Eddy Currents


	Under Sea Adventurers Dive Club

Gulf Stream Eddies; Notice to Divers

Ray McAllister

Divers, and for that matter, boaters, need to know something about the currents off this part of Florida. There are special "currents" on the continental shelf of SE Florida, that is, within the one to three mile zone of relatively shallow water nearest the shoreline where we dive! We call them eddies!

They are developed as the Gulf Stream sheds rotating masses of water along it's western edge, in the Florida Straits. Since these eddies, when they are developed, flow in elongate ovals, the currents vary in speed and direction according to your position in them and they cause more problems for divers than the Gulf Stream itself.

These eddies, usually about 10 to 20 miles long and 1 to 3 miles wide, are spun off by the west edge of the current, and move north with the Gulf Stream, rotating counter-clockwise as they go. Since the eddies start at the edge of the Stream, they carry clear blue water west across the reef onto the shallow continental shelf, only one mile wide off much of SE Florida.

On the west side of the eddy, the water flows south, until at the south end of the eddy it flows back eastward to join the Gulf Stream again. At the south end, the eddy picks up dirty water coming out of the inlets on a high tide, and the diver suddenly has visibility go from 100 feet to perhaps 20 feet during a dive, and worse, the current may reverse direction as an eddy goes by. When anchor diving, one suddenly is swimming WITH the current instead of into it; bad news as you try to return to the anchor.