Is there a valid reason for a pony bottle

[dead dog]

Exactly.

And if the plan was to deal with a blown tire on your pickup truck by carrying around a bicycle wheel and using it to drive home at highway speeds, death-in-the-trunk would be a good name plan for that as well. Even though "it's better than nothing".

Geroutofhere!... A bicycle wheel in your trunk. LMAO !

 

[Joneill]

I began my diving career using 72s with J valves. I understand how they work. I was referring to the fact that he ran out of air after getting snagged in the net. An spg would have let him know he was already low on air before swimming under the net. In that incident, a simple spg would have served him more than carrying around an extra tank and reg.

Except, as indicated by another poster, SPG's were not really in use back then... maybe time to stop your anti-pony crusade and let other divers dive how they want? The Op's question has been answered (it's a "yes") by many reasonable, open-minded folks already.

 

[Gareth J]

55 pages - not bad going.

Following the spare wheel analogy

Spare Air = Bicycle Wheel
Pony = Space Saver Wheel (I don't know if you get those in the USA)
Twinset = Spare Wheel

Buddy = Breakdown service

 

[doctormike]

55 pages - not bad going.

Following the spare wheel analogy

Spare Air = Bicycle Wheel
Pony = Space Saver Wheel (I don't know if you get those in the USA)
Twinset = Spare Wheel

Buddy = Breakdown service

Good analogy!

And since sometimes the breakdown service doesn't show up, better to be able to take care of things yourself...

 

[Storker]

since sometimes the breakdown service doesn't show up, better to be able to take care of things yourself...

To continue the analogy: I have AAA premium and excellent cell phone coverage

 

[KenGordon]

By the way I was wondering: when you dive manifold doubles, if you go on a trip and do two dives, then you have to keep your tanks for the second dive, isn’t it ? It’s not like you can swap tanks or refill when on a boat ?

So you are getting the same quantity of air than someone who swaps a single cylinder during the interval, isn’t it ? (You still have redundancy if you can use the manifold though l)

For UK dives either you can get a fill on the boat or not. If you can get a fill you are fine. If not you either plan to do the second dive on whatever remains or top up with a whip. If the dives are single tank range then you are probably doing the second dive with more than half the twinset left so are ahead of having used two singles. If the second dive really needs more than that you end up taking a full 15 or a 300 12 and using a whip to top up the twinset.

If the first dive was sufficiently full on to mean this will not work then is probably not going to be a second dive, the exception being liveaboards in places like Scapa, but there you get your twinset filled on the boat.

Twinset logistics can get hard when you want to dive consecutive days and need awkward to obtain mixes. You have to have a plan to be able to get a fill after the boat gets back.

 

[MaxBottomtime]

Except, as indicated by another poster, SPG's were not really in use back then... maybe time to stop your anti-pony crusade and let other divers dive how they want? The Op's question has been answered (it's a "yes") by many reasonable, open-minded folks already.

Since you have difficulty with reading what I said, I'll repeat it.
A situation like that could now be avoided by having and monitoring an spg.
Note that I said now, not back then.

 

[tursiops]

I began my diving career using 72s with J valves. I understand how they work. I was referring to the fact that he ran out of air after getting snagged in the net. An spg would have let him know he was already low on air before swimming under the net. In that incident, a simple spg would have served him more than carrying around an extra tank and reg.

"I untangled my valve from the net by taking off my tanks off and swam out of the wreck with my tanks under my arm handed off my camera and put back on my tanks, then I was out of air."

That doesn't sound like low on air to me. Either way, an spg would have stopped him from getting into the situation in the first place. Like many of the arguments for ponies in this thread, the out of air could have been avoided by simply knowing how much air you have.

Since you have difficulty with reading what I said, I'll repeat it.
A situation like that could now be avoided by having and monitoring an spg.
Note that I said now, not back then.

Really? Read your own posts.

 

[Joneill]

Since you have difficulty with reading what I said, I'll repeat it.
A situation like that could now be avoided by having and monitoring an spg.
Note that I said now, not back then.

Really? I can't read??? Lol! Actually, my reading comprehension is just fine - it's yours that seems to be questionable... I was responding to what you had posted which was EXACTLY what I linked via quote. Here is is again:

I was referring to the fact that he ran out of air after getting snagged in the net. An spg would have let him know he was already low on air before swimming under the net. In that incident, a simple spg would have served him more than carrying around an extra tank and reg.

You were speaking in the past tense and made no reference to "now". So, maybe, leave your sarcasm out next time?

 

[CWK]

I shared my dive from October earlier in the thread. Perhaps it may be worthwhile to say a few more words about it.

The boat I was on told us to dive to 50 bar then ascend and do a safety stop. On that day, I had 65 bar when I decided to ascend to do my safety stop. This is quite unusual for me to leave the party early. At that time, my computer showed a NDL of 4 mins. If I had stayed another 4 minutes at 21m and run my gas down to 50 bar things could have gotten worse as the current had been increasing throughout the dive. If I had stayed another 4 minutes, the washing machine could have strengthened driven me down to 40m. Consider another line on my log. The red line in the attached file.

The red line shows that I incurred a 1 min deco obligation at 3m when the washing machine drove me down to 32 m. I could very easily have been OOA with a more significant deco obligation had I chosen to stay those extra 4 mins.

I quite like diving with my pony.