That's not a drug boat - it's one of those new multi-engine testing modules . It is much more efficient to test eight engines at once.
To do the test effectively, a course from
Miami to
Mexico and back is laid out and the boat must proceed at top speed and only at night. To gain the best indication of how the engines will perform under load, as much 'ballast' as possible is loaded in
Mexico for the return trip. This ballast is then off loaded as quickly as possible in waters close to Miami onto the official test monitoring vessel standing by. This is usually a local nondescript boat that no one would notice - they don't want to draw attention to the testing so competitors won't spy on them or want tpo form a 'joint venture'.
So you see it's totally legit - really - you swabs have such vivid imaginations!