Spare air/pony bottle---should I get one?

[wetb4igetinthewater]

Possible but enough for that kind of loss I should have heard.

I don't think you'd hear it. I had a champagning SPG that did result in the loss of a couple hundred psi off double HP100's. just replaced the tiny o-rings and lubed and all good.

 

[uncfnp]

After re-reading your post, I didn't mean to imply your losses were somehow "entertaining." I'm sorry for your loss.

I didn't take it that way at all and only the one had I met IRL. But they were all unexpected and wake up calls, each in their own way. The diver I knew I met on a dive boat in Florida and both Eric and I were concerned at her lack of skill despite having nearly reached "master diver" level. That week we tried to help her as we could and even introduced her to one of our favorite instructors and encouraged her to take a PPB course from him. We learned on a later trip that she had died just a few months earlier under similar circumstances as the recent tragedy in Cozumel, last seen alive after being assisted to her safety stop.

 

[scubadada]

Hi @uncfnp

Lowest tank pressure I've had was in the 200's, no noticeable change in breathing. Most of my diving is drift with free access to the surface, I frequently surface with 3 and 400s. I will have to try breathing a cylinder to empty sometime so that I know what it feels like, that sounds like a good idea.

Best, Craig

 

[uncfnp]

Hi @uncfnp

Lowest tank pressure I've had was in the 200's, no noticeable change in breathing. Most of my diving is drift with free access to the surface, I frequently surface with 3 and 400s. I will have to try breathing a cylinder to empty sometime so that I know what it feels like, that sounds like a good idea.

Best, Craig

I encourage anyone that can do this safely to try it. Many say there is no difference with modern regulators but I definitely felt it changing.

 

[RainPilot]

I do this with my students in the pool. There is definitely a noticeable change in work of breathing as the tank empties.

 

[redacted]

I used an Al 63 to breath each of my main regs down to an empty tank in my pool so I know how each performs. Did same with my pony regs on an Al 13.

 

[KeithG]

I am talking about photographers. Non photographers have no such distractions that can consume so much of their attention.

My experience with other photographers is that it is often that they can easily drift apart when both are engrossed in their respective subjects. That is very much a reality. However, some divers, like nwgratefuldiver, have exceptional buddy skills and in between shots checks for his buddy. But Bob is not typical. He certainly is a role model for awareness and buddy skills

Ownership of a camera is not an excuse for negligent buddy diving skills. You are either diving as a buddy pair or you are not.

I am not sure there is much use in trying to formulate rules for "bad buddy diving".

If you are not buddy diving, then you are solo diving. Different situation with well understood best practices.

 

[uncfnp]

P.S.: Years back I asked about how hard it is to get the valve off, then back on properly tight, on a pony bottle since you've gotta have it off for air travel. Don't recall exactly what I was told, but I'm under the impression it's more involved that my Spare Air 3, which is surprisingly easy. Anybody care to comment?

The first time off will depend on how aggressively it was installed. We needed a wrench. When we reach our destination we just hand tightened. The tank pressure and o-ring do the rest. And we fill ourselves from a rental tank so no issues with vip's or inspections. Then when ready to fly back its usually just a tap on the handle to loosen then remove. We use a tank plug that our LDS gave us to plug the tank during travel.

 

[BRT]

Hi @uncfnp

Lowest tank pressure I've had was in the 200's, no noticeable change in breathing. Most of my diving is drift with free access to the surface, I frequently surface with 3 and 400s. I will have to try breathing a cylinder to empty sometime so that I know what it feels like, that sounds like a good idea.

Best, Craig

Turn your tank off and breath it down.

 

[RainPilot]

Turn your tank off and breath it down.

The problem with that is that it's quite abrupt compared to a emptying tank, very different sensation. If you play with closing the valve a little at a time you get to a sweet spot where it matches, the spg drops to just above zero at the end of each breath.