I changed my fixed three-blade for a Kiwi feathering, composite prop. In winds up to about 10 kts it added 1 kt to boat speed. It has less prop walk and reverses well. Three of us at the RCYC in Toronto have the Kiwi prop. It is far less expensive than Flexfold and other alteratives.
Nicholas Hirst
Mirthin N30U #513
RCYC Toronto