Twin Cylinder Scuba Weight Setup? #scuba #askmark @dariuszcudera7293
@dariuszcudera7293
Hi Mark
First I world like to thank you for that what you do.
I have question about weight in twinset.
Most of the twinset divers are using only weight attached to cylinders. That is much more comfortable, but is impossible to drop any ballast on event of emengersy situation. Is it just because DIR is giving us redundancy of two separated buoyancy control systems, so we can easier dealing with that kind of problems? Or we should have possibility to drop couple of kilograms? What is your opinion? What system you are using for your double? Many thanks. #ASKMARK
Regards
Dariusz
#scuba #scubadiving #scubadiver
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#askmark
Hello Mark. Thank you for the great content and to the point answers to me previous questions. You really do contribute to the community. I wanted to ask you, since you reviewed Apeks Exotec BCD, and because I already own one (and love it), do you think the BCD would be okay for a DIR equipment setup?
Sort of… there are quite specific requirements for a ‘complete DIR setup’ and the BCD needs to be a full BP/W with a single piece harness.
That being said, if you want to dive a long hose primary donate regulator I’m sure there’s a way to accomplish that. You just need to be able to hold the hose loop down at your waist which can be as simple as tucking the hose under your waistband.
Mark. Thanks for the video. Quick question. I am in the States and haven’t been able to find the “V-weight” you run on your doubles. Who manufactures them, and where can I find them. Thanks for the info. #askmark
Mine is made by a company called Nautilus, I don’t know if they export to the US…
I think it’s mainly down to dive shops making a cast and melting lead into a dedicated lead block. I found a couple of suppliers in the US but, my browser keeps recommending UK shops because of my ip address.
I found some on Northeast Scuba Supply in PA and there are probably plenty others but, I don’t think any will be branded from any of the big manufacturers.
@ScubaDiverMagazine Thanks Mark, I will look them up.
My instructor likes the BerTecSolutions Variable V-Weight.
I don’t completely hate the idea of having 1/3 or 1/4 ditchble, but half sounds like too much. But on the other hand if you’re not severely over-weighted you shouldn’t need the ditchable weight at all, and you may also have added emergency options such as adding gas to your drysuit or large SMB or lift bag.
Mark: Just remember, no good deed goes unpunished! John
I’d suggest that if you have to ditch weight to swim up you are over-weighted. Isn’t that what balanced rig is all about? I’d be slightly concerned by Mark’s rig which appears to have 5 kg on the cylinders and 4 kg ditchable on the belt. Ditching 4 kg will very likely turn into an uncontrolled ascent as you come shallow, exactly where the biggest pressure change occurs. I’m also concerned about the use of a dry suit as the primary buoyancy control. I know this has its adherents but the suit is not designed to be used that way; the wing is.
The v Bar makes sense as does ditchable weight via say bcd pocket weights but a good old pocket designed weight belt has the best easy ditch options to eliminate any likelihood of a rapid ascent, regardless of dry suit or wing buoyancy preferences. I find the weight belt pockets more effective as you can carry/ditch small amounts and position the weight evenly/easier….In my opinion only🤿👌😃
Sounds like you are diving very heavy Mark, diving a balanced setup you should be able to swim up. (Been demonstrated a few times too)
With twin 12s your air weighs about 6,2 kg. Assuming you don’t want to bolt up at the end of your dive, this is weight you need to bring as lead to be neutral at the end. Add a dry suit and a thick undersuit and you’ll need quite a bit.
He’s not diving with a single 10 and a t-shirt ;)
TLDR, If you don’t know how much lead weight you need for any new equipment configuration. Do a proper weight check.
Isn’t it dangerous not being able to fast release all this negatively boyent setup
Quite the opposite. If you ditch a significant amount of lead at depth you are likely to enter an uncontrolled ascent as you come shallow. This is why correctly weighted technical divers typically have no ditchable weight.
I only use 8 pounds in a 5mm wetsuit with a 15L LP steal. I. My dry suiti only use 18 pounds. I have never dove doubles, but I think I will not need any lead. Thoughts
As I’m sure you know, you choose your weight for being neutral at 10 feet with the cylinders being at minimum, typically 50 Bar. A typical steel cylinder at that pressure is actually more or less neutral in salt water and about 1 kg negative in fresh. Add in the weight of valve and reg and you are adding about 1.5 to 2.5 kg/3 to 5lb compared to your single cyl negative buoyancy. So all else being equal you can likely lose that much lead, but you will still need some.
DIR does not “give you redundancy of two separate buoyancy control devices”. No DIR diver would consider the drysuit as a buoyancy device, and it is perfectly fine to dive wet under the DIR philosophy.
What DIR does promote, is the use of a “balanced rig”. This refers to having a rig that satisfies two extremes: 1) Being able to maintain a depth of 3m with 50bar in your tank. 2) Being able to swim your weight up from the deepest point of the dive, with full tanks and a failed wing.
The first thing that you would notice, is that this forces you to carry only the minimum amount of weight in order to hold the final stop safely – no overweighting like some OW divers.
The second, is that you soon find out that some gear combinations are impossible due to them being unsafe – the classic example being steel doubles with a wetsuit. Due to the loss of buoyancy caused by the compression of the wetsuit at depth, and the heavy weight of full steel doubles – there’s no way you can recover from a failed wing. Notice though – it’s not that we consider the drysuit as redundant buoyancy, it’s just that it’s innate buoyancy doesn’t change, and is bigger than that of a wetsuit to begin with.
I recommend watching DoktorBen’s video on a balanced rig to learn more.
A dry suit is most definitely a redundant buoyancy device. If your wing totally fails you can easily achieve neutral buoyancy with your suit. I would never do a tech or cave dive without a dry suit. I know some people do but I hope they have the foresight to use a redundant wing setup.
@Erik when diving technical with wetsuit I’ve been told you have to demonstrate you can establish neutral boyancy using your DSMB.
@Erik that’s ok, you do you – it’s just not DIR.
It is worth noting though, that achieving a balanced rig with full tech gear can be close to impossible with a wetsuit, so most DIR divers would go dry anyway.
@Niklas like I said – when diving a balanced rig, there’s no need for such shenanigans. Even with a failed wing, a truly balanced rig would allow you to come back up from the deepest point of the dive.
@Daniel Ricardo well, it’s for sure way easier to do deco stops if you can be neutral and don’t have to swim to stay at a stop (also not best for deco as you work at the same time)
I’m doing my stage diving with dry suit, my instructor said if we where in wetsuits we would need to demonstrate we can perform deco stops with simulated broken wing using DSMB to find neutral boyancy.
# Ask Mark
What’s the scoop on bubbleless/ rebreather systems. IE kiss n such and chems involved n maint… Yeah long question…oops
Thinking to migrate to no bubbles
You’re looking at Closed Circuit Rebreathers or CCRs. The basics are you have one small cylinder of Oxygen and one small cylinder of diluent such as air. The air that you breathe circulates in a loop, the exhaled breath passes through a scrubber that cleans the CO2, then the volume of the breath is topped up by diluent, the O2 is topped up by the Oxygen cylinder and you inhale it again. This repeats until you run out of one of the resources or the scrubber gets saturated.
If you dive frequently they become cost effective and have a few benefits over Open Circuit.
Hi Mark Thanks for all the great content. 👍🏻 My wife and I have just become Dry Suit drivers, we previously only dived in warm water locations but have decided to exploer some dive sites with much cooler water. What is the best way to transport dry suits on a plane. I have an Apex Thermiq advanced and my wife has a custom crushed neoprene made by O’ three. Thanks #askmark
My main focus is the zipper and any rigid parts such as cuff rings. I pack and pad my suit to protect the zipper from pinching. Pack your suit as if there’s going to be lots of other bags on top of it and you want to maintain a flat zipper to prevent damage.
When I travelled with my old suit with a brass zipper I just packed it in a tough duffle bag and it was fine. Just protect that zipper and any hard parts and you should be alright.
Thanks for such a speedy reply 😀 @Scuba Diver Magazine
Sorry….I meant V-Weight! Hope I can buy them over here.
Where can I buy a P-Weight? I am in USA.