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Old 28 August 2017, 02:53   #1
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RNLI D Class tube pressure, why so high?

Why do the RNLI keep their D Class at such high pressures?

Everyone I have ever seen, has always been absolutely rock hard.

I thought you were meant to have a slightly softer tube when operating in heavier conditions?
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Old 28 August 2017, 08:02   #2
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I'm guessing they have sort of figured out what works best!
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Old 28 August 2017, 08:20   #3
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The last thing you want when in the rough is a soft tube. Like trying to play snooker with a piece of wet string.
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Old 28 August 2017, 10:02   #4
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Another point may be that they do not want to have to top up the pressure when the boat is launched into cold water. All the D-Class boats I have seen have been stored ashore on a trailer.
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Old 28 August 2017, 10:04   #5
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Quote:
Originally Posted by Gobuchul View Post
Why do the RNLI keep their D Class at such high pressures?

Everyone I have ever seen, has always been absolutely rock hard.

I thought you were meant to have a slightly softer tube when operating in heavier conditions?
Possibly good advice for a RIB, but a slightly soft inflatable in rough weather is not a good combination. Also the definition of "soft" is often harder than people think. If you measure 2psi you'll find it's a fair bit harder than a lot of RIB tubes you encounter.
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Old 28 August 2017, 11:42   #6
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Sib wise the tubes have to be hard enough to withstand bending when they hit a desent wave or there's no point the RNLI arnt doing anything other than keeping them at the recommended pressure and in the controlled environment of the boat shed hitting cold water won't make that much difference when they go out I pump my boat up to the recomended pressure and that's it I don't touch it again no need unless it's winter and there has been significant temperature decrease to make them soft
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Old 28 August 2017, 17:58   #7
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Hi all

Could also use Nitrogen tubes topped up . No change in presure !
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Old 28 August 2017, 18:25   #8
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Hi all

Could also use Nitrogen tubes topped up . No change in presure !
Hmm... Air is about 78% nitrogen anyway, and just the same as air it's made up of molecules that whizz round more at higher temp, creating more pressure.

The laws of physics are pretty immune to marketing hype!
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