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Old 01 November 2007, 22:15   #11
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Hola Amanda

Seems you are having big trouble with inflation issues, will give the best remedy for it. Some previous data: Most inflatables dinghies, ribs, etc made of PVC or Hypalon have a MAX working pressure of 3.5 PSI or 0.25 Bar. It's virtually impossible that by finger touch you can obtain this reading, if you haven’t inflated a tube with a pressure manometer previously to confirm this reading by finger touch, will need a very sensitive finger to do so. Is like inflating your car tires at sight or finger touch, will have 4 different readings.

With ribs you cannot have poor boating performance when cruising with under inflates tubes as in normal inflatables dinghies because of the hard hull difference, tubes on this boat type are mere aestethic because they almost hardly touch the water, and if they do only a very small portion. So cruising with under or over inflated tubes won’t slow nor speed the boat as in traditional inflatables.

If you want to have all compartments inflated to the correct pressure in winter and summer get yourself a good pressure manometer that reads from 0 to 14 PSI or 1.0 Bar. About your inquiry if you are traveling from cold to heat, inflate all chambers to 2.0 PSI, at this reading you will feel the material hard at finger touch, while traveling the sun will do the rest inflating it to near 3.0 PSI or a little more. Don't you ever inflate to working pressure at sea level and take your boat to high mountains, you can blow the tube, example a tire inflated to 24 PSI at sea level will have 35 PSI at 3,000 meters high. Have not taken by boat to high elevations to make a comparisson, but the same pressure issues applies.

Have been using pressure manometers for the last 15 years, love traditional inflatables, which I sell. Never had a problem related to seems ruptures nor transom being unglued from the tubes, love the speed these boats can achieve being correctly inflated to their working max pressure which is 3.5 PSI.

In winter the boats are inflated prior to water launching to 3.5 PSI or 0.25 Bar, in summer, shade the boat first and inflate to max 3.0 PSI or 0.20 Bar, the sun will inflate the tubes a little more, or once on water check the pressure after about 15 minutes of sun exposure and deflate if necessary to working max pressure.

If the boat has automatic pressure relief valves forget all about all this pressure issue. Was purchasing Scoprega Bravo Manometers from Defender USA, sorry to say but are being delivered factory faulty, that is, have not precise readings and some will blow literally your boat because of over inflation, read less than what’s shown, so you will end inflating more passing the recommended max pressure; a real danger indeed. Won’t recommend foot pumps having a attached pressure manometers, they will give erroneous readings while pumping, are not exact, stay away from them. Best options can be electrical ones that adjusts air flow from 1.0 to 3.5 PSI. Or buy pressure manometers from Zodiac or Achilles brands and have a good machine shop make a precise valve adapter for the air valve your boat is presently using.

As to get an overall idea I work with Halkey Roberts Air Valves, a friend of mine who owns a machine shop (revolver machine) has made me this nice valve adapter, works marvelous well, would recommend you all to use pressure manometers, your boat tubes will be delighted being correctly inflated, all at the same working pressure.

If anybody would like to have/count/use a reliable pressure manometer, know a nice Korean Factory that produces/sells them, very cheap only US $ 6.50 each + shipping expenses, can ship via Fedex - DHL) worldwide. You will need to make the valve adapter if different, are being delivered to match Korean Halkey Roberts Valves (Gray Pin) , a bit different in diameter and pin height than American Halkey Roberts ( Yellow Pin) Just email me to send the person’s name who to contact and some photos of modified valve adapters using this manometer brand to get the idea.. Happy boating… Only 2 more months to our summer..yeah!!

Locozodiac
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Old 02 November 2007, 15:01   #12
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when I have picked up new boats from te toobers to deliver on to Revenger for Fitout I deflate the toobs and tie them up tight so they dount bounce about. Hey presto no prob's
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Old 02 November 2007, 16:12   #13
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Quote:
Originally Posted by Locozodiac View Post
Don't you ever inflate to working pressure at sea level and take your boat to high mountains, you can blow the tube, example a tire inflated to 24 PSI at sea level will have 35 PSI at 3,000 meters high. Have not taken by boat to high elevations to make a comparisson, but the same pressure issues applies.
I think you mean 30,000 ft (which is impossible to take your boat, or in practical terms a tyre to!). At 3000m the pressure difference (to sea level) is less than 5psi.
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Old 02 November 2007, 18:06   #14
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I think you mean 30,000 ft (which is impossible to take your boat, or in practical terms a tyre to!). At 3000m the pressure difference (to sea level) is less than 5psi.
Even so, a tube inflated to a max working pressure of, say, 3psi (or an absolute pressure of 17.7 psi) will certainly not like having the ambient pressure reduced from 14.7 to 9 psi. That would be the equivalent of staying at sea level and inflating the tubes to 8 psi (or at least trying to.)

I believe he was talking 3000 meters.

And, to be fair, tires go to 30000 feet pretty often (though, granted, not car tires...)


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Old 03 November 2007, 06:58   #15
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Even so, a tube inflated to a max working pressure of, say, 3psi (or an absolute pressure of 17.7 psi) will certainly not like having the ambient pressure reduced from 14.7 to 9 psi. That would be the equivalent of staying at sea level and inflating the tubes to 8 psi (or at least trying to.)
not disputing that
Quote:
I believe he was talking 3000 meters.
in which case the numbers are somewhat exagerated!
Quote:
And, to be fair, tires go to 30000 feet pretty often (though, granted, not car tires...)
good point - I had forgotten about them! There are similar debates in the cycling world about flying bikes around the world...
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Old 04 November 2007, 10:53   #16
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Know inflatable boat makers inflate tubes at the factory to test them at 4.5 PSI for 12 hours for PVC and 6 PSI for Hypalon under shade. The tire example was talking about: 3 thousand meters or about 9 thousand feet on a sunny day. Sun and altitude increses very much the presure of any item containing air.

Imagine a boat inflated to 3.5 PSI at sea level and taken to sunny 5 thousand meters high elevation, will be blown on it's way up. Have seen small inflatable boats blown on high mountains, the owners didn't know about presure issues at high locations when transported from sea level, a real pity

The opposite will be, a boat inflated to 3.5 PSI at a given location altitude, let's say 5 thousnad meters high will have no problem coming down to the coast, tubes will be defleted gradually on it's way down and will look somewhat like big large raisins once at sea level. If the boat is equipped with automatic presure relief valves as in more costly boats, no problem at all.

Anyway in my particular experience the use of a precise presure manometer is a must with normal PVC & Hypalon boats.
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