As documented in Operation Kronstadt, The head of the British Secret Intelligence Service, Captain Mansfield Cumming, wanted to use Coastal Motor Boats to rescue a field agent out of Bolshevik-controlled Petrograd in 1919. The CMBs were small and fast, and had the ability to hydroplane and avoid the sub-surface mines used to defend the harbor.
But that was not the original purpose of the CMBs, which was to be battleship-killers.
That purpose was nevertheless fulfilled by the CMBs, as the junior naval officer selected to lead the secret mission by ‘C’, Lt. Gus Agar, decided to use a CMB under his command to attempt to relieve the coastal fortress at Krasnaya Gorka which was being reduced by Oleg and other Bolshevik ships.
In a way, each bit of military technology here was used to its intended effect. The Oleg was a cruiser rather than a battleship per se, but it was effective at avoiding the stationary guns of Krasnaya Gorka and breaking down the fort’s defenses so it could be assaulted by land. The CMB was too small and fast for the Oleg to defend itself, and was sunk in turn, although not soon enough to rescue the Ingrians in the fort who had rebelled against the Bolsheviks, and were massacred once the walls were breached.
This impromptu assualt by a junior officer that didn’t have much to do with his mission was impressive enough to earn Agar a Victoria Cross, and the Admiral in charge of the Baltic Fleet decided to raid Kronstadt harbor with a bigger, better supported force later that same year. The amount of destruction dealt out by the CMBs was perhaps less than you might have expected from Agar’s assault run, but it was good enough to give the British Fleet a strong advantage in the Baltic.
The technological frontier for this kind of military technology has been remarkably stable for the last hundred years or so. Battleships were eventually displaced by aircraft carriers, although you’ll find some interesting counter-points in the Twitter thread that started this. One hundred years ago, small fast boats were designed to counter powerful ships, yet the powerful ships didn’t simply go away. Now, small fast missiles are designed to counter powerful ships, and the powerful ships haven’t gone away.