Drive Height for single with SSM#4
 

Hi Fellas,
Boat is a 27' Magnum but not a lot of them are singles. Figured I'd have better luck over here because there are more 28' Panteras with singles and big power.

I just picked up this 27 with a big shaft speedmaster 4. It has a mild 454 producing just over 500 Hp on the dyno. Trying to get it dialed in. Came with an 18" 26P 4 blade. Planed pretty good and ran well (upper 50's), just didn't have enough HP to swing it past 4300 rpms. Found a 15" 26P 4 blade on ebay. Figured it should spin it easier. Almost couldn't get on plane because it slipped so bad. Finally got it going and spun it up around 4900 rpms which is better but only 58 Mph. A bit more trim and it'll touch 5200 but it's just slipping and losing speed. My propshaft height is pretty high with the #4, about an inch above the bottom of the V. Obviously no pad, notch or step. Trying to plan my next steps. I think I need the big diameter to give enough bite, but a little less pitch. (Its hard to find smaller pitch 26 spline props) Would a 5 blade be worth the money for more bite? Should I try a 2" spacer or an extension box? I'm planning on adding another 150-200HP into the mix in the near future so this current prop may end up being about right. But my slip still seems really high, even at neutral trim. It does throw a hell of a roost with some trim but I know that its just cool looking and not productive.

What's everyone's thoughts on this propshaft height?

Thanks Guys
-Chris
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30 Checkmate with #6 and final set up was pretty low. I mention this because it's intended to be a surfacing drive same as your #4, however the rules change in a single application V-bottom.

Also it ran best with a special 3-blade the late Dennis Cavanaugh did his magic on. Brett Anderson @ BBlades is up to speed on this prop also. He has worked on it and also worked with Dennis.

Running 105 in this picture, best was 117

Also the reason for the 12" Extension Box on this set up was to have room for the Transmission.

Drive Height:

12" Stellings Extension Box
#6 Drive DrySump / LH Rotation
Bullet is about 4.5” below the bottom of the boat
1:24 Ratio
16.5” Dia.
28” Pitch

Good to know, Thanks Cougarman. That's a wild setup. I've heard about it, its cool to see the pictures.
Thanks

We used to run the A boat a about 1.5 inches below the bottom if that helps. That was a Number 6 drive

Ya thank you that is helpful, I'm about an inch above so a 2" spacer might get me pretty close. I appreciate the feedback

[QUOTE=cougarman;4935451]

cougarman what was the setup on that motor always wondered what Cubic inch and turbo size?

I just stumbled on this thread. X is real high for not having any power to spin a big diameter wheel. I’ve been there. I have a prop adapter for 19 spline small shaft to 26 big shaft. That will open up your prop selections. I would go down to at 1 below or even with the bottom and find a 17 diameter 3 blade that’s hasn’t been molested. My Super with a speedy 4 was 1 below and prop slip numbers were like 3% and ran over 100 with ease. Brett did my final 4 blade for me. Being I had over 900hp we did a 17.25 X 28 4 blade with the tips slightly rounded. Boat was like on rails. So much lift had to make a swept back skeg for the drive. Sad day when it went to a new home . Need info send me a PM

[QUOTE=Nickc919;4935883]The engine was a tall deck 572. The turbos were 75mm running 26 lbs of boost. A little over 1700 hp on 110 octane.

Thanks Zuper, that's very helpful. I'm leaning towards a 2" spacer. I think I'll start there and see what happens. Seems like no matter the power, I'm still pretty high. I don't know if I'll get around to putting the bigger motor together this winter so I may have another summer playing with smaller props and drive heights.

thats pretty insane. Always wanted to twin my 28 pantera just dk how it would act getting on plane but with that much power im sure it was fine lol

[QUOTE=check300;4938205]