Actually, these some guys are pretty full of it. GFS is very close with his spinning tale.
The truth is that back in the late 50s and early 60s, the Castro revolution forced a lot of fine and successful Cubans off their homeland because they weren't going along with his political plans.
In order to to cope with expected waves of exiles and eventual refugees, the CIA created a physical and geo-thermal diversion of the Gulf Stream. How they did this remains classified but some of you guys with high level clearances probably are familiar with the program.
Several key cuts (Government Cut was the first of these) were cut around key keys to draw this hydro-thermal diversion toward the mainland and in turn the altered water flow created the southward eddying effect you now have in Florida Straits. This cold war maneuvering (done mostly in the dark) was intended to slow down the flotillas coming up from Cuba to make the integration of these exiles into Miami a little more manageable to local government in south Florida. The channeling work was carried out by the Army Corp of Engineers.
The current exchange was so effective that the CIA had to find a boat strong enough to cut through that southbound rip current so they could spirit certain favored Cubans out of Cuba on their own time table. Thus the SeaCraft 21 was born... The rest is history.
