Russia sank ships to protect a key bridge from Ukraine's naval drones. It might not be enough to keep the small exploding vessels from hitting their targets.

• Russia is sinking ships to protect the Kerch Bridge to Crimea from Ukraine's naval drones.
• But small, smart exploding vessels could still navigate the barrier and hit their target.
• Ukraine's fleet of waterborne drones has terrorized the Black Sea, hitting ships and supply lines.

With Ukraine's small but mighty naval drones terrorizing Russian assets in the Black Sea, Russia has resorted to sinking old ships to create a protective barrier for its key Kerch Bridge to occupied Crimea.

But the defensive line of wrecked ferries and ship barges is far from a catch-all solution, an expert told Insider; it could just be a Band-Aid on a bullet hole.