I think there's a discussion on props in another thread, but I'll give you what I found on Tortuga's Lie. We bought the boat with a 16" X 12" folding Martec prop. It would power along in forward fine at around 6.2 knots at 2200 RPM's, Westerbeke 40. The reverse sucked on this prop but it was an old design. A year ago, I decided to switch out props. I went with a Varifold 16" X 11" (as per manufacturer recommendation). I now am about the same in forward and can reach a little under hull speed at 3000 RPM's, so I think it is about right for this brand. The reverse is NOTICEABLY improved
I was real tempted to go with Flex-o-fold but they never returned calls or e-mails after several attempts. Varifold was very, very responsive in my book. Rick Steadman is the US rep for them.