Caneel can be rolly, but if you're in a cat, no worries.

Maho / Francis bay has a huge mooring field. Good Snorkeling in Little Maho I hear.

Leinster Bay is also very nice.

Trunk Bay has day moorings and you can dingy in to a calm beach and even snorkel the underwater snorkel trail from the beach.

all of these are short on facilities and long on views and "remote feel" ambience.