Equipment My first out of air situation

[scubadada]

Hmm, I DO appreciate the y=mx+b comment...that is my native language. And the problem seems to be mostly m.
If it were mine, I'd first try getting an RMA from Huish before trying to fiddle the electronics:

"All returns, service, warranty, and exchanges require a return merchandise authorization (RMA). To submit a request for an RMA, please send the following information to TAC@huishoutdoors.com:​

​

1. Dealer/customer number (if available)
2. Product information and specifications (i.e. part number, model, size, color, serial number, etc.)
3. Reason for return"

Good luck! Always nice to have a trustworthy spare, instead of something you'd only use on a pony.

That is a good idea, but I don't think Huish will service Aqualung transmitters, serial number prefix FC or FO rather than BM. Of course, nothing to lose by sending the information to Huish by email.

Question Post in thread 'Serial number prefixes on Pelagic Pressure Systems MH8A transmitters'

Mar 11, 2025

I communicated with Huish in January. They still service BM prefix transmitters except for flooding, which includes failure of the OPV. Here are 2 messages from Huish, the second to clarify flooding:

• scubadada

 

[Hatul]

i've not gone over every reply, but the question is what was the tank pressure when you got back on the boat. If the tank still had air it points to a blockage in the air flow, if the tank was empty it means you had a leak or the pressure gauge was bad.

And I agree with others that you should have immediately accepted the divemaster's octo when you found it hard to breathe.

 

[clownfishsydney]

My first thoughts from looking at the screen dump of the dive, a blocked intake on the valve. I have seen this happen before, person thought they were out of air but in fact the valve was blocked by rust particles. Did the OP check air pressure later or did anyone empty the tank and open it?

 

[tiacalypso]

I too would like to see the depth graph.

I don't use AI, but the air consumption graph does not make sense to me: it shows a remarkably constant slope, with ~100 bar used in ~35 min. This is regardless of changes in depth during decent or any changes in diver activity. For folks who do use AI: shouldn't there be greater variation in air consumption rate during decent and during the dive, and not a completely straight slope?

100 bar in say a 12 L tank is 1200 L - so the slope of the graph is 1200L/35 min = 34 L/m at 3 bar/20m. That equates to 11 bar/min on the surface: which is far lower than most experienced divers.

However assuming a more typical breathing rate for an inexperienced diver (say 22 bar/min) would empty a 12l tank in ~35 mins: close to what's seen.

As lizardland points out - I think the issue is with the AI/computer.

Cheers
Rohan.

I‘m an AI diver and my air consumption profiles are pretty linear.

 

[gamon]

I‘m an AI diver and my air consumption profiles are pretty linear.

You gotta watch the terminology or the nature of your reality will be in doubt.

You're a human diver who utilizes Air Integration.