Great sailing around them. The only problem is they are well protected in most places from the prevailing SE winds, but can be rough when the wind
comes out of the W or NW.
Ship Island, although usually crowded, is one of the best places to anchor
, especially, near the old fort.
Horn Island is more desolate and a good place to anchor
is off the place marked as the "Horseshoe"
Cat Island is more complicated. There are some good anchorages
on the south side, but you almost need local knowledge to use them and there is a lot of shoal water
around Cat even though it has some really good anchorages
All of the bottoms are sand, or sand with a little mud mixed in and holding is always pretty good. Gnats can be a problem and can make anchoring farther out than really optimal for wind
and wave protection, necessary to save your sanity.
If your chart is pre-Katrina, be extra careful. There is a lot of shoals that were deep water
before Katrina. I ran aground one day in a place that used to be deep and I've been sailing there almost my whole life.
You can always put into marinas
in Pascagoula, Biloxi, Ocean Springs, Gulfport, Long Beach and Pass Christian in an emergency
or if you are nervous about getting caught out in bad weather
You almost never get a really strong north wind, so you don't end up on a dangerous lee that often when you anchor north of the barrier islands, and there really isn't anywhere to drag to, if you get hit with a strong E or W wind as long as you don't anchor in a cluster of boats, so it's not a particualr perilous place to stay. Uncomfortable at times, but that's about it.
Except for hurricanes of course. In that case, run like a scared rabbit.