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PropShaft Centerline

Old 07-29-2014, 09:14 PM
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What do you guys have for prop shaft height ? wondering about boat lengths compare to shaft height
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Old 07-30-2014, 12:55 AM
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2-6 inches below the bottom on most single engine boats. It depends on if its a stepped hull, how much hp and how big of boat.

A 29 non step with 500hp is going need to be a lot deeper than a 29 stepped hull with 800hp.

Deeper gives more leverage to carry the bow and reduce the wetted surface. Stepped hulls don't need to carry the bow as much.
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Old 07-30-2014, 08:33 PM
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29' Scarab, twin 383,s 400hp/425tq ,,,, less than 5' of boat in water at WOT
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Old 08-04-2014, 10:35 AM
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Originally Posted by 01scarab29
29' Scarab, twin 383,s 400hp/425tq ,,,, less than 5' of boat in water at WOT
she ought to run good with that power? what is you r reason for asking? are you considering 2 inch shorties?
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Old 08-04-2014, 08:05 PM
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Originally Posted by hullofjustis
she ought to run good with that power? what is you r reason for asking? are you considering 2 inch shorties?
Run's 73mph with a 25p mirage ,,,, reason is I'm thinking tremendous drag,,,, I'm 7 1/4' below hull ,,, I am thinking shorties,,,,,, THOUGHT's ,,,,,
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Old 08-07-2014, 06:07 AM
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Originally Posted by Griff
2-6 inches below the bottom on most single engine boats. It depends on if its a stepped hull, how much hp and how big of boat.

A 29 non step with 500hp is going need to be a lot deeper than a 29 stepped hull with 800hp.

Deeper gives more leverage to carry the bow and reduce the wetted surface. Stepped hulls don't need to carry the bow as much.
is that 2-6 inches below hull where drives are, or below lowest point at keel? edit; ok, that is single engine spec. well, question still valid for his twin engine scarab. 7-1/4 inches sounds a little deep to me.

Last edited by dereknkathy; 08-07-2014 at 06:13 AM.
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Old 08-08-2014, 09:41 AM
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the black hawk drives on p29 were shorter drives than a bravo 3 and that boat ran great speeds with minmal power i would recommned shorties
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Old 08-08-2014, 10:11 AM
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No extension box correct?
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Old 08-08-2014, 11:08 AM
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i would try the shorties first and see what you get. if you don't like the results or want more then go with an extension boxes i put 3 up imco boxes on my panther and had to change the engrine mount location, so unless you have to pull an engine i would wait on them.
i would be very interested to see how yours runs with shorties. i set my panther up to be 1 1/4 below the bottom with shorties and 3 1/4 with standard length with the 3 up boxes
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Old 08-08-2014, 04:38 PM
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correction, runs 73mph with 23mirage plus,, run 25 on long poker runs for better cruise, measurment is inline with drives ,, i am wanting to buy shorties, prefer case only ,, would like -3, thinking i can always add ,, ,,,, also has anyone with twins run props inward ? thoughts ?
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