You're not going to find 91 anywhere...but these places have 93.
On the South River, there is Turkey Point Marina, Anchor Yacht Basin (within 100 yards of Turkey Point) and Londontowne marina. City dock used to have it, but I'm not sure about now. I know that Red Eye's doesn't have 93 anymore, but I think that the place directly across the Narrows does.
That's all that I've got!!
I'm thinking that you have a Cig Tiger (according to your name)?? Where do you boat out of?