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Old 11-24-2004, 01:07 PM
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Default Re: How much faster

RLW, the 93+ mph Pantera was a 1999 24' 7' beam 3800+/- lb boat with (I dont remenber exactly, been a couple of year since I owned it) 625-640hp 460ci procharged intercooled engine built by Proroc. Would spin a tweaked 29p Mirage (not mirage plus) at about 5600 rpm to a best speed of 93.4 on GPS. Boat would consistently run in the 89-91 range. Most fun I ever had with a boat. Tricky driving at those speeds in that boat. Unfortunately for the gentleman that bought it from me, I dont believe his experience was as pleasant.
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Old 11-24-2004, 03:30 PM
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Default Re: How much faster

Originally Posted by scarabman
Unfortunately for the gentleman that bought it from me, I dont believe his experience was as pleasant.
ok THATS TOO SHORT for a long story, whats up Scarabman, somebody get seasick?
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Old 11-24-2004, 07:51 PM
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Default Re: How much faster

Originally Posted by aero-offshore
ok THATS TOO SHORT for a long story, whats up Scarabman, somebody get seasick?
What happened, Scarabman????

Is it similar to this story?
A fellow I met a few years ago at Shades restaurant on this lake had just bought a Donzi 22 classic with a 502 mag, with a Blackhawk surface drive. It went into the 80's, apparently. He was white when I first met him at the restaurant, and he could not sit down.

He had been hotrodding around, and happened to hit one of those stealth cruiser wakes. He said he was maybe 15 feet in the air before he could blink, and was looking down at the water when the boat was about 90 degrees to the water! It landed hard on it's side, but did not flip. He said he was selling the boat right then. He was bruised up, but not that bad...
If only I had a check with me then....

I hope your story was not that bad...

Kent
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Old 11-24-2004, 10:07 PM
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Default Re: How much faster

I read somewhere that a 38' awesome gained speed and cracked the century mark with stock Hp power by using 1.5 bravos and 34 or 36 bravo props instead of the 1.36 they started with. I did some testing many years back with a 19' boat with 1.32 vs 1.5 ratio alphas and the 1.5 with a bigger prop was 4 mph faster at the same rpms. Torque is what boating is about, a 600 hp na 454 will usually not beat a 500 hp na 540 in a boat.

Last edited by IRONMAN; 11-25-2004 at 08:54 AM. Reason: Correct ratio stated.
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Old 11-24-2004, 10:35 PM
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Default Re: How much faster

Originally Posted by Pat McPherson
Hey Ironman,
Hey you have done a little prop testing on your boat...?
My labbed 26p Bravo pushes my boat 1mph slower than my 25p Mirage+.
How is that Bravo conversion going?

Buck, do a search on drive ratios here in Tech Q&A. The subject has been talked about a lot...
From what I remember reading, with all of the prop available, only boats that crack 100mph benefit from a 1.36 ratio.
I also remember reading that a 25p prop is about the most efficient pitch for the type of props we run. A 26p Bravo I measures 24.5 and a 25p Mirage measures 25...
Pat I have found on the Pantera and Donzi classics the plain Mirage, Hydromotive 3 blades, and cleavers to measure or act like true pitch. The Mirage plus seems to be about 1" bigger than listed and the Bravo1 4 bl seems about .5" smaller than listed. On one test day the Labbed Bravo1 26 ran .5 mph slower than the stock Mirage+25 and the stock Mirage+ 27 was .4 faster than the 25 but handling, acceleration, and rpms were lost. It wasa poor test day though 93 deg and dead flat water. I think that on rough water with a more neutral prop(like a 3 blade) and neutral trim the Mirage will be closer to 1mph faster like you observed. Oh yea the transom assembly is on at 17.625 X and I found the Bravo to be more than 2 inches shorter than the TRS so I actually Lowered my X slightly to keep the bow carrying abiliy of the drive. Jo said that over 18 I would probably be looking for a spacer to go back down so I settled on this. Chris
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Old 11-25-2004, 04:11 AM
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Default Re: How much faster

Although it is really the Member's who bought the boat from me story to tell, he developed engine gremlins very shortly after purchasing the boat from me. He went through a couple of re-builds before successfully defeating said gremlins. Once that was all said and done, he never really, to my knowledge, got the hang of driving that boat with that kind of hp. I dont know the exact details, but I know his wife was washing underwear with skid marks on a regular basis. After awhile it seems he just got discouraged and kind of gave up. To his credit, he asked all the right questions, and as far as I know tried all the right things, I just dont believe it was the right boat for him. Not a boat power combination meant for very many people.
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Old 11-29-2004, 08:37 AM
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Default Re: How much faster

Rolling cruiser wakes are killers, Scarabman, that boat must have been some wave jumper Thanks for the story.
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