Prop rake angle
04-23-2017, 09:51 AM
#1
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Prop rake angle
A greater rake angle generally improves the ability of the propeller to operate in a ventilating situation. Ventilation occurs when blades break and re-enter the water’s surface — such as occurs with 1) a Bravo sterndrive installed with a high “X” dimension, 2) a surfacing drive (NXT1, NXT6 SSM or M8) or 3) an outboard installed or jacked high on a transom. In surfacing operation, higher rake can hold the water better as it’s being thrown into the air — deflecting it aft and creating more thrust.- Fred Kiekhaefer
Anyone ever try the higher rake angle props on a heavy flat bottom?
Seems like it would be the ticket for high x dimension cleavers and trying to lift the heavy bow of my boat.
Prop guy from Mercury thought the higher rake props have high slip numbers in the midrange but wasn`t sure..
04-23-2017, 07:39 PM
#3
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What did you try .. 18*??
04-23-2017, 09:28 PM
#5
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I dont have a high x, but the rake helped keep my bow up with my Outlaw. The Rev4 had more rake vs the B1 stock form. When I tried the Rev 4, it held the bow up well, better than the B1 until I had bblades lab the B1. I had planned on labbing anyway, so after talking to Brett (bblades), he explained the B1 labbed with better results, so I ended up doing that. Had I found a higher pitched Rev4 to try before labbing.. it may have changed the outcome of which prop i ended up with.
04-24-2017, 11:50 AM
#6
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I have found that the high rake angle on high X dimension tends to give a lot of tail lift and makes the boat walk a little. And if it has a heavy bow it wont carry the bow it just picks the back up and bow steers at high speeds.
04-24-2017, 12:29 PM
#7
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2x on Team Archer response.
I did a lot of testing with both the Dragon and GTMM with 5 and 6 blades and high rake. we had the same issue of the high rake lifting the ass end and making her unstable at high speeds over 80. They both likes a little deeper X with less rake. Much more predictable in high speed turns as well.
I did a lot of testing with both the Dragon and GTMM with 5 and 6 blades and high rake. we had the same issue of the high rake lifting the ass end and making her unstable at high speeds over 80. They both likes a little deeper X with less rake. Much more predictable in high speed turns as well.
04-24-2017, 03:10 PM
#10
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You can gut the cabin like I did and loose a bunch of weight----time boating, money, sanity ect. 
but you will probably be able to use the same props you have now.
but you will probably be able to use the same props you have now.
