If you are clear of Red buoy #8 off of the
Ohio Shoal you are clear of anything to worry about. That's about 10 miles offshore. You certainly won't run aground in closer, but there are shoals as shallow as 12 feet of so. If there is ANY kind of swell running, 12 feet can result in a surprise breaking wave.
How far you transit this area offshore depends on a couple things. Which way are you going? If southbound, hug the coast to find the least unfavorable
current. Alternatively, get WAY offshore outside the
current. If northbound, find the center of the
Gulf Stream and ride if for a free 3.5 or 4
knot boost.
Be careful of this region when there are launches from the spaceport. They are a lot more common than they used to be! There is a large
safety zone offshore, and you NEED to be clear of that. You need to
monitor CH16 as you transit this region, listen to the bulletins, and be prepared to get out of the way, or get very far offshore if a launch is scheduled. Your charts will have the
safety zone marked.
They will scrub a launch if there is a
boat in the safety zone, and you do NOT want to be the guy who caused a $50 million dollar rocket launch to be scrubbed.
P.S., Unless you are bottom trawling, you can just ignore the "unexploded ordinance" notifications offshore.