Ukraine's navy is harassing Russian forces with 16 new armored assault boats built by Sweden

Steel Front, a military assistance initiative run by Ukrainian billionaire Rinat Akhmetov, sent Ukraine the new CB90-class fast assault crafts, which are already in operation in waters near Crimea.

Following a six-month effort by Steel Front and Ukrainian steel giant Metinvest, the three vessels and crew training for Ukrainian forces cost more than $4.1 million.

"There is no doubt the Black Sea is an important front," Oleksandr Vodoviz, an executive at Metinvest, said in a statement, "and our aim is that these powerful boats will make a significant difference to Ukraine's ability to defend itself."

In total, Sweden has provided at least 13 CB90s to Ukraine's navy. The Netherlands donated nearly two dozen inflatable and armored boats, including three CB90s, to Ukraine in March. The Finnish Ministry of Defense also delivered a number of landing crafts to Ukraine. It wasn't immediately clear what type of vessels were sent, but Finnish media speculated them to operate similarly to the Swedish CB-90.

Dockstavarvet, a shipyard owned by Swedish defense manufacturer Saab, originally developed the CB90 for the Swedish Navy.

The 52-foot-long patrol boat is propelled by twin diesel engines that allow it to travel at speeds of up to 40 knots — or 46 miles per hour — with a range of more than 240 nautical miles.

Two partially ducted water jets make the lightweight CB90 highly maneuverable. It can make sharp turns and come to a complete stop in about 130 feet.

The combat boat is equipped with a gun mount atop its wheelhouse, which can mount a .50-caliber machine gun, 40mm grenade launcher, or remote-controlled weapons.

In addition to its top-mounted guns, the CB90 can deploy Hellfire anti-ship missiles, 2.8-ton sea mines, and depth charges.

Designed to patrol and defend coastal waters, the shallow-draught CB90 can be deployed in both open waters and rocky shores for missions like ferrying troops, mine reconnaissance, or landing troops for amphibious raids.

The vessel's aft is also configurable; it can accommodate a range of gear, from remote-controlled weaponry to additional radar and communications equipment.

Whether operating as a combat-ready gunboat or a floating command post, the CB90 has a durable hull made of lightweight polyethylene lining and safety glass, offering ballistic protection to shield its personnel and vital components during hostile operations.

"With its armament and ballistic protection, the CB90 can deliver its troops in the face of enemy fire with a degree of survivability for both the craft and embarked troops," Pete Pagano, a retired US Navy officer, wrote in an article for the US Naval Institute's Proceedings magazine.

While the armed and armored CB90 can survive the potentially high-risk delivery, Pagano wrote that the Swedish-built vessel alone "could provide limited supporting firepower for the embarked troops during the vulnerable approach to and landing on the beach," calling for support from other landing craft to bring in heavy equipment.

The boat is typically operated by a crew of two officers and one engineer, with two operator seats and a middle jump seat in an aircraft-style cockpit.

The CB90's midsection has a compartment that can carry 21 combat-ready Marines and up to 4.5 tons of cargo, making it an efficient method to deploy troops or extract casualties.

Since being commissioned in 1991, more than 200 CB90 boats have been operated by naval forces worldwide. The US Navy even contracted US-based boat manufacturer SAFE Boats International to build CB90s as riverine command boats.

The combat boat's design and capabilities have also been modified over the years. Dockstavarvet optimized the boat's design in its next-generation variant, the CB90 HSM, altering the engine position to make it quieter and more efficient.

The CB90 HSM features a new combat management system and surveillance sensors, making it "a whole new breed, ready to take on the coasts of Sweden," according to a press release.

While the new combat boats are operating near Crimea, CB90 boats supplied by Ukrainian allies have bolstered the country's riverine units, which have been hammered by Russian forces.

Explosive-laden Russian drones and artillery have decimated Ukrainian boat crews defending the Dnipro River in southern Ukraine.

Last October, a Russian ace drone pilot, identified by the call sign "Moisey," struck nearly 400 Ukrainian marines and three dozen vessels.

"We were sitting in the water at night, and we were shelled by everything," a Ukrainian marine named Maksym, who was stationed at the river's east bank, told The New York Times in December. "My comrades were dying in front of my eyes."

Maksym added that Russian aircraft continued to pummel the left bank with glide bombs as the Ukrainian platoon tried to evacuate.

"The left bank was like purgatory," he said. "You are not dead yet, but you don't feel alive."

The Swedish CB90s, among additional donated boats from other allied nations, have been integral to Ukraine's efforts to fend off Russian forces in the region.