Do extension boxes pickup speed on Fountains?
04-12-2008, 11:22 PM
#11
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Every boat that I have been on that had boxes put on, ran slower but handled a ton better.
Alot of the time folks end up over analyzing things. If you sit down and think, common sense can answer alot.
When I think of boxes I think slower because the prop is not up under the ass anymore, and more leverage for the same reason - the prop is further back. Could be totally wrong but that is what I think of.
Alot of the time folks end up over analyzing things. If you sit down and think, common sense can answer alot.
When I think of boxes I think slower because the prop is not up under the ass anymore, and more leverage for the same reason - the prop is further back. Could be totally wrong but that is what I think of.
04-13-2008, 07:37 AM
#13
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boxes do work.
so do blade , diameter, pitch, and ring changes.
the biggest improvement will come from a good c.g .
boxes fail due mostly in part of the c.g .
you cant change prop pitch upwards without adding more power, thus you cant move the point of leverage without effecting the c.g . too many people spend bucks on big ticket items with poor results as said above simply because of info.
as for the whipples, and i am assuming the new 5 litres. they work fantastic on the 525's depending on configuration they will make over 1000 h.p . my friend mr. sgro has em on a set of engines, boat went from 107 or so to almost 140. huge difference. engines now have 60 hrs i believe with no failures and run like kittens at idle.
so do blade , diameter, pitch, and ring changes.
the biggest improvement will come from a good c.g .
boxes fail due mostly in part of the c.g .
you cant change prop pitch upwards without adding more power, thus you cant move the point of leverage without effecting the c.g . too many people spend bucks on big ticket items with poor results as said above simply because of info.
as for the whipples, and i am assuming the new 5 litres. they work fantastic on the 525's depending on configuration they will make over 1000 h.p . my friend mr. sgro has em on a set of engines, boat went from 107 or so to almost 140. huge difference. engines now have 60 hrs i believe with no failures and run like kittens at idle.
04-13-2008, 08:11 AM
#14
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I have boxes behind 525sc and they did nothing but helped handeling. the boxes are mounted as high as they can , and with this and the swim platform when the drives are tilted out they hit the swim platform. not good. I think with the boxes mounted as high as thy can and -2 shorties I would pick up as much as 5mph. But a new boat looks more impressive than spending money on a used one.
04-13-2008, 09:08 AM
#16
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Center of gravity.
When you push the props farther back, they're grabbing "cleaner" water, and they need to be raised, otherwise you'll be "dragging" them in the water cause they're way too deep. That's why most of the time when boxes are added, the props are not high enough, and you will see a loss in speed. But like mentioned previously, they do work when installed correctly.
When you push the props farther back, they're grabbing "cleaner" water, and they need to be raised, otherwise you'll be "dragging" them in the water cause they're way too deep. That's why most of the time when boxes are added, the props are not high enough, and you will see a loss in speed. But like mentioned previously, they do work when installed correctly.
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Chicago Powerboat Club Director
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www.chicagopowerboat.com
04-13-2008, 10:18 AM
#17
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a good analogy to boxes and leverage effecting c.g and running attitude would be to try and pull a nail from a 2 x4 using a claw hammer but holding the handle at different distances from the head of the hammer effects how easy you can pull said nail.
same relation to the drive pulling the bow up.
as for sgro send me a p.m with your number.
