folding prop

Hello folks, We have a new-to-us 2002 386. Under sail, we lose a full knot when the prop is locked. When left to spin, we are far faster. So, what I want to ask is: Does anyone else record this outcome? My owner's manual does not tell me if it should be locked or free, or am I missing...

We're considering switching from the 3 bladed fixed prop on our Beneteau 37 to a Flexofold 3 blade. I've reached out to our dealer and to Flexofold to find out what size they would recommend. The original fixed prop is 17" diameter x 12" pitch, 3 blades. Our dealer said they would outfit it...