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Old 06-07-2005, 09:37 PM   #1
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Smile explain props so I can go faster plse

Okay so i need to gain some speed on my mate.......tried chucking people overboard, removing all kit, even driving near naked but need to know about props.

So a 21 by 14 3/4. or a 21 by 14 1/4 assuming each move 21 inches through the water for every turn and i've got the old girl on full loud and in the rev range, whats the effect of a bigger diameter (the prop!).

Do some props get more of the boat out the water?

What about the make of the prop?

Ive got a Volvo SX leg and a 195 V6. Yep should have got the V8.

Captain Crawfish.
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Old 06-07-2005, 11:45 PM   #2
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To go faster you need more power rather then a better prop!
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Old 07-07-2005, 09:15 AM   #3
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Have a look at the link
http://www.mercurymarine.com/everyth...ut_propellers5
that will explain how they work.
you will need to know your gear ratio & RPM to calculate the performance difference, with regard to the dia of the props that will show the difference in the % slip, the calculation on works on pitch only. Bigger dia less slip (in Theory). It is just that
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Old 07-07-2005, 11:28 AM   #4
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If you're within your rev range when flat out, any advantage from props is gonna be small, unless your current prop is badly damaged.

you are already using all your hp, as it's not over revving (or under) and as it's a trimmable drive system, playing with the trim at WOT will make up for most prop types.

What prop is it that you currently run?

I would say, get some more Gee-Gee's if you wanna go quicker.

I'm sure they did a 200+ hp version of the 4.3 V6, find out what the diference is (in engine spec) as it may be pretty simple to upgrade the motors power.
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Old 07-07-2005, 11:41 AM   #5
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Quote:
Originally posted by Jon Fuller
[BI'm sure they did a 200+ hp version of the 4.3 V6, find out what the diference is (in engine spec) as it may be pretty simple to upgrade the motors power. [/B]
Just dont go asking Volvo how to increase HP on a v6 they kinda laugh in your face.

I got some joy with an american custom car co. as thats another yankee block innit?
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Old 07-07-2005, 12:03 PM   #6
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you need the microficshe, just compare part No's of stuff like cam, valves, etc.
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Old 10-07-2005, 02:55 AM   #7
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Re: explain props so I can go faster plse

Quote:
Originally posted by willfree
Okay so i need to gain some speed on my mate.......tried chucking people overboard, removing all kit, even driving near naked but need to know about props.

So a 21 by 14 3/4. or a 21 by 14 1/4 assuming each move 21 inches through the water for every turn and i've got the old girl on full loud and in the rev range, whats the effect of a bigger diameter (the prop!).

Do some props get more of the boat out the water?

What about the make of the prop?

Ive got a Volvo SX leg and a 195 V6. Yep should have got the V8.

Captain Crawfish.
Yes every prop is diferent, get one worked for your need, more bow lift etc etc.
give prop revolutuons a call for more help
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Old 10-07-2005, 09:33 AM   #8
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Hey burty have you got prop revolutions number?
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Old 10-07-2005, 09:42 AM   #9
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Old 10-07-2005, 11:00 AM   #10
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Quote:
Originally posted by scottyboy
Hey burty have you got prop revolutions number?
yup

Quote:
Originally posted by roofer
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Old 11-07-2005, 05:31 PM   #11
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you can use a rule of thumb formula, 1" of diameter or pitch will relate to 200-250 revs on your engine. give us a ring on 01252 316412 for more info
regards
Geoff
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