Flex-O-Fold
Cram??! Not on an H37C, plenty of room for my 15" Flex-O-FOld. I was talking with Tom H. the other day. He has an 18" 3-blade on his H37C. But I really cannot comment on the H27. Except to say whatever diameter you were using is what the new prop should be. Usually only the pitch comes into question. There were no mods required on my boat. The one problem that I can foresee is length of the shaft AFTER the strut. The Flex-O-Fold has about a six-inch hub. But the end of the shaft will be INSIDE the hub. There are lock screws that keep the prop nut from loosening. So whatever the real hub length is figure that plus a little clearance from the strut. Then, of course, you need clearance between the folded blades and the rudder. I probably have one inch of shaft showing between the hub and strut and six inches or more between the folded blades and the rudder. I cannot say enough about forward performance. I have the small 2QM20 and displace over 18000#. I can motor in two-foot seas at 2600-2700 RPM at 6 knots. Backing is only slightly better than the original 2-blade. Still quite a lot of prop walk to port. An edit: I did not remember that you had an H27 so I checked the Directory, it says H30. And the specs for that boat call for a 13"x13". But I would trust the manufacturer, they were sure right on my prop. I guess you would need some kind of a return gaurantee just in case it did not fit.
