Sidemounts versus Twin Tanks On The Back

[rx7diver]

Another member here whose name I cannot remember mentioned a number of times that he took stage rigging for an AL80 on overseas trips. Very easy to pack and getting an extra AL80 was rarely an issue.

I've never slung an Al 80. I suspect I wouldn't prefer to sling an Al 80 for BO if I am diving a single BM Al 80 on a recreational dive. The old Al 30 (smaller OD than an Al 40) or an Al 19 would almost certainly be better for this, probably. The Al 19 is almost certainly easier to travel with, and dive.

rx7diver

 

[Wibble]

The point is that "resort" dive operations have loads of ali80 cylinders. Bring the stage rigging -- even a cam band variant -- and you can dive with a bottom stage cylinder, just as if it were a normal decompression cylinder.

It's not hard. In fact it's incredibly simple.

The main problem is that you've got DiveMASTER guides who will be shepherding the group and woe betide anyone who thinks they can do more than the mandated 45 minutes...

 

[rhwestfall]

No one dives manifolded unisolated twins with a single regulator anymore.

 

[billgraham]

Never went back to what?

Backmounted doubles.

 

[johnnywulff]

Backmounted doubles.

Hi me either, sell all backmount stuff

 

[exodusmaximus]

Backmount is better off a boat. Sidemount works quite well at my local dive sites where entry is easy. In addition, if you have any physical issues with doubles - leg/knees/back that can’t take the weight of doubles or shoulder issues that make valve drills difficult or impossible - sidemount works quite well. That’s why I took up SM (bad knees/sciatica). Can either carry tanks one at a time or roll them around in a cart (I do the latter).

I'm struggling with the same. The idea of having 2 tanks right there is just AWESOME!!! Twins on the back are heavy. Just can't decide (I'll read trough this thread)

 

[exodusmaximus]

ha ha ah ha ha

View attachment 782035

two reg sets, who needs all that extra crap

Hmmm... idk, redundancy?

 

[Cthippo]

Hmmm... idk, redundancy?

So, let me explore this a bit, because I have had doubts about this concept since I started diving.

BM doubles with an isolator provides redundancy against equipment failure (reg, valve or O-ring), but not an OOG situation because you can consume all your air without having to take a physical action (pull a reserve, switch regs, etc).

A larger single tank plus a pony, or diving sidemount, provides redundancy against both equipment failure and (mostly) against human error. It is more redundant because you have to take some physical action to use up all your air. It's possible that someone could take that action without recognizing its implications, but that seems unlikely.

So, ir seems to me that Non-isolated doubles with an adequate pony would be better than isolatable doubles without.

Fundamentally, it comes down to what is most likely to fail, the hardware or the squishy part between the ears? Once someone answers that question, then they can start mitigating the hazard they feel is more significant.

 

[Wibble]

I'm struggling with the same. The idea of having 2 tanks right there is just AWESOME!!! Twins on the back are heavy. Just can't decide (I'll read trough this thread)

Sidemount is far more flexible than backmount. This flexibility comes at a small cost of faffing around to clip the kit together. Practice solves that.

One benefit of sidemount is being able to split the cylinders from the rig, both underwater or for carrying to the site. It’s so much easier to throw a single cylinder over your shoulder and carry it up/down the beach or over the mountain.

Other benefits of sidemount are the comfort and trim from not having a massive weight on your back. Access to the cylinder valves is so much easier, similarly seeing all hoses and regulators rather than groping around behind your head.

If diving alone, sidemount is far superior to backmount.

 

[BoltSnap]

Access to the cylinder valves is so much easier, similarly seeing all hoses and regulators rather than groping around behind your head.

benefit of sidemount is being able to split the cylinders from the rig, both underwater or for carrying to the site. It’s so much easier to throw a single cylinder over your shoulder and carry it up/down the beach or over the mountain.

If diving alone, sidemount is far superior to backmount.

THIS ^^^^^^^^^^

(First time I agree with @Wibble 100%)