Thats because there is nothing that distance from shore that could even remotely be a hazard.
And how do you know this?
Because I'm not familiar with the area I did a search "Water depth 13 miles off shore from St. Augustine"
This is what I found.
From the NOAA Nautical charts.
" 332 U.S. Coast Pilot 4, Chapter 10 01 DEC 2019
ENC - US4FL80M
Chart - 11484
(60) From Ponce de Leon Inlet to False Cape the coast is
straight. The 5-fathom curve is about 0.5 mile offshore
for a distance of 24 miles.
Beyond this distance dangerous
shoals and wrecks and numerous fish havens will be
found up to 15 miles offshore.
(61) Ponce de Leon Inlet (see chart 11485) is 53
miles southward of St. Augustine Light and 41 miles
northwestward of Cape Canaveral Light. It is used by
both recreational and small commercial vessels bound for
New Smyrna Beach or Daytona Beach as well as others
entering for an anchorage."
While this area may not be the exact location being discussed it shows things are lurking up to 15 miles offshore in this general vicinity of Fl.