Need some advice/feedback (RIB - R)

[Mr-d]

Hi, we just bought a Corsair Domar Inflatable boat (with inflatable keel)

It looks like a rib, it performs similar to a rib, so i just call it a rib, even though there is not a single piece of fiber glass on it.

Anyway, i was wondering, since the tubes are similar to a normal RIB, what pressure should be put onto it? I have no idea how far i can go, as we have a compressor that can go up to 8BAR, and i chicken out long before 3 bar.

Also, has anyone successfully Coated an inflatable with Fiber Glass?

Ill go and take a pic of it now, will post later.

Thanks,

Daniel.

[Manos]

Is not presure you should be thinking but volume.
Presure should be about 2bar max I think.

[Mr-d]

Sideview
Back view
No view of the front right now, camera ran out of battery, and the flash decided that it was to dark to take a pic, so lit up the front end of the trailer.

Pics are about 500Kbyte each, 56K beware.

[Mr-d]

Originally Posted by Manos

Is not presure you should be thinking but volume.
Presure should be about 2bar max I think.

Well, i have no idea how much volume goes into the tubes, however there is a stage where it is *full* and you can continue filling it up after that.

How would you measure the volume entered?

[Tim M]

For a Quicksilver inflatable with inflatable keel its 250mbar (3.5psi)

(Is 250mbar 2.5 bar?? )

Manos, what do you mean "it's volume not pressure"; pressure will increase as volume does...

Pressure is the standard measurement of tube hardness round' here!

[Jackwabbit]

Avon recommend 3 to 3.5 PSI that’s 0.2Bar to 0.23Bar, we have an Avon CRRC520 which has a flexible floor. This would wallow all over the place with 6 diver on board, so I contacted Avon to see what the pressure should be & they gave me the figures above. The only time we pumped it to 3PSI the boat just touched a breakwater; there was a huge BANG with the result of a 3ft split down one side. The sudden loss of pressure in one chamber resulted in the baffle cone in the next chamber splitting and loosing air from the whole of one side of the boat. Now we only pump it until its firm not hard, so please be warned DON’T pump it too hard.

[kitten]

Originally Posted by Manos

Is not presure you should be thinking but volume.
Presure should be about 2bar max I think.

As 1 bar (being atmospheric presure ) is about 15 psi, you must have just voided any warrenty you had on your tubes by blowing them up to 30psi.

If your boat is fitted with good quality valves then apparently if the top is not sealed they will realease presure over about 11psi anyway.

[Tim M]

A local Avon dealer once told me that you should pump them up so you can still stick your finger in an inch. I tried this, but they were whey too soft. 1.2PSI works well on the RIB.

Tim

[Rupert Bear]

Depends on what you are using them for, recommendations are usually around the 2-3psi mark. 30psi is just a tad much!
If you have folk sitting on the tubes then 3psi is a bit hard as they end up bouncing up and down on the tubes with every bump.

[Jari Hjerppe]

should be correct pressure for your boat. In RIB pressure can be lower, around 0,12-0,2 bar, but SIB needs harder tube to keep the boat in shape.

Do Not use compressor to fill your boat unless you have accurate pressure gauge attached to the system.

The tube should be hard enough when you can't bend the cone in the end of the tube.

Jari

[codprawn]

Pressure readings are all well and good - it's the feel of the tubes that count - you don't want them as tight as a drum - just firm will do - better too little air than too much!

[ribraff]

I agree with Codprawn on this one, go by feel and experiment, if i'm in a rough sea i let some pressure out as this softens the impact of big waves on the tubes and makes for a smoother ride

[Mr-d]

thanks for the feedback guys,

So the answer is basicly, "Whatever you feel you want to put in it."

i think im running it at 2bar now, can probably press the sides in about 1CM with my thumb... May i just add that this is not a "normal" rubber boat with normal rubber, it think it's 4 layered with canvas reinforcement.

The valves are emm, "Bridgeport - Made in italy" and i cant find anything of them on internet either, however i think if something would blow, the valves would just jump out as they are only some sort of rubber/plastic, and when you inflate the boat you can see them slowly popping up out of their sockets and go into oval shape.

Since i live on the west coast of scotland, and dont really like getting wet, i only go out on nice-ish days. however i have already done approx 1M waves with it, and the nose tends to flop up when it hits a wave to hard, resulting in whatever was in the front, lying in the back in less than 1 second. (even tied down stuff) so i guess the harder, the better in my case, as there is no solid hull, the front tends to bounce when it hits larger waves, (the more speed, the less you notice it anyway )

Thank you

[Scary Des]

Originally Posted by Mr-d

................i think im running it at 2bar now..........

I still think you should only using 2psi(pounds per square inch) not 2 Bar (29psi). Are you mixing your measurements

When we used to use this type of boat it paid to blow the keel tube up as much as possible but to leave the tubes a bit softer, made it faster and more comfortable


Des

[Mr-d]

If i only inflate it a tiny tiny bit, so that it is just round, the boat is all floppy and will literally fold round and go sideways like a snake upon each encounter of a wave. I dont know that it is actually 2 bar, but i think it is really close to it, i can attempt to measure it if i find a way to do so... i dont have a gauge that fits that size. i just went out (nice sunny day...calm water)i head out past the point.. and guess what, waves are approx 1M high, 3 people in the boat, me wearing my trousers and tshirt.... got absolutly soaked!, the nose does not fold round now, but there is quite a bit of pressure in the tubes, and it does not really jump upon hitting the waves. it just glides over them, and nose digs into next wave that is about to break on the front end (result, me soaking wet.)

Manos, imagine a long tube shaped balloon filled with water, and then imagine you attempting to push/steer it from the back... Now that image is what the boat is when it is just round, and going somewhere with some waves.

I know i shouldn't compare this to car/bicycle tyre pressure, A car does approx 40PSI and a bike does 50PSI, the tyres feel harder than the tubes, so through some Guestimation, id say im running close to 30PSI on the inflatable keel,and slightly less on the nose and sides (~25 psi) If only i had an adaptor to hook it up to a gauge.

[Manos]

Is this a wind up or what??

[Jari Hjerppe]

You are right. You shouldn't compare bicycle or car tyres to the tube of your boat.

Think about the diameter and construction of the car tyre compared to the boat tube. Boat tube feels very hard when pressure is near 0,3 bar. Pressure reliefe valves that are used in inflatable boat collars activates when pressure reach 1,75-3,25 PSI (different valves for different reliefe pressures).

Jari

[Robert1]

Originally Posted by Mr-d

The valves are emm, "Bridgeport - Made in italy" and i cant find anything of them on internet either, however i think if something would blow, the valves would just jump out as they are only some sort of rubber/plastic, and when you inflate the boat you can see them slowly popping up out of their sockets and go into oval shape.
Thank you

Mr-d,

The fact that the valves are being deformed and popping away from the tubes would suggest that the boat is perhaps over-inflated?

Robert

[chrisallse]

You sure it's not Mr Bean?

[Tim M]

Mr-d, can I recommend the purchase of a correctly fitting pressure gauge...