More Performance Possible?

hwsiii

Commander
Joined
Jan 25, 2009
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2,639
Re: More Performance Possible?

Yes, I had a prop picked out but when I checked on it, it had too much rake and would not have raised the stern enough.


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carolynrose

Petty Officer 3rd Class
Joined
Oct 29, 2008
Messages
99
Re: More Performance Possible?

Tough one, right?

All the catalogs and web sites I visited before I bought the current prop had very few choices. I think I currently have all the current sizes from the Michigan recommendations.
 

slasmith1

Lieutenant Junior Grade
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Dec 2, 2008
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Re: More Performance Possible?

I had a 2560 years back (it is the exact same boat except it says trophy instead of bayliner) I test drove several before I bought mine. Every one that I drove that hadn't been upgraded to a duo prop set up felt like a total dog and exhibited the same symptoms you described.
 

hwsiii

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Jan 25, 2009
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Re: More Performance Possible?

Yes, the problem is finding the 13" pitch, everybody has the 15" pitches but I am waiting on a call now from Volvo.


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hwsiii

Commander
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Jan 25, 2009
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Re: More Performance Possible?

Sla, I agree that having a duoprop would help tremendously, that is why he needs stern lift and the 4 blade prop.


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carolynrose

Petty Officer 3rd Class
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Oct 29, 2008
Messages
99
Re: More Performance Possible?

Ah, if only I could afford a Volvo DP or Bravo III. But the cost of those units is probably more than the boat is worth.

Any luck yet hwsiii?
 

slasmith1

Lieutenant Junior Grade
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Dec 2, 2008
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Re: More Performance Possible?

Sla, I agree that having a duoprop would help tremendously, that is why he needs stern lift and the 4 blade prop.


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you are talking about a 25' 6" boat with a 10' beam that weighs approx 5600lbs dry a four blade prop will not make a noticeable difference. these boats also came stock with the bennett tabs, they were just under powered from the start to make an affordable mid sized boat.
 

hwsiii

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Jan 25, 2009
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2,639
Re: More Performance Possible?

THe only thing I can come up with is to buy a Volvo Penta 15 x15 QL 4 blade and if it lowres the RPM too much have it repitched to a 13" pitch, that is it.



Price: $117.98
Add QL Aluminum Propeller Prop: 41102331 Hub: 41102355 To Your Cart

Propeller Specifications:
SKU:prop #41102331Hub #41102355
Manufacturer: Volvo Penta
Brand: QL
Material: Aluminum
Diameter: 14 - 3/4?
Pitch: 15?
Blades: 4
Rotation: Standard (Clockwise)
Usually Ships Within: 1 Business Day


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carolynrose

Petty Officer 3rd Class
Joined
Oct 29, 2008
Messages
99
Re: More Performance Possible?

Do you think this prop will help bring the boat up on plane and hold it there easier or am I just stuck with the way it is as others suggest?

I also noticed that there was a Solas Rubex 9513-148-15 with a slightly larger diameter or am I barking up the wrong tree in assuming that the larger diameter will help lift the boat.

Is repitching a prop a common thing to get done?

I was thinking I could widen the trim tabs over the winter, as I noticed that on the Bennet site they say my tabs should be 30" wide and they are less than half of that.

Just fishing for ideas to get the most from my combo. Appreciate all your help!
 
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hwsiii

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Jan 25, 2009
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Re: More Performance Possible?

The whole reason we have been doing this is because we want to get the stern up on the boat so that you don't have to run it at almost wide open to keep it on plane.
The larger diameter will just lower the RPM more than we are going to lower them already with the smaller diameter, we don't need that.
No, repitching a prop is not really an ordinary thing to do, usually it is done when somebody buys the wrong prop and they need to get more RPM. Our problem is we can't find a 13" pitch stern lifitng prop for your outdrive.
Trim tabs do help hold the stern up on a boat, I had a set of 36" long tabs on my 38' Chris Craft and they helped, but they also created drag when I used them to help hold the stern up, but when I got the right props thattt really helped.
But if you just want to buy the Michigan Wheel 15 x 13" I certainly understand, because everybody else says we are just wasting time and money, and I certainly don't want to do that.


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carolynrose

Petty Officer 3rd Class
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Oct 29, 2008
Messages
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Re: More Performance Possible?

Don't be offended by my questions. I warned you back on post #13 that I can be obsessive when I get on a project. I really do appreciate all your help and time you have put into my problem.

It is in my mechanical nature that I want to understand completely as best I can.

I am going to try the prop you recommended. It may take a few weeks to get it done. But I will get back to you and pick your brain again.

One more dumb question. If I enlarge my trim tabs and turn them off once I get on plane does this also help the cause. Or is this just another excessive thought? Thanks again, Dave
 

hwsiii

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Jan 25, 2009
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2,639
Re: More Performance Possible?

Dave, I wasn't feeling offended. LOL I was just telling you that I would understand if you didn't want to go with my recommendation because everybody else is saying I am absolutely wrong.
It certainly doesn't hurt to have larger tabs if you don't deploy them down hard in the water, when they are just even with the hull that make the hull a little longer which helps hold it up, but when they get deployed very deep they act more like brakes and creates more drag on the boat.


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slasmith1

Lieutenant Junior Grade
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Dec 2, 2008
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Re: More Performance Possible?

One more dumb question. If I enlarge my trim tabs and turn them off once I get on plane does this also help the cause. Or is this just another excessive thought? Thanks again, Dave

Even with the duo prop set up that is what I had to do for the duration of the time I owned my boat of that make/model.
I know this isn't what you want to hear but this is one of the negative traits of that model boat and why you will find so many of them that have been re powered.
 

carolynrose

Petty Officer 3rd Class
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Oct 29, 2008
Messages
99
Re: More Performance Possible?

I have considered upgrading the engine to a 383 stroker, but from all the information I have garnered the OMC Cobra Outdrive is only capable of about 300 horsepower maximum.
To Upgrade the motor and the outdrive just wouldn't be worth it, I could probably find another boat for that kind of money.
At this point I really like the boat, it is probably one of the nicest examples you would find, but I also know the value of it.
I am trying to maximize what I have and enjoy it for what it is.
I am going to try the recommended prop and enlarge the trim tabs, both of which are very low cost.
 

hwsiii

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Jan 25, 2009
Messages
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Re: More Performance Possible?

I want you to understand all of the theory I am using to try and make your boat ride higher in the stern and thus plane easier. I am still waiting on the call from Volvo, I will call them today.
Finding the BEST prop for your boat would require trying many props to get the best performance we could out of it.
My intentions are not to find the BEST prop, just a prop that helps bring the stern up, that is our problem, with the power that you have available and the hull form that you have it makes lifting the stern a very important consideration in order to see any improvement in lower planing speeds and cruising.
This is a science to a certain degree, that is why i have all of the different formulas that I use to try and prop a boat correctly, not always the BEST prop, but a much better prop than what is on there now.
BUT, then it becomes an ART and NOT science, because of all of the different types of blade geometry available and hardly any manufacturers will tell you anything about the blade geometry of their props. That way they can get you to buy three or four of them instead of just the basic two you need. Normally you need two props, one for normal circumstances and another for heavy loads and to be used as a spare in emergencies.
I can't tell you how many arguments I have had with manufacturers not wanting to give me the blade geometry of their props, like it is a trade secret or something, and they justify it by saying it is. That is a lie because any good prop shop can tell you every detail involved with the blade geometry of a specific prop. The reason they don't want that information available to the public, they won't even give that information to dealers so they can sell more props. That is why people like Dhadley and Walleyehed are so good at picking the correct props for boats, because they have extensive backgrounds in actually using so many different props and over the years have gained tremendous knowledge of what prop works on what boat and motor combination, be it a stern drive or an outboard.
I hope this better explains what I try to do here, 99% of the people who come here are not looking for the absolute maximum potential from their boat, and aren't willing to spend the time and money required to do that as well. I feel my job here is to find a much better prop than what they have on their boat at this time, I do not have the background in prop testing like Dale and Kenny do and never will. Any time they make a recommendation for a prop for a boat, people ought to listen very hard, as Tailgunner once told me, before I knew about their qualifications.


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carolynrose

Petty Officer 3rd Class
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Oct 29, 2008
Messages
99
Re: More Performance Possible?

Understand, I was responding to slasmith. I think you and I are on the same page. I'm just looking to make my boat more user freindly. As I said before I'm not looking for a rocket ship, just trying to have it labor less in the way I use it.

In response to slasmith, I totally understand the limitations of the boat. But because of the age and value a repower is out of the question. Volvo makes a kit for Cobra conversion tto Volvo SX, before a conversion to DP it is about $6500.00 just to make it SX. The book on the boat is under $10,000. I like the boat but am also a realist. In todays market it is possible to get a lot of boat for the money.

A slight power upgrade I am capable of but the limitation in the outdrive is still the sticking point.

I appreciate your input but at this time I'm going to experiment with the prop recommendations and during the winter enlarge my trim tabs.
 

carolynrose

Petty Officer 3rd Class
Joined
Oct 29, 2008
Messages
99
Re: More Performance Possible?

hwsiii. I also understand the science and art of trying to make components jive with each other. Since I retired, I have been teaching Auto in a Vo-
Tech school and we have a race car that we run at the local dragstrip.

As you said, people think just throwing power at it makes it work better, but the truth of it is that making the components work together is much more important. Every vehicle responds to different combinations and there is no set formula. If there was anybody could do it. It requires investigation, science and a whole lot of "voodoo art".

Again, thanks for your time and effort!
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: More Performance Possible?

LOL I agree, it requires that certain je ne sais quoi prop, the american version. LOL
 
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