Merc 5-blade vs. Merc 4-blade
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Merc 5-blade vs. Merc 4-blade
What pitch size do you move to for moving from a 4-blade to a 5-blade? Also, would a Formula Fastech 382 benifit at all from this change....or would it just look cool?
Thanks!
Thanks!
#2
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Re: Merc 5-blade vs. Merc 4-blade
Typically you will decrease one inch of pitch, but the Maximus is different. There are many variables such as its large diameter if stock. The normal pitch theories do not apply. Comparing a 32P Bravo I to a 32P Maximus you would to experience and RPM decrease of about 500-600 RPM. So you would need to drop pitch or reduce diameter when re-propping.
Julie
Julie
#3
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Re: Merc 5-blade vs. Merc 4-blade
Depending on the rpm you run with the 4bl and what you are looking for with the 5bl would determine the decrease in pitch. Plan on at least 2".
Decreasing the diameter of the Maximus isn't always necessary. If fact diameter is good if the boat can handle it. Meaning attitude of running surface, rpm, and most importantly what gear case you have. The prop will not hit every gear case.
As far as harder to Lab Finish, we Lab propellers different for certain applications. We don't find reducing diameter in the Labbing process to be a deterrent or more difficult.
Your rigs benefited would come in certain areas but possibly not in others. We would need to discuss your current numbers through the rpm range.
Decreasing the diameter of the Maximus isn't always necessary. If fact diameter is good if the boat can handle it. Meaning attitude of running surface, rpm, and most importantly what gear case you have. The prop will not hit every gear case.
As far as harder to Lab Finish, we Lab propellers different for certain applications. We don't find reducing diameter in the Labbing process to be a deterrent or more difficult.
Your rigs benefited would come in certain areas but possibly not in others. We would need to discuss your current numbers through the rpm range.
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Re: Merc 5-blade vs. Merc 4-blade
Has anyone compared a hydro 5 blade to the new 5 blade Maximus on the same boat? I am thinking of going to a hydro 5 blade on a 280 Velocity with a higher X than normal and looking at my options.
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Re: Merc 5-blade vs. Merc 4-blade
Interesting info.....but is there anything to gain going from 4 to 5? Is more better? That's basically my question. Geez Troutly, didn't you read my post!!!
#6
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Re: Merc 5-blade vs. Merc 4-blade
Yes, we have tried both the Hydromotive P5-X and the Maximus 5B on the same boat. The Maximus was much slower than the Hdyromotive. The Maximus did produce an increase in cruise as did the Hydro P5-X. We then labbed a Maximus and ran it again agianst the P5-X the speeds were much better for the Maximus. From our experiences the the Stock Hydro P5-X runs similar to that of a Lab Finished Maximus. So the choice is personal and financial for some. Now as far as gain when going from a 4B to a 5B the improvements are similar to that of when you went from a 3B to a 4B. You will have better hole shot, increased acceleration, increases in cruise speeds, improved perfromance and handling and less slip. Keeping in mind that slip translates into speed! Now as far as top end is concerned you may see increases, run the same or possibly lose 1-2 MPH on top. This is really a question as to how well the boat is currently dialed in. For example if you are currently running a 4B at 15% or so then it is possible that running a 5B at 9%-10% at the same RPM can possibly lead to net increases in top end or equal speeds with no speed loss, in which case pitch would be a variable. Hope this answers your question.
Julie
Julie
#7
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Re: Merc 5-blade vs. Merc 4-blade
Each and every identical application is different. I've seen the Labbed Maximus blow the doors off the stock P5-X. The P5-X needs a boat that flys it's bow on its own.
It's hard to make general consensus as to what will happen with all applications. Decreasing slip due to more blades doen't always happen because you have more drag from additional metal in the water. Also, more stern lift could affect the wetted surface area of the boat also increasing drag and slip.
Some of the generalizations made here I would agree with. More blades=better holeshot, handling, and mid range.
But,,,,only if the correct pitch is used and only up to certain rpms.
Don't get me wrong, 5 and 6 blade props are awesome on the right boat and set up. Race boats with high X's love them on rough water and short courses. They just aren't a cure all to the general boating public. Test, test, test. Seat time, seat time, seat time.
It's hard to make general consensus as to what will happen with all applications. Decreasing slip due to more blades doen't always happen because you have more drag from additional metal in the water. Also, more stern lift could affect the wetted surface area of the boat also increasing drag and slip.
Some of the generalizations made here I would agree with. More blades=better holeshot, handling, and mid range.
But,,,,only if the correct pitch is used and only up to certain rpms.
Don't get me wrong, 5 and 6 blade props are awesome on the right boat and set up. Race boats with high X's love them on rough water and short courses. They just aren't a cure all to the general boating public. Test, test, test. Seat time, seat time, seat time.
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
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#8
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Re: Merc 5-blade vs. Merc 4-blade
Originally Posted by bbladesprops
The P5-X needs a boat that flys it's bow on its own..
Matt
#9
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Re: Merc 5-blade vs. Merc 4-blade
No matter how much you rework a multi bladed propeller, more blades means more stern lift. Yes you can reduce diameter to settle the back down. But at some point the diameter reduction with destroy the geometry of the propeller and it won't do what it was intended to do.
Yes, as far as bow lifting 5bl's are concerned, the P5-X is round eared and does have some bow lift built in. No cut intended to the propeller. The fact remains, if you continue to lift the stern, there is less ability for the arm length to get the leverage to raise the bow. Therefore, high X, flat running, or C.G. adjusted boat can prosper from 5Bl props. Likewise, boats not needing bow lift will do well with this prop.
But, if you truly need more bow lift, this prop may not be the right choice.
Yes, as far as bow lifting 5bl's are concerned, the P5-X is round eared and does have some bow lift built in. No cut intended to the propeller. The fact remains, if you continue to lift the stern, there is less ability for the arm length to get the leverage to raise the bow. Therefore, high X, flat running, or C.G. adjusted boat can prosper from 5Bl props. Likewise, boats not needing bow lift will do well with this prop.
But, if you truly need more bow lift, this prop may not be the right choice.
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Brett Anderson / BBLADES Professional Propellers
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
#10
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Re: Merc 5-blade vs. Merc 4-blade
Carry the bow on what boats?
The rake on a Bravo 1 is only considered to be medium in degrees. It is also only a 4BL. You can't compare the two. Also, the Bravo 1 isn't concidered a huge bow lifting propeller anyway, although better than a Quad-4 or other 4blades.
The rake angle on the Maximus is actually higher than the Bravo 1. That would also make its rake higher than the P5-X giving it more bow carrying ability than the Hydromotive.
I guess we'll have to agree to diagree on this one.
The rake on a Bravo 1 is only considered to be medium in degrees. It is also only a 4BL. You can't compare the two. Also, the Bravo 1 isn't concidered a huge bow lifting propeller anyway, although better than a Quad-4 or other 4blades.
The rake angle on the Maximus is actually higher than the Bravo 1. That would also make its rake higher than the P5-X giving it more bow carrying ability than the Hydromotive.
I guess we'll have to agree to diagree on this one.
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Brett Anderson / BBLADES Professional Propellers
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Brett Anderson / BBLADES Professional Propellers
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