I have a '97 Bassmaster 15 foot fiberglass boat with 100 hp evinrude. Is there anybody out there running a similar rig? If so could you tell me your prop size? Need a new prop and I'd like to know if I need replace or upgrade. mine has a 13 1/4 x 17

In see this asked all the time. I just copy and paste my answer for this question.  

here it is

That is a question I have seen asked many times on many different forums. I took the time to write the following to help people make this choice. It is long winded but should help people in selecting the correct prop.

This information is the same no matter what size your motor is or how long your boat is. You will need to do some research first before you can find out what the correct prop is.

First, you need to know. What is the maximum recommend RPMs for your motor? You can find this out my looking at the manual for you motor. If it is not there, look on the web or call the manufacture. The key to getting your boat to perform is getting the motor in that range a full throttle.

The second thing you need to know is what RPMs your motor is turning at full throttle. For that you need a tachometer. If your boat does not have one, I recommend one of these www.tinytach.com or www.sendec.com these are inductive tachometers that measure RPMs by counting when the spark plug fires. Please make sure you order the correct one for your motor. Both manufactures offer two and four cycle models. They also offer a model that can be used on both.

The third item you need to know is, the current pitch of the prop you have now. This info is the most important. With out it you will not know what size to get when you buy your next prop.  It should be stamped somewhere on the prop. If not there may be a part number you can lookup. If either of that info is not there a prop shop may be able to tell you.

An optional piece of equipment you might like is a GPS. This will tell you how fast you are going. The speedometers that use a water pick up are not accurate. The paddle wheel types are much more accurate. With GPS receivers available for under $100.00 you can also use it to save your favorite fishing holes.

You have gathered all the equipment from above. You are now wondering how do I make my boat go faster or improve my hole shot. Here you go.

Load your boat to the normal load you carry when you go fishing 90% of the time. Start your motor and head out at full throttle. Once your boat reaches its top speed for a minute look at you tachometer. Is it within the max RPM range from the data you gathered from above? If it is, that is all the faster your boat will go. If it is higher that the maximum RPM you should be able to get more speed by buying a larger pitch prop. You should do this anyway because you risk the chance of damaging your motor.  If the RPM is below the max RPM rating you can lower the pitch of your prop. This should allow for a better hole shot and increase boat speed by getting the motor into the RPM range where it makes the most horse power.

If you remember from above I said load your to what you would use it at 90% of the time. What about the other 10%? Those other times are when you bring or leave that extra person. One 175lb person and his fishing equipment with change how your boat performs. If you have great performance with just your self and a buddy with a prop with a pitch of Y you may find you add another person and their equipment you can not get on plane and you notice your motor RPMs is below the max RPMs allowed. This is where you need to have an extra prop with a pitch of X. The lower pitch will allow the motor RPMs to reach up to where the motor makes the most HP allowing your boat to plane better.

Now the opposite is true. If you go out in your boat by yourself you find out your boat get up on plane at break neck speeds, the RPMs are way high and top speed is low. This is when you need a prop of pitch Z with the lighter load you can get way with a higher pitch prop increasing top end speed.

After experimenting you will know what prop to put on before you leave your house. If I am going by myself I put on my 13 pitch prop. If the wife or a friend come along I put on the 11 pitch prop. With the right prop on before I leave, I always have the best performance.

On last thought to help you. Think of the pitch of a prop like a gear in a car. The lower the pitch the lower the gear. The lower the gear the more power but less speed. Since boats do not have multi-gear transmissions like a car we need to change gears by changing the pitch of the prop.

Hope this helps.

Thanks, but the prop on the motor would not be testable because of the big chunks in it. I was looking for someone with a similar setup so I could determine possible a high and low of what other people were running without buying multiple props.

I have a 99 Bass Stream 15' with a 2000 Johnson Ocean Pro 90hp and I'm turning a Raker 13 1/4 x 22" pitch prop.  The 90's top RPM is 5400 and the boat is doing 57 MPH per GPS.  It seems as if a prop similar to the one I have will work for you.   I can post a pic of the boat if you'd like so you can compare.  Hope this helps.  This boat is now for sale because I just bought a Nitro.  

Thanks ljmax that helps a lot.

Thanks, but the prop on the motor would not be testable because of the big chunks in it. I was looking for someone with a similar setup so I could determine possible a high and low of what other people were running without buying multiple props.

your best bet is to go to a marine dealership with a prop shop or a prop shop itself and get them to let you try different props on your boat before you go sinking money into a prop. You'll have no idea as to how it'll perform until you try different props and get some tach readings to help make the choice.  

Thanks ljmax that helps a lot.

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