Question Redundant gas when traveling?

[steinbil]

I almost exclusively dive back mounted doubles here in Norway, and when I went to Dahab last year I was able to rent doubles, but many places in the world that's going to be tricky. I would prefer having redundant gas and regs in the 60-100ft range, especially when diving with random buddies and groups I can't necessarily rely on in case of a failure.

The solutions I see talked about most here on SB are pony bottles and sidemount. Why not just dive with an extra bottle as a stage?

Pony bottle
+ reserve gas (for one diver)
+ smaller/lighter
+ compatible with recreational gear
- need to buy a pony
- need to travel with tank
- possibly higher risk of failure if its not used/tested on every dive

Sidemount
+ full redundancy
+ no need to travel with tank
+ balance in the water
+/- one less second stage
- PITA on boats
- need 2 bottles for every dive
- need to get right-handed valve bottles (how?)
- need comprehensive training
- need extra gear (unless that's all you dive)

Single tank + stage
+ full redundancy with two regs on reserve gas
+ compatible with recreational gear
+ only need 1 extra tank for a whole trip
+ no travel with tank, just a stage rigging kit
+ no other purchases/gear necessary
- slightly more to handle on boat than pony (less than sidemount)


Am I missing anything? Why are pony bottles and sidemount so popular? Is it really that much more uncomfortable diving with an AL80 stage than a pony, that you want to travel with a tank? Are there any other drawbacks to diving with a stage that I haven't thought about?

 

[tursiops]

The second cylinder may not be available....for example on a crowded or small boat, or if shore-diving at a place that is stingy on giving out tanks.
On many dives, you are limited in bottom time...so a second cylinder is unnecessary except for redundancy, and much bigger than needed for use as a back-up gas source.

 

[tbone1004]

@steinbil fundamentally you are talking about using that bottle as a pony, just a slung pony instead of a mounted one. If you feel that you really must have that then I would recommend putting a loop bungee on the left so you can pull the neck of the bottle up for streamlining and keeping it from flopping around. This has become fairly common in the backmount rebreather crowd with sidemounted bailout.

You do have to figure out if you're going to use it as a stage or as part of your backmount gas and how you contend with gas planning. If you're going to do that then I would probably just use the stage bottle for the entire dive and keep the backmount bottle full but that is up to you to sort out

 

[grantmac]

Have you ever dove sidemount? Because most of your negatives don't actually exist except needing gear and training.

 

[iointerrupt]

The short answer is, most places that see vacation divers everyday, will not trust you with a second AL80. They are doing 45 minute "look at the pretty fish" dives. They don't want to wait around for 30 minutes while you gear up, and they really don't want you suddenly doing a 2 hour decompression dive.

Show up with an AL19 or AL30, and they'll still be suspicious, but not enough to actually say no to it.

Now if you are doing unguided dives, you can do whatever you like, but that's one of the big reasons for the travel pony. Just less of a fight.

 

[steinbil]

You do have to figure out if you're going to use it as a stage or as part of your backmount gas and how you contend with gas planning. If you're going to do that then I would probably just use the stage bottle for the entire dive and keep the backmount bottle full but that is up to you to sort out

Yes, that would be the strategy. I would breathe the primary reg on the back mounted bottle to splash. Check the necklace is breathing ok. Then switch to the stage for the entire dive, keeping the back gas for emergencies and gas sharing with other divers. I guess the drawback is that you're switching out the stage every dive, meaning you have to re-rig it every time, unless you have a couple to rotate between and can get filled. I don't know how feasible that would be with different operators.

 

[steinbil]

Have you ever dove sidemount? Because most of your negatives don't actually exist except needing gear and training.

No, I have not. So it is purely based on what I've heard from other divers and here on SB.

 

[steinbil]

The short answer is, most places that see vacation divers everyday, will not trust you with a second AL80. They are doing 45 minute "look at the pretty fish" dives. They don't want to wait around for 30 minutes while you gear up, and they really don't want you suddenly doing a 2 hour decompression dive.

Show up with an AL19 or AL30, and they'll still be suspicious, but not enough to actually say no to it.

I didn't consider this angle. Obviously if the operator does not allow it, that would be a problem. Is this common?

 

[tbone1004]

Yes, that would be the strategy. I would breathe the primary reg on the back mounted bottle to splash. Check the necklace is breathing ok. Then switch to the stage for the entire dive, keeping the back gas for emergencies and gas sharing with other divers. I guess the drawback is that you're switching out the stage every dive, meaning you have to re-rig it every time, unless you have a couple to rotate between and can get filled. I don't know how feasible that would be with different operators.

there are stage kits that use cam bands that are quick to swap, more sidemount kits than stage. You would not want to do that with standard DIR rigging, the operators would hate you. You would use something like this where you have a single cam band and it slips off easily

Travel Stage Strap - Dive Rite

Make rigging easy on yourself. Quickly set up stage, deco, or sidemount bottles without tools using our Travel Stage Straps. Two hose retainers (one deluxe and one standard) and the 1.5-inch low profile cam strap are captured in the stage strap, keeping the entire set up connected as one...

www.diverite.com

 

[grantmac]

No, I have not. So it is purely based on what I've heard from other divers and here on SB.

I've spent the last 4 months exclusively using sidemount for redundant travel use, including diving off boats. Everything from 3AA steels in Japan to AL80s in Bali with only minor weight adjustment. 3-4 dives a day swapping tanks with cam bands.
I find none of the issues people seem to struggle with.