Say that the intel services say that every small craft is having missiles loaded onto it. What do you do then? Shoot every boat on sight, civilian or military, on the theory that it might have a cruise missile on board?
Many of these boats don't even show up on radar. They're not a big enough target for you to hit with missiles. Even if you could, the missile costs more than the boat. So you'd need to dispatch a destroyer or a bunch of aircraft to strafe it with gunfire.
But then you leave your destroyers/aircraft open to counterattack from small boats. At $30k a boat and $500k a cruise missile, how many of them do you have to sink to equal a $100M aircraft or a $1B destroyer?
Incidentally, Japan had a similar plan for defense of the home islands in WW2. They produced nearly 6000 Shinyo, suicide motorboats with a crew of one and a massive explosive in the bow. As the American invasion fleet entered home waters, the plan was for these to swarm the fleet and blow up as many vessels as possible. I suspect this is a major reason why we dropped the A-bomb instead of going forward with an invasion of the Japanese home islands.
There was a proposal to build lots of fast, highly maneuverable catamaran vessels using stealth technology and armed with cruise missiles. If I was China, I'd be building a few squadrons of those things. (You could even have them leave the missile behind in the water, to pop up and launch itself towards the group at a predetermined time, making it much harder to find the launch platform.)
Many of these boats don't even show up on radar. They're not a big enough target for you to hit with missiles. Even if you could, the missile costs more than the boat. So you'd need to dispatch a destroyer or a bunch of aircraft to strafe it with gunfire.
But then you leave your destroyers/aircraft open to counterattack from small boats. At $30k a boat and $500k a cruise missile, how many of them do you have to sink to equal a $100M aircraft or a $1B destroyer?
Incidentally, Japan had a similar plan for defense of the home islands in WW2. They produced nearly 6000 Shinyo, suicide motorboats with a crew of one and a massive explosive in the bow. As the American invasion fleet entered home waters, the plan was for these to swarm the fleet and blow up as many vessels as possible. I suspect this is a major reason why we dropped the A-bomb instead of going forward with an invasion of the Japanese home islands.