Navy Matters has an excellent piece on using small ships as part of a fleet.
I think its absolutely essential to remember there are some key words there, "as part of a fleet".
A fleet of 2000 to 3000 ton frigates is going to be annihilated by a 10,000t destroyer, just because it is going to see them first through a higher mounted radar.
However, if we have a ten thousand ton destroyer and a few 3000 frigates, the Destroyer can sail around with its radar blaring, and the targets acquired can be fed to the silent frigates, who are around the destroyer.
Anyone who tries to attack the destroyer gets a nasty surprise, and the frigates can run and hide behind their big brother in a sustained engagement.
I posited the idea of ship carrying an unmanned CB90 armed with NSM, probably impactical, however, the Skjold Class is already cleared for firing the missile.
An umanned Skjold Class with 4/8 NSMs would be an exciting tool, a fleet towing 8 of them would have frightening amount of options.
Imagine a modern Jutland type scenario.
The Enemy fleet turns in defeat, do you pursue? And risk running over 8 unmanned stealthish ships carrying 64 AShMs? Or do you let the enemy fleet escape and live to fight again another day?
Or, You are defeated, you turn to run, dropping mines, laying smoke and chaff, the enemy runs 8 unmanned (so suicide) ships through, 4 are lost, the other four unleash hell on the rear of your retreating ships, a third of your capital ships are damaged and lack the speed to escape. Do you resume hostilities? Or abandon a third of your fleet?
Nothing remotely difficult about dropping them off and telling them to wait an hour and then catch up.
Or the Falklands.
Imagine landing at San Carlos knowing 8 of those are prowling?
Sanitise the area?
With a top speed of 75kmh and a range of 185km, clearing the top zone gets you four hours.
Forcing them back to port gets you SEVEN hours.
Fancy landing your liberation force with those sat in port? A frightening fleet in being.
How do you react to a vessel like that? Its virtually invisible, its fast on a level the navy isnt geared up to consider, its sustainable to a level they arent either, dropped off, or self deployed, it can run a single diesel engine for, who knows, weeks?