They’re used to smuggle drugs into the U.S.
Since the vessels have a low profile—the hulls only rise about a foot above the waterline—they are hard to see from a distance and produce a small radar signature. U.S. counterdrug officials estimate that SPSS are responsible for 32% of all cocaine movement in the transit zone.
But let’s not forget the terrorism angle:
“What worries me [about the SPSS] is if you can move that much cocaine, what else can you put in that semi-submersible. Can you put a weapon of mass destruction in it?” Navy Adm. Jim Stavridis, Commander, U.S. Southern Command