pitch/size questions
03-21-2012, 10:39 AM
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pitch/size questions
I posted this yesterday and maybe I should have placed it here instead of the outdrive forum.
I'm still very green in the offshore powerboating world and am wondering which way to go.
My understanding from my surveyor is that my props are 15" w/ 26 pitch.
Even after lots of searching I'm still confused as which way to move forward on pitch and size
My goal would be hopefully an equal or higher mph cruising speed with a lower rpm. With the gas going up so quickly I'm not going to be banging out top speeds and would rather try to optimize fuel consumption. LMAO at myself for saying that here!!!
Here are my spec's, Baja 38 special, I'm guessing around 10,000 to 11,000 lbs with fuel and gear.
Pair of 525 SC's with intercoolers and the pulley change that offered more boost, powering through B1 outdrives on extension boxes fastened to the transom.
My current top speed last summer was 73 at 5100rpm
With our lake being so low last year I really didn't get any testing time to try to find the sweet spot rpm's before the secondaries kicked in.
As always you guys and girls are absolutely the best source of quality knowledge on these types of powerboats and y'alls advice has been spot on.
I look forward to any insight you may offer.
Thanks,
Kelly
My understanding from my surveyor is that my props are 15" w/ 26 pitch.
Even after lots of searching I'm still confused as which way to move forward on pitch and size
My goal would be hopefully an equal or higher mph cruising speed with a lower rpm. With the gas going up so quickly I'm not going to be banging out top speeds and would rather try to optimize fuel consumption. LMAO at myself for saying that here!!!
Here are my spec's, Baja 38 special, I'm guessing around 10,000 to 11,000 lbs with fuel and gear.
Pair of 525 SC's with intercoolers and the pulley change that offered more boost, powering through B1 outdrives on extension boxes fastened to the transom.
My current top speed last summer was 73 at 5100rpm
With our lake being so low last year I really didn't get any testing time to try to find the sweet spot rpm's before the secondaries kicked in.
As always you guys and girls are absolutely the best source of quality knowledge on these types of powerboats and y'alls advice has been spot on.
I look forward to any insight you may offer.
Thanks,
Kelly
03-21-2012, 08:21 PM
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Are the 26's labbed? If not go up to 28 labbed. That will bring down the rpm and increase the mid range speed. Call Greg at cutting edge and he will explain it to you. They can add the cup into the prop that bajas love with losing too many rpm's.
03-22-2012, 02:12 AM
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The 525SC's run best when spun 5100-5300rpms.
Just because the rpms are lower, does not mean they are using less fuel. You may still have to push the sticks just as far forward. All it does is force the engine to work harder at the lower rpm. Its like going up a hill in a truck. You have to push the pedal farther down to go the same speed and maintain your rpms. Bigger props will just place more load on the engines.
Just because the rpms are lower, does not mean they are using less fuel. You may still have to push the sticks just as far forward. All it does is force the engine to work harder at the lower rpm. Its like going up a hill in a truck. You have to push the pedal farther down to go the same speed and maintain your rpms. Bigger props will just place more load on the engines.
03-22-2012, 06:47 AM
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The 525SC's run best when spun 5100-5300rpms.
Just because the rpms are lower, does not mean they are using less fuel. You may still have to push the sticks just as far forward. All it does is force the engine to work harder at the lower rpm. Its like going up a hill in a truck. You have to push the pedal farther down to go the same speed and maintain your rpms. Bigger props will just place more load on the engines.
Just because the rpms are lower, does not mean they are using less fuel. You may still have to push the sticks just as far forward. All it does is force the engine to work harder at the lower rpm. Its like going up a hill in a truck. You have to push the pedal farther down to go the same speed and maintain your rpms. Bigger props will just place more load on the engines.
If the 26" is not labbed and spins 5100 at it's best, the 26 is the one to lab for 5300-5350 max rpms imo. Give Brett a shout about that, or perhaps Greg Hittner. Looks like he does very nice work as well. It's nice to have choices, I'm sure both will take good care of you and your props
Good luck with it and have a great season
Last edited by A.O. Razor; 03-22-2012 at 06:53 AM.
03-22-2012, 11:50 AM
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Hello Kelly,
I took into concideration the 73mph number is the best number you saw. Therefore, I feel your slip % is in the 12-13 range. This is typical numbers for your hull. It would be interesting to see what the 26's you have now actually are. Are they bone stock propellers or have they been modified or repaired somewhere.
If they are stock, Labbing 28 Bravo 1's to the correct recipe will aid in your fuel consumption. Griff is right that the fuel burn can be higher with the 28's if your hard on the throttles. However, once you reach cruising speeds, the 28 should sve fuel by allowing you to run the same cruising speeds at lower R's.
If you would like to call us, I can give you more details. We have been doing custom Baja propellers for 20 years both at BBLADES and Mercury Racing.
Brett
I took into concideration the 73mph number is the best number you saw. Therefore, I feel your slip % is in the 12-13 range. This is typical numbers for your hull. It would be interesting to see what the 26's you have now actually are. Are they bone stock propellers or have they been modified or repaired somewhere.
If they are stock, Labbing 28 Bravo 1's to the correct recipe will aid in your fuel consumption. Griff is right that the fuel burn can be higher with the 28's if your hard on the throttles. However, once you reach cruising speeds, the 28 should sve fuel by allowing you to run the same cruising speeds at lower R's.
If you would like to call us, I can give you more details. We have been doing custom Baja propellers for 20 years both at BBLADES and Mercury Racing.
Brett
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
03-22-2012, 04:29 PM
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Thank you guys for your responses.
Brett, my boat was the Baja Marine factory poker run boat of 1996.
It's still completely stock as delivered to my seller prior to my purchase last year.
I'm certain that the riggers of the boat gave consideration to many aspects of performance as equally as they did to the amenities in the salon when outfitting the boat.
My current props are probably the originals that came with the boat at delivery from Channel Marine. They are beat up bad on the edges and have a few knicks knocked out and look like $hit. Industry insiders said that my boat ran noticeably faster before when it was being campaigned. I have all the receipts from the seller and other than outdrive servicing there has never been an invoice for prop replacement.
My seller was in his late 50's when he bought it, all he did was have it delivered to his lake house at Lake Winnipesaukee, NH
Memorial day weekend and picked up after Labor day weekend, regular winter and dewinterization, standard maintenance, and then stored indoors for the next 9 months till summer.
He never did any modifications to the boat, and looking at my props I'd say he ground rocks with the props much more than once with authority. I don't even know if they're rebuildable.
The sad truth is that although I want the missing speed back, now I'm making an attempt to be more practical.
I'm curious what exactly does labbing and cupping do, and if I move up to a pair of 28's wouldn't that in turn raise my top end speed along with the cruising speed?
I'll be giving you a call.
Thanks to all of y'all, this site ROCKS with great knowledge.
See ya,
Kelly
Brett, my boat was the Baja Marine factory poker run boat of 1996.
It's still completely stock as delivered to my seller prior to my purchase last year.
I'm certain that the riggers of the boat gave consideration to many aspects of performance as equally as they did to the amenities in the salon when outfitting the boat.
My current props are probably the originals that came with the boat at delivery from Channel Marine. They are beat up bad on the edges and have a few knicks knocked out and look like $hit. Industry insiders said that my boat ran noticeably faster before when it was being campaigned. I have all the receipts from the seller and other than outdrive servicing there has never been an invoice for prop replacement.
My seller was in his late 50's when he bought it, all he did was have it delivered to his lake house at Lake Winnipesaukee, NH
Memorial day weekend and picked up after Labor day weekend, regular winter and dewinterization, standard maintenance, and then stored indoors for the next 9 months till summer.
He never did any modifications to the boat, and looking at my props I'd say he ground rocks with the props much more than once with authority. I don't even know if they're rebuildable.
The sad truth is that although I want the missing speed back, now I'm making an attempt to be more practical.
I'm curious what exactly does labbing and cupping do, and if I move up to a pair of 28's wouldn't that in turn raise my top end speed along with the cruising speed?
I'll be giving you a call.
Thanks to all of y'all, this site ROCKS with great knowledge.
See ya,
Kelly
03-22-2012, 07:55 PM
#7
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huskyrider,
Yes the whole reason for Lab Finishing is to improve a certain point of performance or to improve overall performance. Lab Finishing was invented and developed by my mentor, Dennis Cavanaugh at Mercury Racing. We have learned and progressed this process from blueprinting to "blueprinting on steriods" over the last decade. I can explain the ability for Labbing to improve certain aspects in depth at your convenience.
We'll look at the current numbers and they will speak volumes as to the potential Labbing can offer.
Thank you,
Brett
Yes the whole reason for Lab Finishing is to improve a certain point of performance or to improve overall performance. Lab Finishing was invented and developed by my mentor, Dennis Cavanaugh at Mercury Racing. We have learned and progressed this process from blueprinting to "blueprinting on steriods" over the last decade. I can explain the ability for Labbing to improve certain aspects in depth at your convenience.
We'll look at the current numbers and they will speak volumes as to the potential Labbing can offer.
Thank you,
Brett
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
03-22-2012, 08:22 PM
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Thank you guys for your responses.
Brett, my boat was the Baja Marine factory poker run boat of 1996.
It's still completely stock as delivered to my seller prior to my purchase last year.
I'm certain that the riggers of the boat gave consideration to many aspects of performance as equally as they did to the amenities in the salon when outfitting the boat.
My current props are probably the originals that came with the boat at delivery from Channel Marine. They are beat up bad on the edges and have a few knicks knocked out and look like $hit. Industry insiders said that my boat ran noticeably faster before when it was being campaigned. I have all the receipts from the seller and other than outdrive servicing there has never been an invoice for prop replacement.
My seller was in his late 50's when he bought it, all he did was have it delivered to his lake house at Lake Winnipesaukee, NH
Memorial day weekend and picked up after Labor day weekend, regular winter and dewinterization, standard maintenance, and then stored indoors for the next 9 months till summer.
He never did any modifications to the boat, and looking at my props I'd say he ground rocks with the props much more than once with authority. I don't even know if they're rebuildable.
The sad truth is that although I want the missing speed back, now I'm making an attempt to be more practical.
I'm curious what exactly does labbing and cupping do, and if I move up to a pair of 28's wouldn't that in turn raise my top end speed along with the cruising speed?
I'll be giving you a call.
Thanks to all of y'all, this site ROCKS with great knowledge.
See ya,
Kelly
Brett, my boat was the Baja Marine factory poker run boat of 1996.
It's still completely stock as delivered to my seller prior to my purchase last year.
I'm certain that the riggers of the boat gave consideration to many aspects of performance as equally as they did to the amenities in the salon when outfitting the boat.
My current props are probably the originals that came with the boat at delivery from Channel Marine. They are beat up bad on the edges and have a few knicks knocked out and look like $hit. Industry insiders said that my boat ran noticeably faster before when it was being campaigned. I have all the receipts from the seller and other than outdrive servicing there has never been an invoice for prop replacement.
My seller was in his late 50's when he bought it, all he did was have it delivered to his lake house at Lake Winnipesaukee, NH
Memorial day weekend and picked up after Labor day weekend, regular winter and dewinterization, standard maintenance, and then stored indoors for the next 9 months till summer.
He never did any modifications to the boat, and looking at my props I'd say he ground rocks with the props much more than once with authority. I don't even know if they're rebuildable.
The sad truth is that although I want the missing speed back, now I'm making an attempt to be more practical.
I'm curious what exactly does labbing and cupping do, and if I move up to a pair of 28's wouldn't that in turn raise my top end speed along with the cruising speed?
I'll be giving you a call.
Thanks to all of y'all, this site ROCKS with great knowledge.
See ya,
Kelly
