No matter how much experience you have, no matter how sophisticated your computer modelling program is, there is only on way to know if any given propeller is correct for your boat: try it! Piranha fully accepts this and offers you their blade exchange program to ensure that you get the best prop available (featuring removable blades), in the best size possible for the way YOU actually use your boat. This approach fits especially well with the concept behind the Piranha Propeller: just change the blades, not the whole prop. Try the blades that are most likely to work best, if they don’t, pop them out and exchange them for a different size. Even if you find a metal propeller maker willing to exchange a prop, 2 lbs of Piranha Blades in a small box will save you more on shipping that a 10 lb. one-piece metal prop.
Exchange blades must be in re-sellable condition. Please keep this in mind when you get your new prop. Test your new prop in familiar waters where there is low risk of the prop contacting foreign objects. Hitting or scraping something with the prop probably won’t make it unuseable, but it also won’t leave it looking as it did when new and thus non-returnable. Finally, if you wish to paint or coat your prop with red laquer or anti-fouling paint, please do so AFTER deciding to keep the prop. Piranha will decline your exchange request if you return a red prop to them. Exchanges will be charged additional shipping costs