When I bought my Hatteras, I had an elderly blind cat. He did just fine and never went outside. He lived to be 21 years old, his last 9 years being on a boat. When I realized I could not live without a cat after he passed, I foster failed on the one I have now. He did just fine, too. And last week, a friend of my shot and killed himself, so I have a pocket panther (black cat) now, and he's doing just fine, too. Cats adapt well. My favorite cats are the ones nobody wants - the old, the blind, the 3-legged, the FIV+, etc. - the ones that have no other chance. I keep mine indoors, strictly, with the exception that they can go on the aft deck with one of us is out there.
Wifey B: You certainly get my admiration for what you do.