After at least 20 years, one prop re-build and a move from a "hot" galvanic spot in our marina, we just put on a new 14X14 Martec when we did our bottom job. Had it in hand before pulling the boat (Defender Marine). The old prop was a pitted 15 dia prop which would get good black smoke rolling at full teeth rattling throttle and make a nice wake for our power boat friends to admire. With the new prop, besides quiet shift changes now, have not seen any degradation of performance with the "smaller" standard prop. I would have replaced with 15 dia had I known that is what we were carrying - but it is all water under the boat now.
Just to close the story, old prop was traded to a cruiser buddy for a case of fine local IPA. The prop needs the $230+ rebuild job of welding and machining and he had a fixed bladed prop. I had a certain amount of pity for him as I had previously sold him an old headsail for $50 and a case of beer. He uses the headsail as a tarp now.
