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Old 07 May 2004, 10:52   #11
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Yep, 19" is what I'd expect too.

Rat is not quite correct but I know where he is coming from. Reducing the pitch, at the same rpm, will cause the boat to go slower but you will benefit from higher revs. When correct, the benfit from higher RPM, and therefore power, will outweigh the loss from pitch.

Fuel economy will be ok because the engine will be working lightly on part throttle when cruising. You might find it sounds less grumpy too.

For diving, ie. load carrying, a bit low on pitch rather that high would be better.
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Old 07 May 2004, 11:00   #12
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Yep i was kinda right, this time last week i knew nothing about pitch or diametre, been trying to find a resonably priced prop for my engine, currently have an ali 11-1/2x19 and wanted to go stainless to a 21 inch pitch, the boats light and runs fast as it is just wanted to see if i could increase the performance and technically i could, problem is though that i cant get a 21 or 19 in stainless with a 11-1/2 cm diameter unless of course i want to have it shipped from Belgium or the states at that obviously increases the price.
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Old 07 May 2004, 12:11   #13
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Yeah, SS props do seem real expensive. As far as I can tell, I can't find any props for this engine in the UK. They are 14 * 25 and 13 * 25.

The postage from the US isn't too bad if you use the US Postal Service and not carries like Fed-Ex or UPS. I think to ship both props ( about 35lbs ) it will cost $100 for 6-10 day delivery. I guess a single prop would be around $60.
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Old 07 May 2004, 12:25   #14
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Yep I agree with JWalker - a lower pitch will give you more acceleration, therefore get you up on the plane quicker when the boat is loaded.

We get pretty good fuel economy revving about 3500, giving 30knots (ish).

David - I was working on the ePay team for 4-5 months back in 2001.

Ricky
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Old 07 May 2004, 12:30   #15
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Rich - I thought it might be you...... Are you still with IBM???

You doing much diving?
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Old 07 May 2004, 12:45   #16
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Dave - sent you a forum private message thing
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Old 07 May 2004, 13:05   #17
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i currently have a 21 on my 6.9 and am changing down to a 19 as we Solent and me want to have a play and decide what will suit her better for the work she does , i am leaning to the 19 more and more at the moment we will be doing this at ribx so come along and see what we come up with.
regards tim
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Old 07 May 2004, 14:13   #18
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Quote:
Originally Posted by daviesd
Yeah, SS props do seem real expensive. As far as I can tell, I can't find any props for this engine in the UK. They are 14 * 25 and 13 * 25.
Are you saying that different pitches are not available but different diameters are?

Quote:
The postage from the US isn't too bad if you use the US Postal Service and not carries like Fed-Ex or UPS. I think to ship both props ( about 35lbs ) it will cost $100 for 6-10 day delivery. I guess a single prop would be around $60.
My torqueshift prop came over from US at about 30 by UPS, albeit a while back.
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Old 07 May 2004, 14:17   #19
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Quote:
Originally Posted by daviesd
thats sort of what I am thinking - I don't think the Tornado's are particularly light. Although, it is kind of bizarre that it ran fine on the larger Ribeye.

I did notice that around the stern of the ribeye, it looks like it has a VERY pronounced step which might reduce its planing area - maybe???
The 6.5mtr Tornado is about half the weight of the 7.25mtr Ribeye.
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Old 07 May 2004, 14:48   #20
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Originally Posted by DJL
The 6.5mtr Tornado is about half the weight of the 7.25mtr Ribeye.
Don't tell him that. Now he'll be really peed off.
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