SNEB
Going back to the SNEB rockets, I would question how useful they would be against shipping. As a Canberra pilot in the 1960s I trained with these weapons. I understood that they were for personnel and soft skin vehicles. That would have been with the HE head.
The alternative was a shaped charge head, but I think it was only good for 2" armour. A full pod of these would clearly make a mess on upper parts of a ship, but I would have been surprised if the ship was crippled as a result.
Because SNEB missiles were carried in tubes, the head had only the diameter of the rocket - 68mm I think.
In WWII, Coastal forces used rockets to sink small ships. Those were 3" rockets, so 76mm diameter, but the AP heads were of a greater diameter and therefore heavy. The trick was to place them below the vessel's waterline to cause flooding. Then the head was solid-shot and could achieve this, while the SNEB shaped charge would ejaculate on impact with the water. 3" RP were obsolete in the 1960s, no doubt because they caused so much drag, but I could visualise them as useful weapons on the A-10.