They had a solution way back in the day for any kind of "submersible" on the surface, whether it able to completely submerge or not. Depth charges and deck guns! It'll definitely submerge then!
Here is a question. I assume many of these subs are being missed, and they make it to the US. Who picks this crap up? I doubt a sub is pulling into the Port of Miami.
I guess the point I am trying to make is why doesnt the Navy and USCG monitor these subs and then take down the whole operation once they are at the transfer point. Guess I never understood the logic of taking them out in open seas when someone in the US was set to transport a few tons of Coke into the Country.
Hmmm.... Interesting idea, but I think the devil would be in the details (said the non-operational guy!). You know, probably better than I, how unpredictable things at see can be.
I suspect the overall approach is one of "Bird in hand is better than two in the bush".