Tube Pressure

Andy Moore · 29 April 2006, 12:11

Getting the right pressure in the tubes is vexing me!

When the boat is at rest, the tubes seem to be about the right pressure. Perhaps they are a little bit on the soft side but we are are cautious about inflating them too much in case the dark tubes heat up.

As it is, when we get motoring the cold water and passing wind seem to have the effect of cooling the tubes and lower the tube pressure even more.

Should we simply be pumping the tubes up more when at rest?

codprawn · 29 April 2006, 13:45

Don't over pressure them - just think - which is easier to burst - a balloon that is a bit saggy or one that is pumped to the max?

Having said that the pressure relief valves should vent off if the pressure builds to much.

Alice · 29 April 2006, 13:49

Mine are the same, taught when the sun is out and soft at night.

BogMonster · 29 April 2006, 15:06

I have the same problems - and mine don't have pressure relief valves fitted, Humber say I could retro-fit them and they would supply them but I am not that keen on cutting holes in my tubes! got enough already

but I would be much happier with relief valves fitted and would definitely specify them on a new boat

anybody know what pressure most relief valves will blow off at??

Nick Hearne · 29 April 2006, 15:42

5 pints of Bitter dose it for me!

Jeff Pike · 30 April 2006, 10:25

Quote:

Originally Posted by BogMonster

I have the same problems - and mine don't have pressure relief valves fitted, Humber say I could retro-fit them and they would supply them but I am not that keen on cutting holes in my tubes! got enough already

but I would be much happier with relief valves fitted and would definitely specify them on a new boat

anybody know what pressure most relief valves will blow off at??

I bought new from Humber last year. Got dark blue tubes. Humber told me they recommend pressure relief valves on blue & black tubes as the darker materials absorbed heat quicker. Optional on other colours as they did not heat up as quickly. Didn't make much sense - might take longer to get 'up to temperature' but will still get there in the end. I do find that if the tubes get hot and 'let off steam' they often need pumping up again next time around. That bit does make sense - blow off hot air - less left in the tubes - cools down - goes soft .... a bit like .... no lets not go there.

Millermob · 30 April 2006, 10:37

we've had two new avon adventures now, obviously with dark blue tubes but do not come with pressure relief valves, which really is surprising and i don't think you can get them as an extra. Maybe their fantastic reputation with tubes means they can withstand it. Anyone know if they do do them?

Cheers Freddie

BogMonster · 30 April 2006, 11:46

Quote:

Originally Posted by Jeff Pike

I bought new from Humber last year. Got dark blue tubes. Humber told me they recommend pressure relief valves on blue & black tubes as the darker materials absorbed heat quicker. Optional on other colours as they did not heat up as quickly. Didn't make much sense - might take longer to get 'up to temperature' but will still get there in the end. I do find that if the tubes get hot and 'let off steam' they often need pumping up again next time around. That bit does make sense - blow off hot air - less left in the tubes - cools down - goes soft .... a bit like .... no lets not go there.

The logic in not fitting valves to light coloured tubes is flawed in some cases though, like in my boat which has orange tubes (all RIBs should be orange in the same way all Jaguars should be British Racing Green) but a large proportion of the inside part of the tubes is covered in a black reinforcing patch for divers etc to sit their butts on, and guess which bit gets really hot sitting in the sun! I notice a huge difference in tube pressures between calm sunny days and cold windy ones and its a friggin nuisance when I had it in the water if I went for an early morning spin, had to pump it up and then let it down again when I got back! So my boat has "light tubes" but also has "very dark tubes"....

Andy Moore · 30 April 2006, 14:14

Quote:

Originally Posted by Millermob

Maybe their fantastic reputation with tubes means they can withstand it. Anyone know if they do do them?

We have one of the little grey Avon tenders and we have always pumped it up as hard as it will go. I even stand on the pump to get that last little bit of air in to it! We have never had any leaks or splits with it.

wavelength · 30 April 2006, 16:28

would always spec pressure relief valves- we have them on the black boats and the yellow one. If you leave the boat in the open as we have on holidays and the sun comes out later in the day its nice to know the tubes are not in danger of splitting. Happened to a certain inshore lifeboat years ago-left out in the sun and pumped up hard out on display on lifeboat day-split more than one compartment! An expensive mistake.

Rogue Wave · 30 April 2006, 18:30

I was building Zapcats last week and it might surprise you to know that they run those at 6 PSI in race mode and inflate to 5 fo test.

The general level of toob inflation is between 2 and 3 psi so pump em up to 2.4 at midday and you should be cool, pressure gauges aren't that dear so you could get one and see what the toobs reads when the soft/hardness concerns you

FWIT I tend to run my toobs at the lower end of the preesure spectrum, but that's just personal nuffing Scientific