Mild warning

[InTheDrink]

So today I was diving in Gozo. For whatever reason there was confusion and they only had DIN tanks (superior, I bought mine with an A clamp in 2008 when I didn’t know better).

Dived with their rental regs (plus my DIN pony).
After the dive back to the shop and tried 3 A clamp inserts. Gas was still going down probably 50 bar a minute. Scratched head.

Listened a little closer and my HP hose right by the first stage was split and just waiting to do a full on burst.

I would have been fine as had redundancy and would have got someone to turn of my main first stage.

But it was a salient reminder of complacency. I would have caught the issue before jumping in cos of the gas bleed.

But truth be told I haven’t really checked my hoses for a long while.

So it was a non event but it’s worth a mention to check your hoses once in a while and obviously check you SPG to make sure it’s not bleeding gas. Because I thought it was the A clamp O-ring I fixated on that. Thankfully the bleed was significant enough for my to check the hoses.

So just a little word of caution. Keep an eye on your hoses, look for bulges, and replace maybe a little sooner than I did. It’s not really a failure mode (particularly HP) that I check out but it’s a quick check that might avoid a little shock underwater.

Another good reason why I always dive redundant gas.

Thanks and hopefully will help someone at some point.

John.

 

[clownfishsydney]

HP hoses normally have two layers. If the inside one splits, the outside one will stop you having a huge loss of air. The outside one also has thousands of tiny holes so that if the inside one splits, you will know as you will hear or see air escaping. This escaping air is not so bad to cause you a problem. This will then make sure you replace the hose.

 

[InTheDrink]

HP hoses normally have two layers. If the inside one splits, the outside one will stop you having a huge loss of air. The outside one also has thousands of tiny holes so that if the inside one splits, you will know as you will hear or see air escaping. This escaping air is not so bad to cause you a problem. This will then make sure you replace the hose.

Agree. I would have noticed my gas empty before I’d even got in the water. The outside one was bulging and perhaps a small slit just where it meets the metal sheath so imagine damage done in transit.

Still, I’ll check my hoses a little more frequently now. Blowing an LP house is also excitement I can live without.

And even the HP would have bled the full tank in 5 mins if it has split underwater.

 

[Bob DBF]

Life Ending Seconds • ADVANCED DIVER MAGAZINE • By Curt Bowen

A full 80 cubic foot cylinder will empty in 72 seconds if the burst disk fails on the surface and 74 seconds if it fails at 99 or 232 feet. It will empty in 22 minutes if a high pressure hose ruptures, regardless of depth. If a low pressure hose ruptures, you've got 83 seconds on the surface, 81 seconds at 99 feet and 82 seconds at 232 feet. If your regulator free flows, you've got 255 seconds on the surface, 155 seconds at 99 feet and 91 seconds at 232 feet.

The rates are for a fully open hose, failures, in my experience, are usually a leak rather than a burst. The only burst hose I had was on a borrowed upstream reg without a pressure relief back in the '70's.