Naïve question: Side mounting on tropical dive trips

Ok, I know zip, nada, zilch about side mounting other than what appears to be obvious: Independent doubles slung under each arm like stages. Over in Basic Scuba a few folks are re-debating pony bottles and arguing that they make a good travel option since taking manifolded doubles can be arduous.

So... Given appropriate training in their use, could sidemounting a pair of AL80s be a good travel option for situations where more gas and/or redundancy is needed? For example, I just returned from Cozumel. I passed on Punta Sur/The Devil's Throat, a dive that goes to 130' and includes a short cave section. I felt that a single AL80 was cutting things too fine for my personal taste.

Very naïve question, I know, and I am not advocating trying such a thing without specific SM training. Just curious about what people with SM experience think about using them for less technical environments...

I have used back mounted AL 80 independent doubles on trips where manifolded doubles were not available.

Sidemounting AL 80s would work in the same manner but would be, in my opinon, a bit more of a PITA gearing up on the boat.

Are you speaking about diving alone/on your own, or from a boat/group?

Group, with some operator: Most operators won't like it too much to have a diver with doubles, while the rest of the group are single tankers. Why? Because most of the group will end the dive after 45-60 minutes, and they'll have to wait for you an additional hour? Besides, most operators really don't like solo divers, disclaimers signed or not.

If you are diving alone, or going with a group of techies etc, then SM is a good option.

However, you have to consider situations like jumping from a dinghy/zodiac with rough seas and/or current, SM is not an easy task and you may get separated from group (if it exists). Climbing up to the boat may not be easy neither. You may need to modify the tank so that the necks are not only attached by a bungee loop, but some clips to attach them more rigidly (like slinging a pony). After jumping and the dive has started you can disengage the dog clip and let them go on the bungee.

As it is so easy to carry around SM gear, why not take it along with you anyway? The tank cam bands really don't add much, another regulator. What else? Are you using some dedicated rig like nomad/armadillo etc or just modified some BP/Wing?

It is true that most operators get touchy if you dive doubles and dive them to their limits on a recreational charter. I have yet to have issues diving one set of doubles on a two "single" tank boat trip as you are not taking up any more space than the guy with 2 AL 80s. In terms of mild deco, if you are first in and right behind the last recreational diver up the ladder, you don't hold anyone up even with 5-10 minutes of deco, at least in the 80-130ft depth range.

In terms of clipping the tank neck, the stage strap/choker system suggested by Dive Rite works pretty well. You'd just need to unclip the upper snap after you get in the water, place it in the choker and attach the bungee, then reverse the procedure on the safety stop before coming up the ladder. If you run the bungee under the reg rather than use a choker and clip, you can still stage rig the tank and then just use the upper clip getting in and out and either choke it or leave it lose during the dive.

It also depends how low on the tanks the cam bands happen to be. If they are mid way up the tank, they ride pretty well on the towel bars (on a nomad at least) with the bungees holding them vertical. Maybe not secure enough to come up a ladder in rough seas, but secure enough to waddle to the side and fall in. If they are low on the tank, maybe not.

Sidemount is wide open in terms of flexibility. The PITA part for boat diving would be attaching the tanks on deck before getting in - you may either need a bench the right height or some assitance. On a small boat or zodiac, you could put them on in the water and take them off before gettign back on board - just don't drop one. Keeping it clipped to a gear line would be a good idea until you have it clipped on to you.

I can't see how a sidemount rig would be any less arduous than manifolded doubles.

If it's just a run-of-the-mill sightseeing charter then doubles in any config are probably overkill, IMO. (which doesn't sound like it in this case - but, just saying)

i guess they would be easier because you could more easily bring your sm rig & put some cam bands on existing tanks than bring your own manifold & double up existing tanks.

SkimFisher:

I can't see how a sidemount rig would be any less arduous than manifolded doubles.

If it's just a run-of-the-mill sightseeing charter then doubles in any config are probably overkill, IMO. (which doesn't sound like it in this case - but, just saying)

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I was offered a chance to dive Maracaibo on this last trip to Cozumel. It goes from 90' to the drop-off at 140'. Likewise I have been there twice and passed on Punta Sur and its trophy dive "The Devil's Throat" with a swim-through that exits at 130'.

While plenty of divers there are happy to do these dives on a single AL80, I find myself far more conservative than my fellow travelers on the subject of redundancy at depth and gas planning... Of course some would suggest a pony bottle, but once I consider the option of a second tank, I start to ask myself why not sidemount AL80s and save the trouble of carrying a smaller bottle?

Any ways, I am just idly asking questions, I would obtain training before trying an entirely new protocol for diving. I also imagine that on a typical tropical trip I would do most of my diving with a conventional single back mounted tank, although perhaps if I become addicted to SM I could try monkey-diving a single tank as well...

No idea really, just looking into one possible future. For now, I am having a tremendous amount of fun and learning a tremendous amount by simply saying "no" to dives that stretch my comfort level with redundancy and gas planning.

Reg Braithwaite:

Ok, I know zip, nada, zilch about side mounting other than what appears to be obvious: Independent doubles slung under each arm like stages.

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Not exactly. Stage bottles typically hang too low. Sidemount bottles are tucked in next to the body on the same plane.

Jai Bar:

Group, with some operator: Most operators won't like it too much to have a diver with doubles, while the rest of the group are single tankers. Why? Because most of the group will end the dive after 45-60 minutes, and they'll have to wait for you an additional hour? Besides, most operators really don't like solo divers, disclaimers signed or not.

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Just because you're diving 2 tanks doesn't mean you're diving beyond recreational limits. Most boats offer 2 tank trips so why not take your 2 tanks up front and use them together during both dives. Making sure you change your air management to reflect this you can still have the redundancy while abiding by the operator's rules. RB also didn't say anything about solo diving. Sidemounting doesn't equal solo. Besides, most trips like the one RB describes aren't even buddy dives. They are group dives. Everyone splashes and follows the DM around in the water until it's time to surface. There are some buddy groups, but many are just part of the larger group.

Reg Braithwaite:

I was offered a chance to dive Maracaibo on this last trip to Cozumel. It goes from 90' to the drop-off at 140'. Likewise I have been there twice and passed on Punta Sur and its trophy dive "The Devil's Throat" with a swim-through that exits at 130'.

While plenty of divers there are happy to do these dives on a single AL80, I find myself far more conservative than my fellow travelers on the subject of redundancy at depth and gas planning... Of course some would suggest a pony bottle, but once I consider the option of a second tank, I start to ask myself why not sidemount AL80s and save the trouble of carrying a smaller bottle?

Any ways, I am just idly asking questions, I would obtain training before trying an entirely new protocol for diving. I also imagine that on a typical tropical trip I would do most of my diving with a conventional single back mounted tank, although perhaps if I become addicted to SM I could try monkey-diving a single tank as well...

No idea really, just looking into one possible future. For now, I am having a tremendous amount of fun and learning a tremendous amount by simply saying "no" to dives that stretch my comfort level with redundancy and gas planning.

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I agree it's always better to be safe than sorry. For a dive to 130' you don't have much time to dawdle on your NDL or gas reserves. That's an advanced dive and not really the subject of my earlier post. Especially with a swim through at that depth.

There are other single tank options though. I know guys that dive LP95's or 120's (and tanks between those sizes) to those depths and quite successfully. 95's are very popular. Depending on your frame you can go bigger.

SkimFisher:

I agree it's always better to be safe than sorry. For a dive to 130' you don't have much time to dawdle on your NDL or gas reserves. That's an advanced dive and not really the subject of my earlier post. Especially with a swim through at that depth.

There are other single tank options though. I know guys that dive LP95's or 120's (and tanks between those sizes) to those depths and quite successfully. 95's are very popular. Depending on your frame you can go bigger.

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The problem is finding steel tanks at resort locations like Cozumel.