Props in or out on a trip
01-09-2006, 08:25 PM
#11
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Re: Props in or out on a trip
Was this a Larry Smith Scarab?? If so look him up and give him a call. Heck it might be worth a call anyway..... Someone on here will have his contact info.
01-09-2006, 09:01 PM
#13
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Re: Props in or out on a trip
It's not a Larry Smith it's just a standard Wellcraft. I have Larry's contact numbers thankyou. I don't live in Detroit I'm in N.Carolina. Has for the measurements rpm's currently 5200-5300 I want to turn 6000 gear ratio is 1.5 the toe is set at .062" per side in I have tried it out no noticable change. Set back, I'm not at home I'm in Daytona testing soit & the rest of the measurements I don't have with me. With a trip does props out help with transom lift?
01-09-2006, 09:05 PM
#14
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Re: Props in or out on a trip
Originally Posted by bjlesl
Gentlemen I was hoping someone could give me some idea on props in or out. I have a straight bottom 43 Scarab with trip 850's & #5 drives & 17x31 4 blade props. The nose cones are roughly 3.5" below the running surface of the hull. I've tried raising the lowers 2" by removing the 2" spacer but that really didn't seem to help & the prop slip went into the 18% range. With the spacer back in the slip is in the 12% range. But the old girls heavy a** feels like it's just stuck in the water. It never really gets loosened up. Any help would be appreated. I have some big tube headers coming & have just installed 10-71 BDS blowers & plan to turn the boast up to 10 psi which should bump the motors up to 950-1000 each. By the way I'm at 92 on gps right now. Thanks.
your hull more transom lift.Also check toe in & out on you drives.3.5 " below the running surface seems deep.If you pull
the spacers out try a larger diameter prop.This should free
up the drag caused by the gear cases.If stand off boxes were added you could probably go higher.Talk to the factory about
what your trying to accomplish.92 Looks like about 5400 rpms
1:50 gears, more HP should give you the ride your looking for
Just my 2 Good luck!!!
01-09-2006, 09:12 PM
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Re: Props in or out on a trip
Thanks Hotpursuit. I just checked my prop slip calculator with the 2" spacer out I had around 18% slip now I'm in th 13.3% range. Which if I could turn 6000 that would be about 100 mph even. So if I understand you when I raise the drives I might need some larger diameter props.
01-09-2006, 09:17 PM
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Re: Props in or out on a trip
2 props can be hard to come by, let alone 3. put teague on the list of people to call about props too.
is your x-dim the same on all 3? is the skeg on the center? are the rpm's across the board? do you have a delta pad?
is your x-dim the same on all 3? is the skeg on the center? are the rpm's across the board? do you have a delta pad?
01-09-2006, 09:19 PM
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Re: Props in or out on a trip
Thats correct more blade in the water less gear case = increased MPH & less slip. I'm assuming you running cleaver
style wheels.
style wheels.
01-09-2006, 09:24 PM
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Re: Props in or out on a trip
Yes the X is the same on all 3 & yes the center drive still as the skeg. The rpm's are close enough to call them the same. I learned with my line of work tachs only good for 50-100 rpms & you can only calibrate them real close for only about a 500-1000 rpm range. I know the 5 boat that Gentry set the speed record in '93 had the skeg removed from the center drive although that was #6 drives.
01-09-2006, 09:44 PM
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Re: Props in or out on a trip
i guess if i was going to pull a set-up out of a$$ based on the above info; i would look to remove the center skeg, go up a size or 2 (engine dependent maybe +) use 5 blade large diameter props on the outside, remove the spacers on the outside only, turn the props out, use your current 4 blade (at first) in the center to allow min hull disturbance. obviously removing the center skeg would be the last move... i would keep the center a 4 blade and play with diameters and pitch after seeing if it liked the spacer removed.
