost.com/international/article-719118.
“Tottering dictatorships, like James Bond villains, often tout supposed superweapons as a refuge from their fears,” said Savitz, a Senior engineer at the Rand Corporation. Savitz told the Post that Russian weapons technology, like its military prowess, is often oversold. He said that the autonomous capabilities, range and speed attributed to the Poseidon by Russian sources sound highly implausible. The Rand engineer gave an example of another maritime technology that Russian military officials have been touting. Savitz said that for over two decades, Russia has been claiming that it possesses supercavitation technology, which creates a blanket of gas around a torpedo so that it can glide through the water without any drag. This would create faster torpedoes than those commonly used by Western navies. However, this weapon hasn’t been seen in operation.” — Scott Savitz quoted from “Here’s Why You Shouldn’t Fear Russia’s Poseidon Nuclear Torpedo” by Michael Starr, October 7, 2022, The Jerusalem Post
Naval News: With GPS jamming, smokescreens, spoofing, and close-in weapons systems (CIWS), how effective do you believe kamikaze USVs will be in the future?
Electromagnetic and other interference will undoubtedly be used to counter them, as will CIWS and other weapons. A high-signature target like a bridge or ship, though, can still be hit. Detection will remain hard, sheer numbers can overwhelm defenses, and shooting from near-vertical angles is tough.
A standard cycle of countermeasures and counter-countermeasures doesn’t invalidate the ability of a system to have a powerful impact. To summarize a similar cycle over the last century, the rise of military aircraft was matched by ground-based and ship-based air defenses and radar, then there was radar jamming and stealth, as well as lots of attempts to gain an edge. Aircraft remain relevant.
Naval News: What tactics, techniques, and procedures would you use kamikaze USVs against? Are these USVs for low, medium, or high-value targets? Should a nation have cheap, medium, and expensive USVs or better to keep it simple and just have one type?
The USV should be designed for the potential mission(s); Ukraine, Taiwan, and the U.S. all have different mixes of needs, which may vary over time. This question is a good subject for an expansive RAND study.
Naval News: Would kamikaze USVs ever be dangerous enough to sink large warships, or are kamikaze USVs only good for damaging and slowing down large ships?
Multiple hits with substantial amounts of explosive could severely damage even a very large ship, and depending on the damage-control capabilities of the ship and its crew, it could sink. Precisely modeling the effects of given quantities of explosive hitting a specific class of ship in particular locations would require extensive classified analysis. Incidentally, bridges are generally quite durable, and are designed to withstand a lot of force, so the impact of the USVs on the Kerch Strait Bridge is impressive.
Dr. Savitz offers some final thoughts in his “Could Taiwan Defend with Uncrewed Surface Vessels?” commentary.
“Explosive USVs by themselves, or used in tandem with naval minefields, probably could not defeat an incoming PLAN fleet. However, they could inflict large-scale damage as that fleet progressed across the Taiwan Strait, alongside anti-ship missiles, air-dropped bombs, and other weapons. By elevating the risk to an invasion fleet, and possibly reducing the capacity of an invasion force, an array of inexpensive USVs could menace the PLAN enough to deter the Chinese Communist Party from invading Taiwan.”
Dr. Scott Savitz, RAND Corporation’s Senior Engineer