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Old 11 September 2006, 05:51   #1
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Hypothetical (and daft) idea

What would happen if you filled the tubes on a RIB with helium?

Surely as you would get "lift" from the tubes there would be less drag in the water and performance would improve?

Not that I have any helium, it was just a moment
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Old 11 September 2006, 06:05   #2
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i have often though the same usually after the fluid stuff !

would you not have to work out the volume of the tubes and then the amount of lift that would be created by said volume of helium deducted from the overall gross weight then what ?

Andy
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Old 11 September 2006, 06:38   #3
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Quote:
Originally Posted by BogMonster
What would happen if you filled the tubes on a RIB with helium?
You would be wasting a lot of expensive gas. Helium in the UK costs about 1p per litre. Do some sums to see how much you would need to inflate your tubes. Then how are you going to keep it in? Helium being much lighter will leak out past the valves and through the tube seams even if they are tight enough for Nitrogen.

If you want to go faster you need more power or less weight, so fewer pies

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Old 11 September 2006, 06:50   #4
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I just did a back of envelope calculation:

25 cm radius tubes, 6 m long on each side of a boat is about 2,350,000 cm3 of gas.

With air - this weighs roughly three and a half kilos. Helium therefore can save you no more than 3 kg! Even if you could keep it in your tubes.
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Old 11 September 2006, 07:55   #5
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I guess there could be an argument for using nitrogen though, same points as using nitrogen on car tyres.
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Old 11 September 2006, 08:02   #6
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I guess there could be an argument for using nitrogen though, same points as using nitrogen on car tyres.
Mat, most of use are already using 79% Nitrogen
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Old 11 September 2006, 08:11   #7
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One advantage of Helium is that you can detect leaks easier . Everyone starts talking like "Chip and Dale" (Chipmonks).
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Old 11 September 2006, 08:22   #8
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I once filled a SIB with expanding foam (stuff builders use), worked a treat and stopped all the leaks.
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Old 11 September 2006, 08:27   #9
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I heard old spice is filled with a mix of CH4 & various sulphides.

Quote:
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Mat, most of use are already using 79% Nitrogen
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Old 11 September 2006, 08:31   #10
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I heard old spice is filled with CH4
Nah, it's a very efficient clean burning diesel running on Haslar Marinas finest red Mephane might be useful to cook on but I don't have a stove on O/S. How do you get on with it in Distant Fumble ?
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