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Revved Up, Eat em Up. New Way to Get Up and Go.

We put Piranha's props to the test, and found they stack up against the rest

By Bill Fedorko

One of the best things about being a boating writer is getting to test a variety of newboats, engines and equipment. But rarely are we invited to a test where we are encouraged to destroy something. So when Piranha Propellers of San Luis Obispo, California, offered to let us hit a submerged object in order to tests its composite propellers, how could we say no?

Piranha Propellers manufactures props from Verton, a composite material comprised primarily of long-fiber fiberglass and nylon. This makes the Piranha props virtually corrosion free, and it does not promote electrolysis, unlike props made of aluminum or stainless steel.

They are also modular, so you can easily replace any of the blades should they become damaged. Hence, the idea for the Piranha's test.

Those of us who have been in the boating industry for as many years as I have can remember the days when aluminum and a stainless steel propellers were the standard. Nowadays, however, there are a huge variety of props available - so the boaters must consider a number of factors when choosing the right prop for their needs.

While composite props aren't new, they have come a long way toward proving they are a cost effective alternative to aluminum and stainless steel props.

When composite props were introduced several years ago, they were primarily marketed as an inexpensive alternative for use as spare props. However, after having the opportunity to test some of today's composite props, I am convinced that many have shown they can hold their own agaisnt most aluminum and stainless steel props and that they are cost effective.

HIT IT

The first part of the test, or should I say destroy mission, for the Piranha modular composite props was staged to guarantee a prop strike. A 4x6 inch board was placed just under the water and anchored at both ends. Our test boat was a Sea Ray 170 Bow Rider powered by a 3.0L MerCruiser with the skeg cut off and a 14 inch Piranha prop.

We took off across the lake and set up our approach at a speed we felt comfortable with and aimed for the board. What a combination of apprenhension and thrill it is to intentionally hit an underwater obstruction (especially when you know you won't have to pay for the damage).

Each of us had a turn, and as you might imagine, we all hit the log. In some cases a blade broke off and in others two blades were struck. But because the Piranha props are modular, the damaged blade can be replaced within minutes, enabling you to get back under way with minimal delay. Plus, you don't have to carry a replacement prop on board, just extra blades.

Because of Piranha's high tensile strength, the prop blades are designed to absorb the impact generated by a strong prop strike. This proptects the lower unit from costly internal damage.

Another good reason to use Piranha props is that they perform as well as many of the aluminum and stainless steel props made by the major manufacturers.

RANK AND FILE

With a Stalker radar gun attached to a laptop computer I recorded the results of our speed test and witnessed first hand that Piranha has a competitive edge.

We hooked up our test boat with a variety of props, including those from Mercury, Solas, Michigan, OMC, Mach, Comprop, Propco, Hill, and of course, Piranha and put them through several hours of testing on Lake Nacimiento.

The results were quite interesting. According to my computer program, the Mercury 14x19 inch stainless steep prop, did the best, reaching almost 38 MPH in 20 seconds. But the 14x18 inch Piranha's performance was equally respectable, reaching 37 MPH in the same amount of time.

A Mercury 14x19 inch aluminum prop reached just under 37 MPH, the rapture 14.25x19 inch stainless steel prop did 36 MPH and the 14.25x21 inch Michigan Wheel Co's aluminum prop peaked at 35 MPH. Other test boats with different engines achieved similar results with various props. While stainless steel did the best in most cases, composite and aluminum weren't far behind.

BOTTOM LINE

So what does this all mean to boaters? Basically that the composite props can stand up right alongside some of the products offered by the mainstream stainless steel and aluminum prop manufacturers. Don't get me wrong, a well made composite prop is no match for a stainless one, but if you take into consideration the weight and expense, a composite prop is a viable option.

Piranha has also introduced a new perfomrace four blade composite prop which goes heads up with the best of the stainless steel props may be engineered to give, but not that easily. There were plenty of times during our demonstration part of the test, where after hitting the 4 x 6, only a small piece of the composite blade broke off - which suprised even the most cycnical writer of the bunch, me.

To order the correct Piranha Propeller for your boat you only need to provide the company with a couple of specifications. You'll need to tell them the year, make and model of your boat and its engine. They will also need to know the engine manufacturer's suggested wide open throttle (WOT) rpm and speed and how much horsepower it has. Then, they will want to know how you use your boat.

Based on the information you provide, Piranha will send you a prop to suit your needs. But, if you're not satisfied with the props' performance, you can exchange them for another pitch.

Piranha props are available in sizes to fit many popular stern drives, inboards and outboards (Correction 2006. Piranha does not actually make props for inboards). It has taken a while for the industry to get the word out on the strength and versatility of composite props but now they are here to stay.

A few decades ago, plastic was heralded as the building material of the future. Based on the promising performance of composite props, we are reminded why.