Area from Key West to Dry Tortugas (Florida)

Florida Reefs

On the straits side of the keys, and at an average distance of 5 miles, are the Florida Reefs, a dangerous line of shoals which extend along the entire length of the chain. These reefs extend from near Stuart, on the Atlantic coast, to the Dry Tortugas, west of Key West, in the Gulf of Mexico.

The most prolific reef development occurs seaward of the Florida Keys.
The reefs here are spectacular and rival those of many Caribbean areas. Approximately 6,000 coral reefs are found between Key Biscayne and Dry Tortugas.
The reefs are particularly hazardous because they do not break in smooth weather and few of them are exposed.
The water shoals abruptly between the reefs and along their outer edges. When approaching the reefs from seaward, their proximity usually is indicated by a change in color of the water from deep blue to light green or by the bank blink.
However, too much reliance should not be placed on such indications. Lights and daybeacons facilitate navigation along the reefs in clear weather, but soundings should be resorted to in thick weather. Depths of 50 fathoms indicate a distance of 2 to 3 miles from the reefs, and great caution should be used in approaching closer. Fogs are infrequent in this area. The water always becomes milky following windy weather. The usual color is bluish green on the reefs, while the rock patches are dark, shading through brown to yellow as they approach the surface. Sand patches are bright green. Grass patches at depths of 10 to 15 feet have the appearance of rocks. With the sun astern, the line marking deep water and the edges of reefs is surprisingly clear from a position aloft.