The Kerch Strait bridge connecting Russia with the Crimea is extremely important, both strategically and politically. Stretching for more than ten miles, it is the longest bridge in Europe, and was constructed after Russia’s illegal annexation of Crimea and opened in 2018 at a cost of over $3 billion. Putin himself drove a truck across to open it. It is a huge and obvious target for a Ukrainian strike, and now seems to be under threat with a new doomsday clock supposedly counting down to the bridge’s destruction.
This picture taken on December 23, 2019, shows the Crimean Bridge that spans the Kerch Strait, a ... [+]
The bridge carries both road and rail line. When it was opened, one Ukrainian think tank described it as “Russia’s fingers on the throat of Azov,” and the Russians use it to transport tanks and other military hardware directly to the combat area in the south. To the Russian inhabitants of Crimea the bridge is their lifeline, their connection with the home country; some reports suggest that many are already leaving due to the uncertain military situation.
However, cutting a bridge of this size is quite a challenge. The supports are massive concrete and steel constructions, and attacks on similar bridges show they cannot be brought down by anything less than a direct hit with a massive warhead. The USAF’s choice of weapon for bridge-dropping is a series of guided 2,000-pound bombs, and even then success is not guaranteed, as pilots discovered during the 1991 Gulf War
“I thought that bridges would be pretty easy to knock out with PGMs [precision guided munitions]—until I tried it. We would attack a bridge and get several hits, and then we’d discover—holy mackerel!—the bridge was still standing,” Lt. Dave Giachetti, the 48th Tactical Fighter Wing’s specialist in bridge attacks said in an Air Force Magazine article.
The challenge was to hit a bridge at its weakest spot. If a bomb just hit the roadway, it just left a hole which could be patched up; the only way to drop a span of bridge was to hit abutments at either end.
This sort of bombing mission would be virtually impossible for Ukraine. While their air force is still able to fly, it is only carrying out a few sorties per day, with most of the air power being supplied by drones. Ukraine’s Bayraktar TB2s are taking a heavy toll of Russian vehicles, and even sinking patrol boats and setting an oil facility over the border in Russa ablaze. But the Bayraktar is only the size of a light aircraft and carries a payload of about 400 pounds at most, not nearly enough for the sort of 2,000-pound weapon needed to dent the Kerch Bridge.
"If we had the ability to do it, we would’ve already done it,” said Oleksiy Danilov, Secretary of the National Security and Defense Council of Ukraine, when asked about attacking the Kerch Bridge on April 21. But he did add: “If there is an opportunity to this end, we will definitely do it."
But there are other means besides airpower. And Ukraine may now possess them.
In particular, robotic boats – Uncrewed Surface Vessels or USVs – can be a useful means for carrying out kamikaze attacks. The idea goes way back to 16th century Hellburners, themselves an evolution of old fireships. These made their dramatic entrance during the Spanish siege of Antwerp in 1585, when the Spanish fleet was used to make a blockade across the harbor, the ships packed together to form a pontoon bridge. Italian engineer Giambelli sent three gunpowder-packed Hellburners into the Spanish blockade, with clockwork time fuses; the subsequent explosion sank several ships, killed upward of a thousand Spaniards and shattered the blockade.
A Houthi remote-controlled kamikaze speedboat seen from a Saudi warship
On April 15, Pentagon Press Secretary John Kirby told reporters that the latest package of security assistance to Ukraine would include a number of unspecified USVs but would not give details.
“It’s an unmanned surface vessel (USV) that can be used for a variety of purposes in coastal defense. I think I’ll just leave it at that,” Kirby told reporters. “I’m not gonna promise you a fact sheet [but] I can promise you the damn thing works.”
When asked whether the USVs could be armed, Kirby said “They’re designed to help Ukraine with its coastal defense needs….I’m not going to get into the specific capabilities.”
“Although the USVs could be equipped with explosives and used to carry out kamikaze attacks, I would wonder about the opportunity costs,” analyst Zak Kallenborn — Research Affiliate at the Unconventional Weapons and Technology Division at the National Consortium for the Study of Terrorism and Responses to Terrorism (START) – told me. “I suspect Ukraine would be better served with the technology to convert existing commercial boats for remote operation.”
Kallenborn points to the manned speedboats which Houthi forces have used for attacks on a variety of vessels including a Saudi Frigate back in 2017. In principle a ship of any size can be modified for uncrewed operation; an 1,800-ton cargo vessel recently made a successful 400-mile journey through congested seaways off Japan.
“If the Houthis can do it, why not Ukraine?” asks Kallenborn.
An uncrewed submarine or UUV would be even harder to intercept. There have been no reports of such vessels being supplied to Ukraine at this time, though the U.S. does have a number of large and very large robot submarines under development, such as the U.S. Navy’s Orca XLUUV which might have the ability to emplace explosive charges under a bridge across a strait. Or the job might be done by much smaller craft placing explosives one piece at a time. (Hamas have tried to attack Israeli forces with a small kamikaze robot submarine in 2021).
The countdown to the destruction of the Kerch Strait Bridge is timed to coincide with the start of Russia’s Victory Day celebrations on May 9. A successful attack would be a humiliation for Russia, as well as cutting a vital supply line. In response to Danilov’s comment, Kremlin spokesman Dmitry Peskov warned that an attack on the bridge would bring severe retaliation. Most likely the website is simply an attempt to cause alarm, and perhaps tempt Russia into moving forces to protect the ten-mile length of the bridge from air, sea, or undersea attacks. Or it might be a way of distracting from a possible attack elsewhere, perhaps even in Moscow itself.
The countdown may simply be trolling; trolls have a thing for bridges. But given Ukraine’s previous unexpected successes, such as sinking Russia’s Black Sea flagship, and expanding arsenal of high-tech weapons, there will probably be people in Crimea wondering if they ought to get out now.
UPDATE 7th October: Bridge Downed— The road bridge has just been downed, and rail trucks carry flammable liquid set ablaze closing the rain crossing. Early reports suggest that a truck bomb may have been involved, but some military experts suggest that charges may been have been placed underwater on the bridge supports. However it was done, the demolition is another major blow to Russia and will cause significant logistic problems to the occupying forces.
Updated afternoon 7th Oct: Latest reports show that one lane is still usable by road traffic. Russia says train services will resume soon. However, so may attacks.
