Why give primary instead of alternate regulator?

[Storker]

@KWS you made me feel better abt loosing my new scubapro reg plug! Thinking thru my method on this thread now makes me feel the Alternate reg Should be unplugged in water.

Uh, what? Plugged alternate?

How would that go if someone were in a hurry and needed gas from you?

 

[wetb4igetinthewater]

Uh, what? Plugged alternate?

How would that go if someone were in a hurry and needed gas from you?

I think he meant uncovered. There are two octo holders I can think off that can plug an octo, but I am not sure about if they make a water tight seal.

 

[BlueTrin]

Back in the day when we did buddy breathing because we only carried one reg there were a number of reg failures (free flows). Theses were caused by the reg suddenly being flooded.

This still applies now. Take a reg out of someone’s mouth and there is an increased likelihood it will free flow. Take a secondary that is already flooded, there is less likelihood it will free flow when the OOG diver needs it.

Is it the second stage or the first stage the most likely to free flow ?

 

[Khrissi]

Uh, what? Plugged alternate?

How would that go if someone were in a hurry and needed gas from you?

Exactly @Storker So am glad it went missing and i did not use the idea. K

 

[Edward3c]

Is it the second stage or the first stage the most likely to free flow ?

Only the 2nd stage is affected by being immersed in water. How often does an octopus go into free flow when entering the water. I see it quite often when shore diving, it isn’t a reaction to jumping off a boat, but from water entering the reg. The same can happen when a reg is removed from a diver’s mouth underwater.

 

[KenGordon]

You lot should try this for a laugh. Set your bungeed short hose to breath to the max. Induce a freeflow and see how your shutdown drill goes. The fun bit is you have a free flowing reg right in your face so seeing and acting is all a lot harder.

 

[doctormike]

Only the 2nd stage is affected by being immersed in water. How often does an octopus go into free flow when entering the water. I see it quite often when shore diving, it isn’t a reaction to jumping off a boat, but from water entering the reg. The same can happen when a reg is removed from a diver’s mouth underwater.

So this is a big problem for sidemount divers? It seems so popular lately, but I never heard that...

 

[Edward3c]

So this is a big problem for sidemount divers? It seems so popular lately, but I never heard that...

Most divers when deliberately removing regs turn the mouth piece down to minimise the risk of free flow. Completely different to a reg taken from another diver.

I’m not saying it will happen each and every time regs are grabbed, but the risk is increased.

 

[doctormike]

Most divers when deliberately removing regs turn the mouth piece down to minimise the risk of free flow. Completely different to a reg taken from another diver.

I’m not saying it will happen each and every time regs are grabbed, but the risk is increased.

Will take your word for it, just surprised to hear that it's a significant risk, given the fact that PD is pretty standard stuff for technical training.

I'm not saying that you can't make a case for SD, but I would think that if this was a major issue, the agencies would have addressed it. Ever time I learned PD in tech training, it was grab the primary on the long hose, duck your head, and plug in the OOG diver.

 

[Oitzu]

The free flow while taking the reg out of the mouth isn't caused be the sudden rush of water but by the diver still slightly sucking on the reg and therefore pulling the diaphragm slightly in or a sudden movement of the second stage forward, that pushes the diaphragm in. The venturi effect keeps the freeflow running.
When you turn the mouthpiece down the reg fills with air and pushes the diaphragm outward again.

The freeflow while jumping of the boat is most often induced by the diaphragm side of the reg hitting the surface of the water.