Piranha props are composite propellers designed with replaceable blades that fit into a universal hub assembly. When I installed one on the 90 hp Mercury outboard powering a 17-foot Boston Whaler, I noticed little difference in performance. The engine still wound up to maximum rpm, and the top speed, as reported by GPS, remained the same as with the stainless-steel prop normally run on this engine. During time-to-plane trials the stopwatch granted a half-second advantage to the stainless wheel. In all, this tells me that the Piranha can serve as a primary prop, not just a backup, if you so desire.
The key feature of Piranha props is the fact that the blades are replaceable. Using a simple mallet (or a block of wood), I found it easy to remove and replace the blades on my test prop. This means that boaters can fix their own prop after a hard grounding rather than send the wheel out for a reconditioning job. Additionally, the ability to change blades also allows you to change pitch. Select lower pitch blades for increased hole shot and higher pitch blades to deliver more top end. Replaceable hub inserts allow retrofitting to all engine makes. The tough Verton composite material is noncorroding.
Single-prop prices range between $90.75 and $165 for three blades, and $165 to $189 for four blades. Propulsion kits (the hub, two sets of blades, the prop wrench and a gear bag) range from $152.75 to $285.50. Props are above the price of aluminum props and about half the cost of those made from stainless steel. A floating prop wrench is also available for $22. 800-235-7767; piranhapropellers.com