tube pressures

BogMonster · 01 August 2006, 01:32

How do you measure tube pressure?

Mine (Humber Destroyer) doesn't have pressure relief valves so I probably have it softer than it should be most of the time, with the problem I have had I am paranoid about it going bang!

There is a sticker on the console saying the pressure should be 2-3 psi but I don't know how you can measure them - the design of the inflation valves means that you can't stick a gauge on - even if I took the inflation tube off the pump and made an adaptor to fit a gauge to the other end of it, it looks like the valves are forced open by air pressure from the pump and then close off after each stroke, so it isn't like a tyre valve where once the airline is connected the valve stays open until it is disconnected and you can measure the pressure with an external gauge.

I suppose once you get a "feel" for what the maximum recommended pressure feels like when you poke the tube with your finger then you don't really need a gauge but at the moment I don't really know what pressures are in them, I just sort of inflate it to "firm-ish" on the day but I think they should probably be harder than they are as they do move quite a bit when you hit the bumps!

Sorry another thicko question from me but there must be an obvious answer I am missing, how do you do this is there a special gauge of some sort that opens the pressure valve when you stuff it in the hole, or is it all just guesswork?

Thanks

Edited to say I just did a search (ok ok I know ... I should have done it first...) - does anybody know how much the special gauges from Humber etc run at?

I still wish it had relief valves though...

codprawn · 01 August 2006, 02:06

Tubes don't need to be drum tight on a RIB - on a SIB maybe. Remember the harder you blow up a balloon the easier it is to burst!!! The softer the tubes the more shock they will absorb.

gaviotapete · 01 August 2006, 03:37

do you lose alot (5-7knots) of top speed if they are too soft? in other words, how soft is too soft?

Christopher · 01 August 2006, 10:07

[QUOTE=BogMonster] How do you measure tube pressure?

This will do the job. Fits into any standard valve(Leafield, Halkey Roberts etc)

Can be ordered at following link www.henshaw.co.uk

jwalker · 01 August 2006, 10:28

When my valves blow off, leaning on the tube with my knuckles deforms it but it feels very firm. It depends how loaded your boat is but my Destroyer gave a noticeably softer ride with the tubes soft but it was less stable in the waves. If your boat is light and the tubes are not in the water, it'll likely not make much difference.

BogMonster · 01 August 2006, 10:59

[QUOTE=Christopher]

Quote:

Originally Posted by BogMonster

How do you measure tube pressure?

This will do the job. Fits into any standard valve(Leafield, Halkey Roberts etc)

Can be ordered at following link www.henshaw.co.uk

Thanks - I get "page not found" from that link?

jwalker's description is about the point when I start worrying about mine on a sunny day so it sounds like I am not too far out but will try and get a gauge anyway for peace of mind.

I'd rather have relief valves but fitting those is just toooo much work - there must be a market for a relief valve that you can just screw on to the outside of a standard valve, and will open the normal valve, seal around it and then vent any excess pressure through a blowoff valve. Wouldn't be at all hard to make one.... you can pop a cheque in the post for the royalties, ta

Christopher · 01 August 2006, 11:34

[QUOTE=BogMonster] [QUOTE=Christopher]

Thanks - I get "page not found" from that link?

Appears to work this side of the world!!!!

Try this which should take you straight to the accessories page where the item is listed.

http://www.henshaw.co.uk/default.cfm/loadindex.7

BogMonster · 01 August 2006, 11:36

cheers - the interweb is doing some odd things this morning....I think the pigeon is on strike or something

codprawn · 01 August 2006, 16:54

[QUOTE=BogMonster]

Quote:

Originally Posted by Christopher

Thanks - I get "page not found" from that link?

jwalker's description is about the point when I start worrying about mine on a sunny day so it sounds like I am not too far out but will try and get a gauge anyway for peace of mind.

I'd rather have relief valves but fitting those is just toooo much work - there must be a market for a relief valve that you can just screw on to the outside of a standard valve, and will open the normal valve, seal around it and then vent any excess pressure through a blowoff valve. Wouldn't be at all hard to make one.... you can pop a cheque in the post for the royalties, ta

That is a VERY good idea - you should approach someone like Halkey Roberts or similar. You have aired the idea here so you already have some form of protection. Having said that it is very rare to find something nobody has thought of before.

BogMonster · 01 August 2006, 20:32

[QUOTE=codprawn]

Quote:

Originally Posted by BogMonster

That is a VERY good idea - you should approach someone like Halkey Roberts or similar. You have aired the idea here so you already have some form of protection. Having said that it is very rare to find something nobody has thought of before.

No doubt Sc**pion Racing are copying it as I type then (allegedly)

I would be happy if I could just buy such a thing - though I don't know how many different types of valves there are? If you had the wherewithal to mould plastic, then it would be so easy to make - I bet you could sell them for less than a tenner each and my order would be at the head of the queue

the option is to cut five holes in my tubes and break out the glue, and I am not confident enough to jam a sharp knife into my RIB in every chamber

BogMonster · 01 August 2006, 20:40

I am going to pursue this idea with whoever makes the valves...

What type of valves does a Humber use? I wouldn't know a Halkey Roberts if I tripped over one

Selfishness leads me to start with ones that might fit my boat