Gas Management With Sidemount

[wetb4igetinthewater]

Pairing often sucks when the components age and batteries are replaced late.

I can see an issue with batteries but not with components aging when we are talking about electronics. Please explain.

 

[Razorista]

I can see an issue with batteries but not with components aging when we are talking about electronics. Please explain.

They get bumped and rattled around a lot.

Electronics also do not like pressure changes, glues age, rubber looses flexibility, plastic gets brittle, circuit boards as well, etc...
Most importantly there are huge temperature gaps between inside and outside, first stage connected side and the end sticking into the water, so you get condensation and corrode your electronics slowly.

Personally I do not trust electronics in the water at all and especially do not want any of that close to my air supply, but that's paranoid, I admit.
Especially at the surface I do not want to increase the chance of batteries close to highly concentrated oxygen or extreme drops of temperature on the frequent surface-freeflows when a tank is dropped at a bad angle.

 

[mddolson]

There's a nice Sidemount article in X-ray magazine in #56 that includes tank/reg switches.

 

[Jack Hammer]

Might want y

Jack Hammer ; he posted his cave fill is 3600 so his thirds are 1200

Re read the post, even after removing the typo ("each tank"), it doesn't add up. ☺

 

[Dhboner]

There's a nice Sidemount article in X-ray magazine in #56 that includes tank/reg switches.

I was taught by Steve Lewis (the author of that article) and I can attest that his methodology for gas management/regulator switching works flawlessly and becomes intuitive in no time.

 

[wetb4igetinthewater]

There's a nice Sidemount article in X-ray magazine in #56 that includes tank/reg switches.

Thanks! For those interested, here is the link to download: X-Ray Mag #56 | X-Ray Mag or http://www.xray-mag.com/pdfs/xray56/X-Ray56_iBook_locked.pdf. The diagram makes it super simple, and basically covers what I was thinking for the start. Breathing from one tank after the turnaround makes complete sense, as if you have a failure from the tank from which you are breathing, you have in reserve enough gas to get you back.

 

[kensuf]

Breathing from one tank after the turnaround makes complete sense, as if you have a failure from the tank from which you are breathing, you have in reserve enough gas to get you back.

Gas has weight. As you use gas, your tanks weigh less. The shift can be dramatic -- an AL80 weights 6.4lbs more when it's full than when it's empty. You might be putting yourself out of trim by doing this.

 

[DA Aquamaster]

The most foolproof and effective way is to switch as often as you get the chance.
Every time you have a hand free for that, just switch without checking pressure or time.

With that method you just look at your spgs occasionally to check for stupidity, but have the tanks more or less equalized all the time without checking constantly.../

I'm never going to agree with that. It's not a system, and it's not plan, it's just switching every time you have a hand free, and if you get very task loaded, it might not happen.

Also the advantage of starting on the left, switching to the right and then switching back to the left, you're on the right tank at the half of the dive at greatest penetration.

With a 5' hose on the right tank going to my mouth, and a 5' hose on the left tank going to a bungee necklace around my neck an out of gas diver can just take the reg out of my mouth. If I'm on the left tank the OOG diver can do the same thing, it just slips out of the bungee and I pull the other one off my right chest D-ring, but it's slightly cleaner the other way.

 

[Razorista]

...It's not a system, and it's not plan, it's just switching every time you have a hand free, and if you get very task loaded, it might not happen....

Again, think of it the other way round!

I had trained for exact reg switches and was using a 10 or 20 bar rhythm when I realized the way I was doing it was totally 'wrong'.
It was just an unnecessary and avoidable (and thereby dangerous) taskload.

When I missed a regulator switch because of something unforeseen happening the whole dive plan was affected, getting back into the rhythm could take several switches.
I caught myself several times trying to make a gas switch in inopportune situations or stopped a recording early to make the switch.

Removing the necessity of gas switches and replacing it with a more natural system reduces taskload and increases control.

I rarely leave the water with unequal pressure since I started doing it this way, even when entering the water with used tanks with pressure unequal from the beginning of the dive.
When reaching the last third I always have the tanks equalized and I rarely look at the spgs before leaving the water.

 

[wetb4igetinthewater]

They get bumped and rattled around a lot.

Electronics also do not like pressure changes, glues age, rubber looses flexibility, plastic gets brittle, circuit boards as well, etc...
Most importantly there are huge temperature gaps between inside and outside, first stage connected side and the end sticking into the water, so you get condensation and corrode your electronics slowly.

Personally I do not trust electronics in the water at all and especially do not want any of that close to my air supply, but that's paranoid, I admit.
Especially at the surface I do not want to increase the chance of batteries close to highly concentrated oxygen or extreme drops of temperature on the frequent surface-freeflows when a tank is dropped at a bad angle.

Vibration is very bad for electronics, which is why I am pretty careful with my gear. BTW, my undergrad was EE, though I'll admit while I worked for Intel for a number of years, I mostly developed software.

While glues age, plastics becoming brittle, and rubber loses flexibility, I don't see that as relevant as long as one maintains their gear. I don't see that as being a failure point in normal cases. With regards to circuit boards, there are computers that are still running DOS 24 hours a day in some places. I don't think my dive computer, now a year old is at risk of stopping to work.

If the manufacturing process of the dive computers is properly done, there is a vacuum inside, so that there is no moisture in the air, and therefore no condensation. Water doesn't cause corrosion btw, but salt does.

I don't believe there is a fire risk in the scenario you described. But thank you for your input. But without a background in electronics, I don't wish to debate this topic.