Cylinder Set Ups-Confused of Hayling Island

[JamieG]

Originally Posted by MonkeyPony

Why do you think you need to change and what do you hope to achieve by changing?

If you're happing with the diving you're currently doing and happy with you're current kit why go through the cost of changing.

I was quite happy with a single 15l for the first dive and a single 12l for the second, but lately I've been thinking that maybe I could do with some redundancy.

People keep telling me diving 30m+ (which some of my dives are) means I should be using a twin something or other.

Like I say its all getting rather confusing now.

[MonkeyPony]

Originally Posted by JamieG

People keep telling me diving 30m+ (which some of my dives are) means I should be using a twin something or other..

O.K, this is pretty much bollocks. With good buddy skills and good dive planning and execution all you really need is a pony (if that).

Originally Posted by JamieG

I was quite happy with a single 15l for the first dive and a single 12l for the second, but lately I've been thinking that maybe I could do with some redundancy.

Then what you need is a pony. Move to a twinset if you want longer dives and longer deco but dont forget that the majority of U.K diving, even within the 30-40 meter range is done on a single + pony. Its easy to read the forums and think 'Blimey everone is using twins, maybe thats what I need' but its bollocks really.

If you're comfortable doing what you're doing stick with it. Save the cash. If you want to move into longer bottom times and deco then look for twin 12's as they give you the most scope.

Just my 2p and I'm sure people will disagree with me but there you go. Do you dive within a club?

[Blu DL]

so many configs - none of them 100% right..... none of them 100% wrong!!

I dive indie twin 12s mostly on air - will dive a single 12l down to 25m if not doing any deco diving and in good vis (ie not uk). The twins aren't really for depth or longer dives as such - just want my 8 yearold to have a daddy - so I'm double safe and carry a range of redundant items - spare mask, torch, dsmb and reel, depth gauge, watch in addition to usual stuff. One cyl has drysuit hose, other cyl has jacket - thus giving some buoyancy redundancy too.

I suggest IMHO next step for you is a 3l pony on the 15l if doing 35m diving. If going much deeper for longer u really need to realise a 3l pony at 40m will last only 7 mins - but will give you 21mins at 6m (20l min at 1bar). I wouldn't feel comfortable racking any more than 10mins of deco on a single and a pony. You can't solve your own problems without redundant gas - essential IMO in UK waters - so easy to lose a buddy in low vis- been there..... done that....

Diving from a rib - twins are impractical due to weightt

If you get a pony - regularly practice switching to it every training dive. A chap in our club - sport diver of 20yrs - VG diver- had a freeflow and although has carried pony for 5 yrs, never even thought of switching to it when cyl had gone - instead he did textbook air share ascent with buddy (without issue). In a panic you do the first thing that comes into your head- lucky some of the training kicked in!!

[Sipadan]

Originally Posted by JamieG

Hi Andrew what is it about the 10s you find hard to trim please? Is this with a set of Euros or Fabers?

head down and i mean standing on my head if i relaxed in the water. fabers were the culprits. i believe euros are better, but i haven't tried them.

having tried all of these set ups, i don't think there is a perfect solution. the nearest i've got is twin 300 bar 7s for shore dives/single boat dives and twin 12s for back to back boat dives. it's expensive in terms of outlay and servicing and while the twin 12s are fine in the water, they are no fun outside of it.

for the type of diving you describe, i think a 15 + pony is fine. a twinset certainly isn't overkill, but why go through the pain/expense?

andrew

[JamieG]

Thanks for the input guys.

I do belong to a club and dive with them, but also dive outside it with a mate.

In the past I had a pony which was okay but did make me a bit 'lop-sided' so not sure I want to go back to that.

To be honest 12s are not what I'm looking for, my knees are not great.

I'm certainly warming to independent 300bar 7s (with a spare one in the boat if I'm doing a second dive) Is there a way of setting these up on my back plate without metal twinning bands so I can swap a cylinder for a second shallow dive?

[Rookie]

Originally Posted by JamieG

I'm certainly warming to independent 300bar 7s (with a spare one in the boat if I'm doing a second dive) Is there a way of setting these up on my back plate without metal twinning bands so I can swap a cylinder for a second shallow dive?

Does your backplate have cambands? If so, buddy twinning bands will be perfect, and cheap(ish). If not, you can get twindipendant adapters which will bolt to your backplate.

Personally, I've ordered a set of Euro (beaver) 10's from Niknaks (decent bands and manifold see, not the beaver ones). The Fabers were a bit of a pig trim wise, and I'm hoping these will be better. For me, there was no advantage in 7's, and with my dodgy legs and habit of rib diving, 12's are far too heavy to lug about.

Phil

[Blu DL]

yes - I was tempted by 300bar 7s but there is issue of finding somewhere that can blow to 300bar (most blow to 232) and also the twin 7's are pretty heavy once they are fully charged. Also, due to gas compression the laws breaking down after 230bar the actual amount of gas you get into 300 bar is not double what you get into 150bar (molecules can only get so close) Not sure what the loss is - anyone know?

A good system is to dive 232bar twin 10s and then have a 15l cylinder with a charging whip you can decant from in the boat. After the first dive, if you have 120bar in the 10s a decant from the 15 will bring it up enough (170bar) for a shallower second dive - You can also decant in the same way with 300bar I presume but have never seen anyone do it.

It's worth noting that 300bar 7s will be considerably lighter at 50bar. Weighting needs to be properly considered - I would guess at 2kg per cyl - does anyone know the actual weight change? / have a formulae??

[Blu DL]

ooh ooh - this is a great article for you to read :

300bar Cylinders

His knowledge is greater than mine (ie - some!!)

[JamieG]

Originally Posted by Blu DL

ooh ooh - this is a great article for you to read :

300bar Cylinders

His knowledge is greater than mine (ie - some!!)

Thanks thats interesting stuff - but just when I thought I had things sussed with the independent 300 bar 7s I'm now back where I almost started.

Basically it's going to have to be independent 232bar 10s, or 7s or 300bar 7s - christ why does everything have to be so confusing these days? I guess they call it progress eh!

[Blu DL]

yeh - there's a trade off between a bad back and not enough gas / less safe!!
I went for the bad back (lol) 12l twins

I looked at 300bar 7s a couple of years ago and was disappointed to find out it isn't the panacea I hoped it would be. damned physics!

You need to accept that there isn't a 100% right setup - or a 100% wrong one- all designs are a compromise - You need to decide which features you MUST have in your setup and which features you WOULD LIKE but aren't essential.

For me, safety was paramount over everything and I am a ham fisted fairly strong bloke so I decided I could put up with twin 12s. My diving suits twin 12s down to the ground as our club tends to do 35m in morning and 20m in afternoon. Twin 12s have enough gas to do 30-40 min divetimes for me without having to change cyls on the boat (ie I am lazy!!)

I think twin 10s with 15l decant or 15l and pony is a reasonable pair of options. You could even dive single 12l /15l with a 7l stage clipped on your front - I suppose - but remember this give you no buoyancy gas backup. One solo diver I shared a boat with in Lyme had a dumpy 7l strapped horizontally across his belly - this had nitrox 60 in it for deco - he had twin 10s air backgas - seemed to work for him...

I am not trying to confuse - only inform. I sincerely hope I am doing that.
Make a list of must haves and would likes - see if that helps you. The answer is to gradually build a setup that works for you - but the gold rule is change ONLY one thing at a time - you don't want to taskload yourself too much. See if you can borrow kit to try out in a quarry to see if you get on with it before you buy. MAke sure your buddy is experienced and can help you if you need it

There's my 10p. best of luck