Bose are you there or any other divers

[Fuji Abound]

I had a thought as I head off for some flying in warmer climes and some diving.

I have for years chucked my DV in the case with dive computer without a second thought.

The computer of course has a built in sensitive altimeter - or effectively that is what it is, not designed to register negative depths!

Now I appreciate water is a whole lot more dense that air, but it set me wondering whether the computer can suffer any damage from continued exposure to the reduced air pressure in the hold and whether or not that would hold true for the same flight in an unpressurised aircraft up to FL200.

If not, why not?

[IRRenewal]

If not, why not?

Because water is a whole lot more dens than air.

The computer of course has a built in sensitive altimeter

It doesn't have to be very sensitive, because water is a whole lot more dense than air. Bit of low air pressure is unlikely going to damage a bit of kit designed to withstand many times the sea level pressure.

(non-diver speaking here, just applying a bit of engineering logic)

[mad_jock]

The computers do measure altitude (local ambient pressure) as well it just doesn't tell you its doing it.

The old aladins used to have 3 mountains on the screen telling which band you where in.

The normal was 2 mountains worth in an aircraft and only once i got 3 on a 747 going down to south America. We had a theory that a 12 hour flight would give us extra bottom time but it made no difference.

The most likely way your computer is going to get broken is if its in your checked in baggage and it goes into a unheated hold. It freezes and ice crystals form in the LCD display and breaks that.

[mark147]

damage from continued exposure to the reduced air pressure in the hold

Do any pressurized aircraft have an unpressurized hold? The hold pressure will normally be very close to the cabin pressure. If that were not the case, the aircraft would not be cylindrical.

As mad_jock says, it's more likely to be the temperature that causes a problem. Dive computers are perfectly fine to be taken to altitude.

Mine specifies a 'normal altitude range' of 0-10,000ft AMSL, an operating temperature of 0 to +40 C and a storage temperature of -20 to +50 C. I don't think you're likely to exceed any of those limits for an item in a bag on a commercial airliner for a typical flight duration. If in doubt, take it in hand luggage.

Even above 10,000ft cabin alt (e.g. unpressurized light aircraft) I still wouldn't expect there to be a problem but my Suunto manual has no guidance on that.

Mark

[S-Works]

The answer is no, it will not be a problem. The reduced pressure in the hold at FL200 is equivalent to a descent under water of 3m. Completely negligible. Equally the temperature is a complete non issue. The operating range of these things is usually between -20 to +50c and they are tested way beyond that range. The coldest the hold could theoretically get is -54 but would be surprised that even unheated holds would get much below freezing. As far ice crystals forming and cracking anything, these things are usually tested to around 300atm or just short of 5,000 per square inch. No ice crystal is going to crack anything!!!

The pressure transducer used for dive computers is off a type that is too crude for effective ambient pressure monitoring above the surface on most dive computers. The transducers used on kit like the APD Evolution has more sensitive range as it is used to measure ambient pressure for calibration. But even that will have no effect.

All my kit goes in with my clothes etc and into the hold. So don't worry!

[mad_jock]

My reply about the breaking of LCD screens was based on a few problems we have had with laptops going into the hold and the screens getting done in. And you know what ice does to pipes. You get a big black scar round the area thats burst.

Personally I would keep it on me in hand baggage or jacket pocket. By the time you have bull****ed your weight belt through security along with 3 first stages in your pocket they tend not to bring up a ickle dive computer.

The holds get very cold especially on a long flight. Still every year various animals get frozen to death when they are put in the wrong hold.

But go with bose-x he gets to go to way more exciting places than I do diving.

[Fuji Abound]

Thanks everyone.

[S-Works]

My reply about the breaking of LCD screens was based on a few problems we have had with laptops going into the hold and the screens getting done in. And you know what ice does to pipes. You get a big black scar round the area thats burst.

Understood and very valid, especially if they have been in high humidity areas before hand.

A dive computer has the LCD inside a case designed to withstand several thousand pounds per square inch so is perfectly safe. The same goes with regs etc. There is no reason to hand carry any item of dive kit.

Save the space for buying gadgets in duty free!!!

[mad_jock]

The regs in the pocket were more to do with not paying excess baggage :}

[Fuji Abound]

Thanks again guys. My computer, DV and jacket have always gone in the hold and I have never had any problems I have to say.

Then again the number of times they have been "exposed" to low pressure is relatively few so it is reassuring to know you guys who do it for a living have had no problems over the years. My new dive computer is not exactly the cheapest bit if kit and easily comes out of the octpus so it is good to be reassured it is not worth bothering. Oh well, it is insured as well.

I will keep the notebook with me as I have always done.

[effortless]

My reply about the breaking of LCD screens was based on a few problems we have had with laptops going into the hold and the screens getting done in. And you know what ice does to pipes. You get a big black scar round the area thats burst.

I have lost an early laptop in this way but it was the low presure that did it. The screen simply burst. They were an absolute fortune back then and it was brand spanking new.:{