prop advise for baja 275
03-18-2013 | 06:29 PM
#11
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Joined: Jun 2004
Posts: 7,320
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From: frankenmuth michigan
Does your boat crawl to 5900 or get there real easy, where is your rev limiter set? Have you verified the tach calibration (compare it to a digital timing light), you have to just keep trying and you will find a little speed here and there, Smitty
03-19-2013 | 10:48 AM
#12
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Joined: Jun 2003
Posts: 3,878
Likes: 47
From: Princeton, Wisconsin
Am I missing something? It looks like jeromeke has a slip % of over 20%.
Shortys on these hulls are most often a mistake unless the boat is close to or can do triple digits. Or, if speed is all you care about and carrying loads isn't a often occurance.
Remember, every identical boat is different. The correct recipe 26 Bravo 1 should get you the best all around performance. We have been using them in various configurations for almost 20 years on these hulls. There are starting points that must be followed by subtle modifications.
I'm still concerned about your slip percentage. It is true that in certain instances, true V bottom boats can obtain their best top speed numbers with slip numbers in the upper teens. However, this can compromise planing and fuel ecomomy where you operate the boat most often. Determining your ultimate goals is also a big part of the equation.
Good luck and above all have fun.
Brett
Shortys on these hulls are most often a mistake unless the boat is close to or can do triple digits. Or, if speed is all you care about and carrying loads isn't a often occurance.
Remember, every identical boat is different. The correct recipe 26 Bravo 1 should get you the best all around performance. We have been using them in various configurations for almost 20 years on these hulls. There are starting points that must be followed by subtle modifications.
I'm still concerned about your slip percentage. It is true that in certain instances, true V bottom boats can obtain their best top speed numbers with slip numbers in the upper teens. However, this can compromise planing and fuel ecomomy where you operate the boat most often. Determining your ultimate goals is also a big part of the equation.
Good luck and above all have fun.
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]
03-24-2013 | 01:24 AM
#14
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I have a 27 pitch spinnille that would work great on your boat , lots of bow lift big round ears , there iis 28 pitch labbed for sale on the oso. The fasted i have every runs was with a 30 labbed bravo 1 83 mph at 5100 rprm i have some left in the power range put some new eddie marine thinders on it that may give mine aa little more rpm . I have have 4 blades know can send you pics of mine , buy mine i will buy the 28 . If it dosnt work well send the 27 back and i will send the 28 . just like to play with props did some bottom work also . I think i am going to put that spinnille on my rev limiter ' IM me we can talk...i really like the spinnille but i also have a 30 like it
your boat loves bow lift to make it go
scott
your boat loves bow lift to make it go
scott
Last edited by fastscarab22; 03-24-2013 at 01:31 AM.
03-24-2013 | 01:52 AM
#15
Charter Member # 55
Joined: Oct 2000
Posts: 20,271
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From: Omaha/LOTO
03-25-2013 | 06:45 PM
#16
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Joined: Feb 2011
Posts: 59
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From: LAKE LIVINGSTON TEXAS
I wasnt saying if you do this it WILL decrease slip. It was a question posed to would it if you did?
[QUOTE=articfriends;3887330]
[QUOTE=articfriends;3887330]
If you increase your pitch you are going to decrease your rpms...if you do this, will you be able to decrease slip to increase speed? Else, you are going to decrease top end...[/QUOTE
Increasing pitch alone isn't necessarily going to lower "slip" its only going to lower rpm and once you get motor away from the power band boat will most likely go SLOWER. Going to a prop with more surface area/blades or effiecient design will lower slip but again as slip lowers you will get away from the power band peak and again may slow boat down. It may be possible to lower slip with a ideal prop and then have to go down in pitch to keep motor near its power band. Lets say your boat "peaks" at 600hp at 6000 rpm's, lets say it takes 600 hp to move your hull thru the water at 75 mph, your current prop turns 6200 and boat is running 72, you go up slightly in pitch and at same time a prop expert does some work to your prop to make it more effiecient, now boat goes 75 mph at 6000 rpm's and your pretty happy.
Scenario 2 (which is more real world)same everything except instead of having a custom tuned prop built you go up from lets say a 24 to a 26 , if your boat could turn it at the same slip you would now go 78 mph, problem is the extra 100 hp you needed to go 78 isn't there so instead boat just lugs at same speed and goes 5700 rpm's or maybe goes a mph or 2 faster and is below hp peak.
The boat would also then be a pig accelerating because it would be working harder to get to its sweet spot. Propping boats can be alot of trial and error and certain hulls have a "normal" amount of slip that just goes with the hull.
My own boat, I chased after lower slip numbers before convinced that there was some speed I was leaving on the table somehow, tried a 5 blade , boat cruised at a incedible slipe rate under 10%, it also torque rolled and went SLOWER at wot, then it sheared off a prop shaft. There is gains to be had, they are just smaller than what most would think they are unless you have the totally wrong prop on your boat to start with, Smitty
Increasing pitch alone isn't necessarily going to lower "slip" its only going to lower rpm and once you get motor away from the power band boat will most likely go SLOWER. Going to a prop with more surface area/blades or effiecient design will lower slip but again as slip lowers you will get away from the power band peak and again may slow boat down. It may be possible to lower slip with a ideal prop and then have to go down in pitch to keep motor near its power band. Lets say your boat "peaks" at 600hp at 6000 rpm's, lets say it takes 600 hp to move your hull thru the water at 75 mph, your current prop turns 6200 and boat is running 72, you go up slightly in pitch and at same time a prop expert does some work to your prop to make it more effiecient, now boat goes 75 mph at 6000 rpm's and your pretty happy.
Scenario 2 (which is more real world)same everything except instead of having a custom tuned prop built you go up from lets say a 24 to a 26 , if your boat could turn it at the same slip you would now go 78 mph, problem is the extra 100 hp you needed to go 78 isn't there so instead boat just lugs at same speed and goes 5700 rpm's or maybe goes a mph or 2 faster and is below hp peak.
The boat would also then be a pig accelerating because it would be working harder to get to its sweet spot. Propping boats can be alot of trial and error and certain hulls have a "normal" amount of slip that just goes with the hull.
My own boat, I chased after lower slip numbers before convinced that there was some speed I was leaving on the table somehow, tried a 5 blade , boat cruised at a incedible slipe rate under 10%, it also torque rolled and went SLOWER at wot, then it sheared off a prop shaft. There is gains to be had, they are just smaller than what most would think they are unless you have the totally wrong prop on your boat to start with, Smitty
03-31-2013 | 03:37 AM
#17
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Joined: Apr 2006
Posts: 56
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From: zeeland netherlands
prop advise
We run a normal b1 26
74 mls
5600 rpm lots of shine walk
we tryed a mirage plus 25 75 mls but a smooter ride a am thinking abouthe a mirage plus 27 labbed, anyone a prop for sale?
74 mls
5600 rpm lots of shine walk
we tryed a mirage plus 25 75 mls but a smooter ride a am thinking abouthe a mirage plus 27 labbed, anyone a prop for sale?
