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

[redacted]

A couple uncommon but important exceptions are the Scubapro Mk7 and the Mk 5 with the honker add-on. The honker mechanism will not allow sufficient flow to the primary 2nd stage somewhere around IP or a bit higher. The alternate 2nd will continue to de!iver gas until the tank is empty

 

[scubadada]

...And a moments inattention by the buddy is all it takes (Have you ever had an OOA and tried to breathe from a near empty tank? I have, twice)...

Out of interest, how did you end up nearly OOA, or OOA twice?

 

[BRT]

For what, exactly? How is this related to my post on redundant gas supply?

Because if a 3cf tank is only going to last you 1.3 minutes a 77 cf tank will only give you 33 minutes. Less if you are spending time at depth.

 

[AdivingBel]

I apologize if I came across too strong in my defense of redundancy. It was not my intent to imply divers needed ponies or such but to proviede a safe place to explore options and neceaary info to do so if he/she so chooses.

Absolutely no apology necessary. We all have firmly held beliefs that are usually based on facts derived from our own "survival" experiences . Most times there are interesting stories behind them which is in large part what makes SB informative as well as entertaining.

 

[scubadada]

Because if a 3cf tank is only going to last you 1.3 minutes a 77 cf tank will only give you 33 minutes. Less if you are spending time at depth.

Hi @BRT

I pointed out that I use an RMV of twice my average in my contingency gas calculations, you appear to have missed that. My average RMV over the last 800+ dives is 0.37 cf/min with 95% being between 0.29 and 0.45 cf/min. Using an AL80 and diving 32%, all my dives below an average depth of about 80 feet are NDL limited. Above that depth, my dives are generally gas limited from just under, to considerably over an hour. This works just fine for me under most circumstances.

Good diving, Craig

 

[AdivingBel]

I have had three acquaintances, two online and a third IRL, pass while buddy or group diving.

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

 

[uncfnp]

Out of interest, how did you end up nearly OOA, or OOA twice?

I knew that question was coming. I have actually breathed from an empty tank four times. Two intentionally, two not.

The first was off the pony at the safety stop during my solo course and just for the experience of feeling an empty tank. The other intentional was again at safety stop and off the pony and again just for the experience.

The first time unintentional empty tank I wrote about om my DIY thread amd was an equipment issue. I was trying out my first DIY regulator conversion of a Scubapro 109. I was using it for the first time and as the backup/octo and had no issues. I was solo lobster hunting and had just snagged my last catch and checked my gauge. It was just over 500. So I unrolled my DSMB.and used the 109 to inflate. It freeflowed. Violently. I briefly tried all the usually remedies while also working the bag but knew I was close so also started up. At the safety stop the primary's tank started breathing heavy so I switched to my pony, finished my stop and went up.

The second and most recent was all me and complacency. It was an easy dive, again lobster hunting solo but really hadn't seen anything. So I was just drifing along at about 25 minutes into the dive, I admit I had not checked the SPG at this point since "experiece" told me I should have well over half a tank, when I noticed a change in the work of breathing off the reg. Took another few breaths. Yep. A glance at the SPG confirmed no gas. Switched to pony and went up. I had neither heard nor seen a significant gas loss. Back on the boat I could find no source for the loss and to this day I am not sure what happened to the gas. I did have a bad leak of the DIN o-ring 2 dives later.

 

[wetb4igetinthewater]

... and to this day I am not sure what happened to the gas. I did have a bad leak of the DIN o-ring 2 dives later.

Maybe was champagning on you?

 

[uncfnp]

Maybe was champagning on you?

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

 

[wetb4igetinthewater]

I was referring to the probability of both a catastrophic gas loss and losing even an insta-buddy in a high viz environment on the same dive.

If you choose to not dive as a buddy-pair (due to photography or any other reason), you should absolutely sling a pony. Saying it's foolish to not sling a pony when diving with a buddy especially in the environment specified by the op (warm water, high viz) is your opinion, but it's not borne out by reality (if that's what you're saying).

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