Looking to start diving in sidemount or doubles. Which one first?

[broncobowsher]

BB...

All good points...but nothing beats...taking the time trying...before spending the money buying...

As far as cylinder collecting...at some point...annual service costs/actual use/practicality far out-strip bragging rights and ''perceived need''...

W.M...

Since the OP wants to do both, I'm not down the path of which is best in a pool test dive. It's which one to start with. If he is really going to own both setups, I think sidemount is easier to get into with what he is starting with.

As far as the cylinder collecting, Every time I thought I was going to get rid of one because I got something different I found I still had a need for the one I was going to get rid of. Twice I thought I was going to sell off my AL80s, only to keep them. Both have trimix in them right now. Steel 100s, don't dive them, but they are a good way to get clean high pressure air home from the dive shop. AL40s, OK I may have an extra one that I don't use but I bought the last two as a good deal on a pair. I have one extra cylinder. My last 3-day road trip dive weekend I had 10 cylinders in the truck with me, used everything I brought. Yes the annual service is a pain, but it is what is needed. Now if I owned 2 more 3L bottles I could have left 3 big bottles and the booster at home. So really I need more. What could I really get rid of? One of the AL40s and one HP100 are not completely needed. But the HP100s are twins, consecutive numbers. Been thinking that they would be good for doubles. So one extra AL40.

A cylinder is usually one of the last things someone buys when getting dive gear. It is also one of the items they can never get rid of and just keep getting more. Starts off with wanting to make more dives in a day/weekend before going back to the dive shop. Turns into collecting special cylinders for special needs. The only "perceived need" in owning all the cylinders I own is the need to dive. I could just go back to renting an AL80 from the dive shop and dive a single tank setup. That would get rid of all my annual service costs. But it will also limit my diving.

 

[stretchthepenn]

I was facing much the same quandary as you, @SWiggs. My choice was to go SM first and then do BM doubles for my tec training. I'd suggest the same for you. Here's my thinking:

You want to dive wet for the next year. Diving wet with SM steels is awesome; you might not need to carry any additional weights, and if the buoyancy situation gets amazingly craptacular, you ditch a tank and all's well.

You've budgeted six months for practicing the system you choose. That's just about perfect for accumulating 50 dives, which is the number of SM dives that my instructor recommended I get in before starting any further training. (He was spot-on with that suggestion, BTW.)

You're in/near cave country, where there aren't a lot of wrecks. SM is superior for caves, period, so if you ever get into training for overhead environments, the time invested in learning SM will pay off quickly.

You want to move on into tec diving, which will require you to carry stage bottles and switch regs on the fly. SM is excellent preparation for both those skills. For one, SM basically is diving two cleanly-stored stage bottles; carrying one during your tec class will feel natural, and you'll reduce task-loading during deco. For two, swapping regs between main backgas and a stage bottle is almost identical to swapping regs during an SM dive; SM experience makes it a breeze.

You currently own two tanks. If you go BM doubles first, you're either looking at buying another tank (preferably steel) for all your non-BM doubles diving and then another matching tank when you go SM, or you're gonna waste a lot of time and energy (and maybe air fills) setting up and breaking down your doubles.

You can take your tec course in BM doubles and apply the lessons to SM much more easily than vice versa. I learned SM first, switched to BM doubles for my Tec40 course, and have done tec dives in both SM and BM doubles. However, I'd definitely not want to try a tec dive in SM without having a lot of SM experience.

Whatever road you go by, though, have fun.

 

[ajtoady]

What I have not seen addressed here is, are you capable of reaching back for valve drills? Could influence your move into tech or fundies. I am not, due to shoulder surgery and a life of abuse to the shoulders. As for which to start with, does it really matter? I enjoy both, whatever the "mission" calls for. With back mount twins I use the independent setup. Sidemount, basically the same construct, independent again. Gives me the redundancy I like for solo dives. As for boat entry and exits in side mount, just like everything else, it's a learning curve. Which ever you decide, it's all about having fun and enjoying the sport.

 

[LandonL]

Extended range can easily be accomplished with larger single cylinders...HP steel 100's/117's/120's/133's/149's...

Extended range on a single cylinder is a poor idea. You should either be in BM or SM, never a single tank setup.

 

[wetb4igetinthewater]

Extended range on a single cylinder is a poor idea. You should either be in BM or SM, never a single tank setup.

Can I get an “Amen!”?

 

[W W Meixner]

Extended range on a single cylinder is a poor idea. You should either be in BM or SM, never a single tank setup.

L...

Extended range was intended to mean...a little more bottom time than you'd get from a small cylinder...like getting more bottom time from a HP steel 100...than you'd get from a 3AL 80...

I did suggest that he make arrangements with a qualified instructor and try both systems before he spent money on something for nothing...the OP did not clarify his purpose...or need...only a desire...

''Extended range''...doesn't necessarily mean ''tec''...unless your name is ''Mares''...

W...

 

[wetb4igetinthewater]

L...

Extended range was intended to mean...a little more bottom time than you'd get from a small cylinder...like getting more bottom time from a HP steel 100...than you'd get from a 3AL 80...

There was never any indication from the OP as to why he wanted to venture into doubles configuration...the suggestion of a larger single cylinder may have more then fulfilled his needs...

Extended range...doesn't necessarily mean ''tec''...unless your name is ''Mares''...

W...

If you consider minimum gas requirements, that’s just a bounce.

 

[W W Meixner]

If you consider minimum gas requirements, that’s just a bounce.

W...

Or having enough gas to fully circumnavigate the full circumference of a shallow quarry as opposed to only being able to get part of the way around...

No ''tec'' or doubles required...just volume...''so you can extend your range''...

We had just that...until the property was sold...max depth 30 ft...if you had the volume...you could spent two + hours in the water on a single dive...lots of perimeter wall...not tec...buts lots of fun...multiple car wrecks...boats...small Cessna...

W

 

[abnfrog]

Christ all mighty......................... extended range is deeper diving on air ................ if you took a f&*cking course past advanced open water you would know that .............its not time underwater. ...................dunning kruger all right Extended Range Diver - SDI | TDI | ERDI | PFI

 

[Gareth J]

I struggle with the idea of switching to side mount.

The are some advantages, including the valves being easily accessible. The ability to kit up in the water, and potentially swap cylinders in water. Being able to move the individual cylinders to the waters edge, and kit up in water. Similarly, the ability to dekit prior to leaving the water. This could be advantageous if moving the weight of a twinset is an issue. For those with mobility issues there are also advantages. Being able to dekit in water to pass through restrictions could also be advantageous. For holiday diving, it is probably more flexible, it's easier to configure any single cylinder for side mount use. A solution I have used in the past on holiday, a single back mounted cylinder and a side mount when redundancy has been beneficial, but no twinsets available.

The big struggle I have is that if you have an issue with cylinder/valve on one cylinder, you can't scavenge the gas from it like you can with a manifolded twinset. The original reason I ditched individual twins, was a regulator failure which resulted in a half full cylinder that I was unable to use. That and the issues that followed mean't I basically in the position that I could run out of gas even though I still had 130bar of gas in the unusable cylinder. Luckily, I was very aware of the cascading problems, and so was my buddy, once I got shallow enough I was able to switch to the travel mix.
Even if you are diving a twinset with the isolation valve closed, as I have, on borrowed rigs. I know I can always shut a cylinder and open the isolator to scavenge the gas if push comes to shove.

Gareth