Submarine narcotraficante style.
From an article by H I Sutton at the "Covert Shores" Internet web site. The total package, the soup to nuts authoritative source for drug smuggler submarine operations.
"Narco Subs 101"
"Nacro submarines are increasingly sophisticated with mature designs now focusing on Low-Profile vessels and Snorkel-subs, a sub-category of semi-submersibles."
A semi-submersible low-profile drug smuggler boat. Click on image to see an enlarged view.
That array of narco-subs quite amazing, numbers and types bewildering even. Each design more sophisticated that the previous. A lot of time and money spent by the drug smugglers. But they do have deep pockets. As to the varieties of submersibles consider:
(This info is from a former USN Officer and Nacro-sub expert... ).
Type 1: "Fully Submersible"
Type 1B: "Towed 'Torpedo"
Type 2: "Semi-submersibles"
Type 3: "Low-profile vessels (LPV)"
Type 4: "Hybrid go-fast boats."
I also recommend the H.I. Sutton web site without reservation or qualification.