Clearwater prop

[JIm Smith]

I'm having trouble proping a new 19 ft. clearwater bay boat started from factory and now down to 15 pitch runs 33mph laoded ready to fish. prop has extra cup and motor is in the third hole on the tramson . 2011 115hp four stroke for power

[Steve Stinson]

What does the boat weigh with your partners, gear, gas etc? Also - How long is it taking you to get on plane with the 15 pitch and the motor trimmed all the way down?

The engine hieght needs to be set so that the flat part of the foot just above the prop is even with the bottom of your hull.

If you keep going down in pitch, you will over - rev your engine at wide open throttle. As you go down in pitch, you will loose top end speed, but gain rpms. You should also get a quicker hole shot.

- Steve

[Jumptrout51]

What are you looking for? More speed? More hole shot? Where is the gas tank located?

[DEMON]

I'm by no means an expert on this subject but here is how I have always set up my boats.

Steve is right about the engine height to the hull bottom. That is a good place to start. After you get that right, load the boat as you normally would and get it up on plane, (WOT) wide open throttle and trimmed to where you're not porpoising. Then have some one take the wheel and you carefully look over the stern and check to see that your anti-ventilation plate is on top of the water. It should not be buried where you can't see the top of it. It can have some spray going across it but you should be able to see it. If you can't see it, raise the motor and try again. After this you can try different props that get you at or near your motors max RPM.

Here's a link that explains it pretty well: http://www.veradoclub.com/smf/index.php?topic=137.0

I would stick to the prop that gets you at or near your max RPM. Then if you want a quicker plane time, consider trim tabs (if you don't have them). My 18' Tidewater gets up a lot quicker and in much shallower water with the tabs and I can still use the prop that gives me top speed.

[JIm Smith]

The boat came with trim tabs, the motor was flat on the tramson, with a 19 pitch from the factory. It would not plane at all, without the extreme use of the tabs. I went to the 2'nd hole on the motor next , then a 17 prop. 4700 rpms as a result. then to a solas prop 15 pitch, 6000 rpms 36 mph, next extra pitch was put in the 15 witch reduced my rpms by 200. I am now running the motor in the 3rd hole on the tramson with no problems and a good hole shot. I have heard that the yamaha prop and Solas props are not the best for this boat. the dry weight on this boat is 1600# hull only.

[DEMON]

Sound like you've got it dialed in. At 6000 RPMs running 36mph. I think that's about all you can expect from a 115hp on that hull. It's not a high performance package so I doubt you could tell much difference with another brand of prop.

[tin can]

Boat setup is mostly trial and error. Every boat is different. You can start with 2 supposedly identical boats and the setup will be different. But it boils down to 2 factors with any boat. Motor height and prop.

Jim, your boat is rated for 150 horsepower. You're running a 115. It's not going to be blazing fast. I would think you would want to set it up for maximum efficiency.

You want your motor as high as you can get it without blowing out or losing water pressure. I would suggest you install a 6" offset manual jack plate and a water pressure gauge. The ability to raise and lower the motor allows you the advantage of several different types of props. All props are not created equal. I would think you would want a prop with a fair amount of cup designed to be run on a bay boat. I finally settled on a Turbo Flats IV when I had my 19' bay boat. I think we discovered this prop is no longer made when we were setting up Showboat's boat. Capt. Ron's suggestion to call Powertech is a good one. They make several props for your application. They can probably come close to getting you the right style prop with the right pitch. They also allow you a reasonable amount of time to exchange props.

Mount the jack plate to the boat with the jack plate adjusted as low as it will go. Mount the motor to the jack plate so that with the motor trimmed to where the cavitation plate is parallel with the bottom of the boat, the cavitation plate is even with or just above the bottom of the boat. Mark the back pieces of the jack plate in 1/4" increments. I used a pencil, then a sharpie to do mine. Be sure to mark both sides of the jack plate so you move both sides the same when adjusting.

PB110001.JPG (545.73 KiB) Viewed 2095 times

Now the time consuming part begins. Load your tools up and go to the water. Run the boat at WOT with the motor trimmed as much as possible without the boat bouncing. Record the water pressure, speed and RPM. Put the boat on the trailer and raise the jack plate 1/4". Run the boat again. Repeat the process until you reach a motor height that the prop blows out or you start losing water pressure. Lower the motor 1/2" and you're done. After completing this process you should be turning maximum recommended RPM for your motor. If not, you need to change pitch accordingly.

By doing all this you will eliminate as much drag as possible. Less drag = more efficient.