I wish I had a dollar for every time I have been asked this question. Being a fishing guide here in Central Wisconsin I meet an awful lot of people who really do not know that they can improve the performance of their boat by just changing the prop. I have heard many stories of folks spending a lot of money on Dole-Fins and other similar add on equipment to improve performance only to be even more disappointed.

So, what do you need to know to get the best performance out of your rig? I hope I can help you accomplish this task. I have had to replace many props, over my many years of fishing. I think all of you will be able to find the best prop for your boat by following the information I am about to give you. Some simple and yet important things to remember are, a one-inch reduction in propeller pitch will result in an increase of 150 to 200 RPM at full throttle. If at full throttle, the engine RPM is too high, you will need to try a prop with either a higher pitch or larger diameter. However, if the engine RPM is too low at full throttle, try a prop with a lower pitch or smaller diameter. Due to the differences in hull designs, engines, and weight (and how you load your boat) and from one boat to another, finding the correct prop for each boat will vary. Finding the best prop can only be accomplished by determining what is most important to you, speed, handling, trolling, etc.

There are many types and brands of props. Aluminum, Stainless Steel, SST = Stainless Steel Tough, SST II, Composite Props. There are some minor and major differences between the different models. The SST propeller is 5 times stronger than an ordinary aluminum prop. The SST is a fast planing prop with thru-hub exhaust and cupped blades. With its outstanding high performance feature, the SST is unmatched as the best value in a stainless steel prop. They are more expensive than aluminum, but highly recommended for the serious boater. If you pull water skiers, you will want a prop that has very limited flex to it. Heat Treated Stainless Steel that provides protection from minor dents and dings, There is also a four blade design, Left hand and right hand V6 sizes; Superior acceleration; Stays hooked up in all water conditions; Superior top end speed; Stays solidly on plane when running at minimum RPM.

There is a new kid on the block. The composite prop. COMPROP's are full-time, primary props. Many boat companies such as Regal, Wellcraft and Four Winns have used COMPROPs as standard equipment. Basically, if the boater is satisfied with aluminum performance, they will be happy with a COMPROP. If the boater is more demanding and wants the extra performance of a stainless steel prop, and does not mind the lower unit risk and price, a COMPROP would be a good choice for a backup. All types of family and fishing boats from 20 to 225 prop shaft horsepower can use a comprop. Being a Professional Fishing Guide, I cannot afford to have my boat tied up in the shop so I run these props as my primary prop. Fishing the waters here in Central Wisconsin that is stump ridden, this is the best prop for me to run, and they run on my 115Evinrude just great. So how do they perform compared to the others?

The new four blade series COMPROP’s have shown in tests by boat builders and major boating magazines to be at least as fast as top-notch aluminum props. In most tests, they were faster.

Boaters will find the new four blade COMPROPs also accelerate quicker, corner much better, and are very smooth at all speeds. I know you have heard that composites are nothing more than a plastic prop and are not worth the money, but you are very wrong to think that. Here is why. A high-tech composite material similar in strength to some aluminum alloys is used in making these props. The actual composition of COMPROP is a trade secret. How tough is it? Tougher than aluminum in most cases. If a boater is routinely digging up sand, mud, gravel, etc., while at low speeds or trolling in shallow waters, the leading edge will become scratched, but will not fold or blunt like aluminum props.

Aluminum props cannot withstand this type of environment. It is much too severe. They must be repaired regularly. On the other hand, while traveling at a high speed, if a boater strikes a Dead Head (like the picture to the left which I did at 30mph) or other underwater objects and has a severe prop strike, the COMPROP blades are designed to break away to reduce stress to the lower unit. In this instance, a COMPROP costs less than expensive repairs to the drive train. Had this prop not broken, the cost to the lower unit for repair would have run about $2500.00! Are 4 blades better than 3? Yes - for most applications. Increasing the number of blades improves acceleration. It also improves cornering and fuel efficiency while reducing vibration. If top speed is the highest priority, the fewest number of blades is desirable. Fewer blades mean less drag at top speed.

COMPROP four blade designs run just as fast as three bladed aluminum props. Keep in mind adding blades increases manufacturing costs in metal props. Most aluminum props have three blades because it offers a good compromise between performance and cost. Aluminum prop repair costs vary significantly. Generally, there is a choice between one new aluminum prop plus two repairs, or three brand new COMPROP’s. Keep in mind after several repairs to an aluminum prop; it becomes brittle and hard to repair. Each repair may also detract from original performance.

All prop blades flex during use. Aluminum is good for general all-purpose recreational use engines. It is cheaper and less durable than stainless steel. Most pleasure boats are factory equipped with aluminum props. A good quality aluminum prop will provide satisfactory performance for most family and fishing boats. For ultimate top speed or better acceleration, a stainless steel prop will probably be required. Stainless steel is much stronger than aluminum, and can endure far more abuse. If you can afford the higher price of stainless steel with the desire for top speed and acceleration, I would recommend stainless steel as the best choice overall. Stainless steel flexes the least; that is why stainless props generally have the best top speed. COMPROP’s flex about the same amount as an aluminum prop; that is why performance is similar.

It is a challenge to lead the change from traditional metal props to composite props. This is similar to fiberglass replacing wood in new boats during the 1950s. Fiberglass was a new material that lowered cost, maintained or improved performance and provided benefits the traditional material could not match. There was initial reluctance, then acceptance. It is true, history repeats itself.

The correct prop size (diameter and pitch), and material (stainless steel, aluminum, or composite.) will allow your boat’s engine to operate at the engine manufacturer’s maximum recommended engine RPM at full-throttle. For you folks that do not know, diameter is the distance measured across the prop hub line from the outer edge of the circle that is made by the prop’s blades during rotation. Pitch is the distance that a boat will travel for each revolution without any slippage. The actual distance the boat moves forward for each prop revolution is somewhat less, depending on the amount of prop slip. The diameter is listed first and the pitch is second. Therefore, a 14” x 21” propeller would have a 14-inch diameter and a 21-inch blade pitch. A higher pitch prop will increase your top-end speed, but reduce your acceleration (reduce your “hole-shot” power).

Decreasing the pitch will increase your hole-shot but sacrifice some of your top-end speed. If the hole-shot speed is important to you, (water skiing) then you would want to go with a lower pitch prop and sacrifice some of your top-end speed but increase your hole-shot speed to get the skiers up faster. If your prop is either too large in diameter or too high in pitch (or both), your engine will not be able to reach the maximum recommended RPM at full throttle, (assuming your engine is in otherwise excellent running condition). This condition will cause strain on the engine and cause poor performance. If, on the other hand, the prop is too small, in either diameter or pitch, the engine can be damaged by excessive strain. To find out what size prop is on your boat right now, look at the inside of the hub of the prop for either a serial number or the prop size stamped into the hub. Find the manufacturer’s recommended RPM range in the owner’s manual or ask your dealer. Using the existing prop or a new, make test runs to determine the maximum RPM and boat speed. This is known as “wide open throttle” (WOT). Vary the trim angle for optimum performance. If possible, test different types of props. Test the prop in a variety of water conditions; at a variety of speeds, under the conditions you will primarily use your boat (calm water fishing, rough waters, water skiing,). Running your engine at the wrong rpms can cause severe strain and lead to engine damage. An engine that revs past the manufacturers recommended RPM would have higher than normal wear and tear. Important: 4 blade designs allow your boat to stay on plane at a lower rpm - Producing a slower cruising speed without loss of plane of the boat in rough seas and conditions. Renegade props (4 blade) are of an excellent design allowing better top end, speed, with minimal drag.

No single prop will be able to give you top speed and handling under all conditions. The prop that provides the best hole shot will probably not provide the best top speed for your boat. A prop that will give you absolute top speed will probably provide uncomfortable midrange handling or ride. If you use your boat often under a variety of conditions, you will probably decide that you need more than one prop. One for cruising, one for speed and one for pulling skiers... of course, if your budget only allows one good quality prop, you will need to select the prop that provides the best compromise between the characteristics you are looking for. I hope this has helped you to better understand how choosing the right prop will benefit you.

If you have any questions on anything in this article, you can e-mail me at either [email protected] or [email protected]. I’d like also to thank my friends at Crestliner Boats, Bombardier Motor Corp. Magic products, Lake-link.com, Fish-Wisconsin.com, Fishtheriver.com, Lowrance locators, St.Croix Rods, Heckels marine, Amherst Marine, Comprop Props, ISG Jigs, Reeds Sporting Goods, Big Fish Tackle Co., Ipsglass.com, Thermoilbatteries.com, Pepsi of Americas, Beckman nets, Trojan Batteries, Black-Widow Fishing Line, TICA Reels, Minn-Kota Trolling motors, Austackle Lures, Exciter Baits, Jere’s Bait and Tackle, Tennesse Trailers, and others who have helped me along the way.

This article may not be reproduced, or used in any way without my written permission.

Bob is a Licensed Wisconsin Fishing Guide, and owner of Gone Fishing Guide Service. Specializing in Walleyes, on the Wisconsin River System. He is also an outdoors field reporter for many fishing web sites, Author, Historian on the Wis. River and the Petenwell Flowage in Central Wisconsin, and on many Pro-Staff programs for various tackle manufactures, Crestliner Boats, and Evinrude Outboards. He has written many articles on Walleye Fishing, and informational articles on the waters in Central Wisconsin.

PLEASE CPR ALL FEMALES…THE FUTURE OF FISHING IS IN OUR HANDS.