Sidemount - steel 10s

[Mikael]

Short question how do people find sidemounting steel 10s?
Comfort, ease of trimming out, usable gas?

Background:

I am about 180cm tall (5'11''). I have an Xdeep harness. I use loop bungees and waist d ring. I rig the cylinder and harness so torque between the neck and lower connection point keeps it tidy to the side of my body.

I like to shore dive, sometimes involving clambering down to access the water's edge and have experimented with hauling euro 12s which has been a mixed bag over wearing a comparable twinset and walking down in terms of effort and ease.


For shore diving I don't need a ton of gas and so the idea of going down a size is appealing to make carrying easier and also make the cylinders even less noticeable in-water. Ideally I want be able to do two shallower(esque) dives in a day without having to decant or access a compressor. Owning a 3rd sidemount cylinder to switch out between dives is an option but brings extra cost.

For this reason I think 8.5s is a bit on the "too small side". 10s would a lovely amount of gas (I am fairly confident) but I have never tried them in-water so don't know how they feel / work. They are shorter than 12s so present a new unknown challenge in terms of how to rig them.

Any advice gratefully received

[toby43]

Same height as you, I dive the 8.5L with a Stealth Tec because 12s are an arse to carry a long distance which I have to do. An example of use would be I can do a 30 minute dive at 40M rather than 35/6 minutes on 12s. Trim is perfect and joy to use. You would be pushed to get two dives out of them though. Steels too heavy to attach to waist rings; I hang mine off the square brackets with a tail about an inch and half long. You can extend your options by getting an 7 or 11L AL as a deco/stage which hangs fine beneath the steels, and you can use to extend range/drysuit or deco as you wish. Don't need any lead with Whites drysuit and Arctics. What is the filled weight difference between 10s and 12s? I would go for the 12s if its marginal.

[Mikael]

I say waist D ring but is really a drop D ring and goes fairly far backwards towards the spin. However no buttpad.

Toby how do you manage two dives, do you own more cylinders or always access a compressor between?

[Irnbru]

Mikael - I've used 12s in freshwater and the odd longer duration sea dive (in a drysuit).

In all honesty, bar it being a bit heavier I didn't really notice any difference from steel 7s. You take care of the camband/jubilee clip so that the pillar valve/1st stage are below your outstretched arms (in standing position) when the tin is mounted and it's all good.

If you are thinking of buying 10s fair enough, but I personally wouldn't sell 2x 12s to get 2x 10s - you're losing 460 litres of gas per cylinder so if you ever fancied the odd deeper/longer duration dive the option is still there.

In terms of transportation, most shore dives aren't much more than a few hundred meters from the car so it's a fairly trivial carry. If you are scrambling over rocks down slopes (am thinking "The Caves" in Loch Long or the slope at Gortien Pt.) then a rucksack or cavers tacklebag is ideal.

For slightly longer walks/more committing terrain get a second hand Berghaus Vulcan or Cyclops, it'll take a 12 and some fins etc in one load, then the other tin and drysuit etc. in the other.

In between dive days, go for a walk with some lead or a tin in the rucksack, it quickly becomes unnoticeable and then the whole issue of kit transportation becomes trivial on dive days...

[MikeF]

two 12's are overkill for most dives and for me two 10's are an ideal size for the overwhelming majority of dives. one on it's own is ideal for shore diving, two are a bit short of volume when you go past 70m but OK to 65m ish depending on your SAC as you'll probably have deco stages as well. buy three 10's and swap the most depleted for a fresh one for dive 2.

faber steel 10's are a bit heavy with air / trimix but neutrally buoyant with 15/55. euro 10's are flippin heavy full stop but less obtrusive as they are longer with a smaller diameter.

[Hawk13]

Another option is twin 300bar 7s - which is what I have started using for club dives.

I found that twin 12s were too bulky and cumbersome for 'simple' dives but that twin 7s probably didn't give me the redundancy I needed for longer (maybe 5-10 mins deco) dives. Another SM diver I know used 300bar 7s and I tried them and liked them. If I can't get boat 2 dives out of them I have the option of using an Ali 40 or 80 to give me enough gas for both dives.

And if doing 'big' dives can use my 12s or the club 15s.

Of course, this means I now have a collection of tins but for me it works out. If I didn't have the space / money, I would have stuck with twin 12s and just put up with making 2 trips if the walk to the beach was long.

[toby43]

I got the 8.5ls because they suit the kind of diving I'm doing in Europe ie relatively shallow but with sometimes difficult access. I tend only to do one dive because I'm too damned cold after it to do another. I have no experience of 7s but getting 300 bar can sometimes be an issue. I dont use rails just the square brackets at the back of the belt. The 8.5Ls are thin and long and trim out really nicely. There's enough length at the back to stop me getting head down. I wear slipstreams with them, and depending on undergarments, jets to keep my feet down a bit. If you are after two dives without a refill, I would get the 12s myself.

[Ian_6301]

Silly question, vaguely related but slightly OT:

There used to be a website which listed the buoyancy characteristics of various different cylinders in fresh and salt water...

I think it was Blue Planet or Blue Orb or something?

I've had a google, but I'm lost. Does anyone have the link to hand please?

[Hawk13]

Silly question, vaguely related but slightly OT:

There used to be a website which listed the buoyancy characteristics of various different cylinders in fresh and salt water...

I think it was Blue Planet or Blue Orb or something?

I've had a google, but I'm lost. Does anyone have the link to hand please?

https://www.subaqua.co.uk/cylinder-buoyancy.php

[Mikael]

Cheers guys, quite a lot to reply to here so I'll probably do it bit by bit.

Quick clarification, I own the following cylinders:

Concave euro twin 12s 232 bar
Round bottomed euro twins 8s 300 bar
7 litre ali (usually used for some short deco)

My twin 12s have been great for Scapa and sometimes come out on shore dives but a lot of the time I use the 8s that give me similar gas to twin 10s 232 bar. More difficult entries (such as caves) or just shallow dives in general they are that bit easier to port around on land, lift into the back of the boot so get my preference. My plan is to sell 8s, keep the twelves for deeper dives and get some sidemount tins for other use. The sidemount tins could even double for use as singles for pool / shallow shore dives. I am even thinking I might occasional use just one single steel sidemount at time though that might mean offsetting a bit of weight to balance it out.

I have tried my 300 bar 8s as sidemount cylinders in the pool and the bungee torque method was insufficient to get them to hang nicely to the side of my body. Moving about, rolling onto my back etc there was a fair amount of momentum in the cylinders as they swung about into their new position. I would imagine that a British caving / diving type gear setup with a very short leash would overcome this to some extent. However I have no experience of that and while I currently can access 300 bar fills that may not be the case for long so I am inclined towards a 232 bar solution.

So options are:

8.5s - Lovely to sidemount I am sure but two dives is an issue and limited for single cylinder use
10s - Nice as pool single or shallow open water single - however I have no idea how they are underwater as sidemounts....?
12s - This could be the most flexible option but still have the twin 12s so it is toss up

Ideally I would have something like a tall thin 10 but not sure any one sells that. Also Mike says is a Beaver 10 is very negative so again an unknown quantity (to me) as to how it would behave as sidemount cylinder. According to the web, BTS cylinders are 171mm in diameter and 595mm in length (sans valve). Faber only gives diameter but as this is also 171mm the cylinder length must be similar to the BTS ones.
http://www.slideshare.net/DiveStock/bts-catalogue-2012
http://www.divefaber.com/list/print/...da=9.5&a=11.96


Finally a shorter cylinder might not be silly idea as my drysuit has pockets on the side of the leg.