Tube pressure

popeyethesailor · 30 April 2014, 19:34

So I got my new pressure gauge today and checked what I thought would be the right pressure 3-3.5 psi?
It was 1psi!! but is it me or my gauge but that feels pritty solid !!

tonymac · 30 April 2014, 19:52

Quote:

Originally Posted by popeyethesailor

So I got my new pressure gauge today and checked what I thought would be the right pressure 3-3.5 psi?
It was 1psi!! but is it me or my gauge but that feels pritty solid !!

Have you automatic release valves built into the tubes?

popeyethesailor · 30 April 2014, 20:39

TBH I am not sure Tony it's a Searider

tonymac · 30 April 2014, 20:57

Quote:

Originally Posted by popeyethesailor

TBH I am not sure Tony it's a Searider

My Humber has release valves alongside the valves where you pump up the tubes. They actually look the same. So when the pressure gets too much they simple release. I never measure the air in my tubes. I just pump them up and when they seem hard enough I stop - bit like pumping up your bicycle tyres, never measure the pressure there either.

bartiny · 30 April 2014, 20:58

Quote:

Originally Posted by popeyethesailor

So I got my new pressure gauge today and checked what I thought would be the right pressure 3-3.5 psi?
It was 1psi!! but is it me or my gauge but that feels pritty solid !!

I have recently fitted leafield A6 pressure relief valves to my Humber SIB set at 3.25 psi I then pumped my tubes until the valves started to blow off and to be quite honest I was amazed at how hard it was to achieve that pressure with my foot pump (I think a Bravo 8) and the tubes felt really hard I have never in the past had them feel that hard.
So to me at least 3.25 psi in the tubes feels alot harder than I would have expected, cant wait to test it now.

HTH.

Fenlander · 30 April 2014, 21:07

Yes tubes can feel quite firm at 1psi... if you don't have a gauge they might seem OK.

When up to 3psi give or take which is common for most SIBs flicking the tube with your finger gives a distinct taught "drum" note which I use as a rough check when I'm on the water during a long day out.

At 1psi this note is a lot more dull sounding.

popeyethesailor · 30 April 2014, 22:28

Thanks for that, re the relief valve by the sound of it they are not part of the inlet valve so there for I don't have relief valves,
And it also sounds like my gauage is correct!
With my tubes being 19 years old and although good condition and I being over paranoid!!! thinking that 3.5 psi may cause a joint to blow?
What is the harm running them under the recommended pressure?

bartiny · 01 May 2014, 08:17

Quote:

Originally Posted by popeyethesailor

Thanks for that, re the relief valve by the sound of it they are not part of the inlet valve so there for I don't have relief valves,
And it also sounds like my gauage is correct!
With my tubes being 19 years old and although good condition and I being over paranoid!!! thinking that 3.5 psi may cause a joint to blow?
What is the harm running them under the recommended pressure?

My Humber SIB is MID eighties Hypalon it has probably been at 3.5>4.0 psi whilst out in the sun anyway (possibly more?), at least now I know that the blowoffs will protect any potential over inflation/pressure.

The Leafield A6 blowoffs are very easy to fit no glueing took me no more than 1/2 hour to fit all three. just got to be brave with the stanley knife

You can get a different values of pressure valves not sure on the actual pressure preset but I have seen 2.5 psi if you are worried.

HTH

skytour · 29 May 2014, 13:26

Check with manufacturer on pressure recommendations. The recommended pressure for Protector RIBs is 2.8 lbs. which produces a distinct drum note when flicted with a finger. Contrary to common wisdom, under inflation is the most serious condition for damage to RIBs, especially if undergoing rapid maneuvering. Rear seam failure is common in this situation. In addition to following manufacturer inflation recommendations, Lifeline (factory repair station) here recommends ¨bullet plates¨be installed to further protect the rear area of the tubes. This is particularly important in a RIB like ours that can obtain WOT speeds of 60-65 kts.

Harrys Game · 29 May 2014, 13:49

"This is particularly important in a RIB like ours that can obtain WOT speeds of 60-65 kts"
Thats not a rib its a plane! Regards Jim

IanT · 29 May 2014, 14:21

Am i right in thinking the 3psi (or whatever the limit is for your model) will take account for the changes with sunlight?! I have black pvc tubes and they go from quite solid feeling to quite slack between a sunny day and nighttime at this time of year!!