When the Biden administration announced a new package of military aid for Ukraine this week, the highlight was an additional shipment of long-range, mobile rocket launchers capable of hitting targets deep behind enemy lines.
But there was also some less-high-tech military equipment on the list that may prove just as important to any effort to recapture the city of Kherson in the south: 18 boats.
Control of waterways could be crucial in a looming counteroffensive in the Kherson region, which is bisected by the Dnipro, a river that runs through the country in a giant S-bend from the border with Belarus to the Black Sea.
Ukrainian forces this week used long-range missiles to pound the Antonivsky bridge, which traverses the river, seeking to prevent Moscow from resupplying its troops in the city of Kherson from its bases further south in the Crimea region. The strikes caused damage, according to video posted by a senior Ukrainian official, and while the bridge appeared to remain passable, the attack demonstrated that it is difficult to defend.
“Things can happen,” said an adviser to Ukraine’s president, Anton Gerashchenko, in a post on Twitter. He said the strikes had been conducted by High Mobility Artillery Rocket Systems, or HIMARS, weapons that have been supplied by the Biden administration and are included in the new aid package. A Ukrainian official with the Kherson regional administration, Yuri Sobolevsky said on Friday that, in the wake of the attack, Russian forces were now planning to build a pontoon bridge across the river.
Almost all of the territory Russia has captured in Ukraine since February lies east of the Dnieper, but Kherson, a port and center for shipbuilding, is on the western bank, making it vulnerable. The city fell to Moscow in March, in part because, in an act deemed by some Ukrainians as treachery, the local authorities did not follow through on plans to blow up the bridge, allowing Russian soldiers to roll into the city.
“If the Ukrainians can damage or close it, it will weaken the state of the Russian defense, and Kherson will be more and more difficult to supply,” said Ben Barry, a senior fellow at the International Institute for Strategic Studies, a research group based in London.
“Supplies can be flown in by helicopter or fixed-wing aircraft, but these are more vulnerable to Ukrainian antiaircraft missiles and it’s expensive in terms of fuel,” Mr. Barry said.
Ukraine’s biggest battles, such as the fight for the capital, Kyiv, and the campaign in the eastern Donbas region, have been fought on land, but control of water remains a crucial theater of the conflict. Russia’s navy has, since 2014, dominated the Black Sea, threatening the city of Odesa and preventing Ukraine from exporting grain and other goods.
Missiles supplied by the United States sank the pride of Russia’s Black Sea fleet, the Moskva, in April, and they also helped Ukraine recapture Snake Island, off the coast of Odesa, last month. Both acts set back Russia’s naval dominance.
The Biden administration last month said it would supply 18 patrol boats to help Ukraine protect its rivers and coastal waters. Mr. Barry said these could also help to facilitate river crossings by Ukrainian forces — a delicate maneuver. Russia suffered one of its most painful defeats in May when a battalion was decimated as it attempted to cross a river in the Donbas region that is much narrower than the Dnipro.
President Volodymyr Zelensky of Ukraine said in an overnight address that the country had “a significant potential for the advance of our forces on the front.” He did not detail where those gains might come, but neutralizing Kherson’s bridge appears to be a prerequisite in the south.