42 fountain straight bottom 100 mph
12-19-2009, 04:31 PM
#51
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I am willing to bet if you run the numbers on the new 40 epoxy Fountain race boats you will find they are as efficient or more efficient than mine. I have driven one with stock 525s and 6 drives at 102 mph without ideal props and set up. I am sure the boat with fuel and a driver and throttleman was atleast 8,200 lbs. I realize the formula is kinda generic and probably an average of some sort, but I wonder how accurate it is based on recent technology such as stepped hulls, superb props, ect ect. I am not just talking about Fountain , but Outerlimits, Cig, and other Manufacturers as well.
12-19-2009, 10:23 PM
#52
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The formula is generic but it works with any boat and any combination. If you know the weight, HP and top speed it will tell you the hull efficiency. Because it is mathematical, if you know any three, you can calculate/determine/predict the fourth. This is the formula:
Hull efficiency (220, 252, 275, etc)
__________ (divided by)
Total weight = MPH
_______ (the sq root of the total
weight divided by HP)
HP
This is what Mercury uses. I doubt they made it up, I believe it is SOP marine engineering.
It is pretty easy to see that many/most HP boaters spend way too time, effort and $ in the engine compartment.
On Monday, I will draw the formula, scan and post.
Ben
Hull efficiency (220, 252, 275, etc)
__________ (divided by)
Total weight = MPH
_______ (the sq root of the total
weight divided by HP)
HP
This is what Mercury uses. I doubt they made it up, I believe it is SOP marine engineering.
It is pretty easy to see that many/most HP boaters spend way too time, effort and $ in the engine compartment.
On Monday, I will draw the formula, scan and post.
Ben
12-19-2009, 10:45 PM
#53
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well I have it in my head with proper set up drive height and under 10,000 lbs with triple 700 hp (propshaft) I can go 100 think this sounds doable?
that would be a constant of 207
that would be a constant of 207
12-19-2009, 10:53 PM
#55
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Jesse,
I would expect you can go 100 MPH with lots of throttle left with 2100 HP. I don't know what the hull efficiency range is for any triple engine boat, but I expect it is greater than 207. Do you have any base line for what the hull efficiency is for a triple engine set similar to where you expect to be?
I would expect you can go 100 MPH with lots of throttle left with 2100 HP. I don't know what the hull efficiency range is for any triple engine boat, but I expect it is greater than 207. Do you have any base line for what the hull efficiency is for a triple engine set similar to where you expect to be?
12-19-2009, 11:20 PM
#56
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http://www.offshoreonly.com/classifi...o31817-en.html
this runs 95 stock with high altitude pullys on blowers
this runs 95 stock with high altitude pullys on blowers
12-21-2009, 09:32 PM
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How about doing a power conversion with a pair of turbine engines from www.ppsmarine.com. We are currently doing a power conversion on a 47' Apache with a straight bottom. Keep watching the site for build pics. www.PrinciplePropulsionSystems.com
12-22-2009, 09:20 AM
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http://www.offshoreonly.com/classifi...o31817-en.html
this runs 95 stock with high altitude pullys on blowers
this runs 95 stock with high altitude pullys on blowers
Spend a few hundred in the cockit to get the blue out with some white and done.
Last edited by Back4More; 12-22-2009 at 10:32 PM.
