If Ukraine’s ‘Sea Babies’ prevail, the Black Sea could one day become a playground for scuba divers exploring sunken Russian warships. That’s the outlook after Ukraine’s homemade sea drones — remote-controlled power boats packed with a ton of explosives — have sunk more than $1 billion worth of Russian warships.

Now an advisor to President Zelensky, Mykhailo Podolyak, predicts: “Russian warships will eventually take their rightful place, becoming an iconic underwater museum for divers that will attract tourists from all over the world.” A bit over the top, no doubt, but Ukraine’s sea drones are rewriting naval warfare doctrine.

Eighty years ago, United States Navy gunners scanned the skies around Japan’s southern islands for manned kamikaze suicide planes. Today Russian Navy sailors scan the waters of the Black Sea for unmanned kamikaze sea drones. Painted gray and white, the drones are hard to see as they race to a target at 50 miles an hour.

That puts them among the fastest weapons in the seas. “Ukraine’s use of these autonomous vessels is revolutionizing naval warfare,” the author of  “Black Sea Battleground,” Glenn Howard  writes in the Financial Times. A former Jamestown Foundation president, Mr. Howard once saw sea drones as “a technology without a war.”

An underground factory in Ukraine is now fabricating dozens of Sea Babies. In this asymmetric war, Ukraine’s drone navy is pushing back the world’s second largest conventional navy — with  strategic implications, given that Russia’s Black Fleet is responsible for projecting Russian naval power into the Mediterranean.

Russia is supporting the regime of President al-Assad in Syria. However, today, in a retreat to the east, Russia’s Navy is withdrawing its most modern ships from Sevastopol, headquarters for the Black Sea Fleet since 1783. By one count, Sevastopol has been hit 35 times this year by Ukrainian drones and missiles.

Open-source satellite images show that at least 10 major warships have withdrawn to Novorossiysk, Russia’s big port on its Black Sea mainland. With its modern ships now concentrated in the eastern Black Sea, the vessels remaining in Sevastopol, Crimea’s main port, are from the Soviet-era and apparently deemed expendable. 

One day in August, a Sea Baby traveled around the Crimean peninsula and, after a 500-mile voyage, penetrated Novorossiysk.  There, it hit the Olenegorsky Gornyak, a 3,000-ton landing vessel that can carry 10 tanks and 340 troops. Pointed at the air, its anti-aircraft cannons were useless.

“The Sea Baby took 24 hours to get to Novorossiysk,” a retired Ukrainian navy captain,  Andrii Ryzhenko, tells The New York Sun. Referring to long distance communication obstacles, he said: “It was so far away, that the operator several times lost contact.” One week ago, Sea Babies damaged two Russian missile cruisers.

They were the Buyan and the Pavel Derzhavin, which  had  ventured out of Sevastopol harbor. To protect their pricey warships from Ukraine’s $250,000 Sea Babies, Russia is closing harbors with anchored barges and steel nets. Almost half of Russia’s Black Sea Fleet’s 40 major surface ships have been damaged or sunk.

However, the fleet is down, but not out. Of the fleet’s five Kilo-class diesel-electric submarines in the Black Sea at the start of the war, four remain. One, the Rostov-on-Don, was destroyed in Sevastopol on September 13 in a missile strike that also took out a landing craft and the Black Sea fleet’s only dry dock in Crimea.

Competing with Russian subs, Ukraine showed off last month a 20-foot long, $433,000 underwater drone. Called the Marichka, these drones can carry 500-pound warheads and range 600 miles. They will be attached to the Ukrainian Navy’s new drone unit, the 385th Separate Brigade. 

Some of Russia’s subs and missile carrier ships now in Novorossiysk can fire Kalibr missiles. These have a range of 1,500 miles, but cost $1 million apiece. In a counter move, America supplied Ukraine last month with Army Tactical Missile Systems. These missiles now put all of Crimea within missile range of government-controlled Ukraine.

A week ago, the Dutch prime minister, Mark Rutte, visited Odessa and promised more air defense missiles to protect the Black Sea port city from Russian missile attacks. He told reporters: “This winter, Russia will try to hurt Ukraine as much as possible. So, the Netherlands will supply extra Patriot missiles so that Ukraine can defend itself against Russia’s barbaric airstrikes.”

With Russia’s Navy increasingly restricted to port, Ukraine has opened a corridor for grain ships to pass from its Odessa ports to the Bosphorus, the Turkish strait connecting the Black Sea and the Mediterranean. Over the last month, 32 ships have used this channel, hugging the coast until they reach the waters of three NATO nations — Romania, Bulgaria and Turkey. Captain Ryzhenko, who now works for the defense and logistics consultant firm Sonata, says: “The grain corridor is working.”

For Odessa, Ukrainian drones and missiles have pushed the Russian Navy at least 125 miles offshore — a far cry from the early days of the invasion when Russian warships were visible from the city’s beaches. A retired U.S. Marine Corps colonel, Andrew Bain, based in Ukraine, tells the Sun from Odessa: “Odessa is beautiful right now. The beaches were open all summer. There are lots of tourists. I am shopping around for an apartment. We went to the ballet Saturday.”

Captain Ryzhenko says that drones alone cannot carry the day. He advocates a “mosquito navy” — a fleet of fast, well-armed boats to patrol Ukrainian waters in the Black Sea and adjoining Azov Sea. He says: “The primary task of the Navy is sea control and sea denial in littoral waters.  Drones are unable to implement this mission.  Maritime drones, Sea Babies, and others are very good supplements to a mosquito fleet.”

Bitten by mosquitoes or blown up by drones, the future does not look good for Russia in the western Black Sea. Twenty-first century Russia seems to face a throwback to the start of recorded time. Then, ancient Greeks called the Black Sea “the Inhospitable Sea.” They complained of hostile tribes that inhabited its shores.