Let's Talk About Cylinders | Deep Dive

[@simplyscuba]

Chapters [1:23] Size [5:37] Pressure [7:16] Material [8:27] Markings [10:32] Valves [15:14] Bottom [15:57] Colours [17:16] Finish [19:26] Testing [22:08] Care [25:14] Twins [27:25] Buying Tanks [30:15] Stickers [33:03] Fill [36:52] Travel [42:03] Inverted

[@Richard-x5h8i]

Good advice and well presented Mr beard certainly knows his stuff..new and old divers can all get something from this well presented series and no I have not been paid to say this I am a uk diver of some 50 years starting when I was 20years old.....

[@Teampegleg]

Common US tank sizes and common purposes for them. Aluminum: Anything below 20 cuft: Shallow bailout/pony, argon, rebreather bottles 30: Mostly bailout/pony 40: Deco bottles, and bailout for anyone that realistically calculates their SAC/RMV 63: Smaller primary tank, mostly for women and children 80: The gold standard, what you will get if you rent a tank. Also used a stage bottles for tech divers, and as BM doubles for warm water. 100: Uncommon, but are still available often when an operator says that they have larger tanks it is one of these. Steel: High Pressure (3,442psi/232bar) 15 and 23: CCR tanks, often labeled by their metric water capacity, 2L and 3L respectively. 80: Smaller tank used by smaller people, about the size of an AL63. These are often only personally owned. 100: Pretty much the standard steel tank, about the same size as an AL80. When an operator says they have steel tanks it will probably be these. As very commonly used a backmounted doubles. Everything else: Less common, but still available Low Pressure (2,640psi/180bar) Low pressure steels are pretty uncommon, most people buy HP steels due to capacity vs size/weight. The are most commonly seen in Northwest Florida, Cave Country, where they are given cave fills to around 4,000psi. These are sold mostly as painted tanks, as the galvanized tanks are heavier. 27: CCR tank, sold as a 4L tank. 50: Becoming more common, great smaller tanks for shorter dives used both sidemount and BM doubles. A buddy used them as bailouts for his CCR. 85: Pretty much the standard sidemount tank, sometimes used as doubles for smaller divers. 95: Sometimes used as sidemount tanks, but isn't that common anymore. In the past they were popular BM tanks. 108: Pretty much the standard backmounted doubles tanks. And if anyone is wondering how to do dissimilar gas matching (ie making sure that we have enough reserves for everyone) we use "tank factors" to quickly convert from pressure to capacity. It works pretty much similar to metric. So I know that my LP85s will have 6.4cuft for every 100psi of pressure. So if I have a 3,600psi fill, I have a 1,200 third. So I have a 76cuft third, I hand that to my buddy running 108s. He takes that and divides that by his tank factor (which for all LP10Xs we use 8), so he only has 900 psi to work with to ensure that he never uses more than my reserve third. So his turn pressure if he starts with 3,600psi is 2,700psi.

[@aralverson]

Great deep dive! So much information that went way beyond what I was expecting. If you're a new diver don't worry about getting overwhelmed. Mark did a great job at breaking down the most important tank features in the order presented in the video.

[@markyuile4571]

Thanks Mark, this a brilliant comprehensive explanation. I have been searching for such an explanation in my research prior to buying tanks. In the end I went with 15 litre steel 230 Bar tank for exactly the reasons you mentioned. Great to have that confirmation. Thanks as always great to see you back in the blue shirt!

[@scottinnes7376]

Just getting back into diving after a long break. You’re videos are amazing, my go to for current info, and really useful for in-scene opinion. Fully subscribed!!!

[@GhostCaver]

For florida in the US, visuals expire after 1 year, hydros are 5 years, the visual is marked by a sticker with dates and o2 clean status, hydros are stamped in the shoulder of the cylinder with a month special stamp in the middle of where it was hydro tested and then year Like: 5 ☆ 17

[@shotnutella3602]

Thank you man I'm going to start suba diving next year so this helps alot.

[@vegeyballs]

The situation with plugs you mentioned is called dissimilar metal corrosion. If you want to use a metal plug make sure its as close to type of metal the valve is made out of. If your unsure of what metals will have the least effect google the galvanic scale. The closer they are on there the safer you are.

[@KB-gd6fc]

Here in the US we like to make tanks sizes as confusing as possible.

[@seikibrian8641]

What's confusing about the US system? It tells you the actual amount of gas in the system when at the rated pressure, rather than just how much volume the tank displaces. Knowing that I'll get about 1.5 times more dive time from my steel 120 than from my aluminum 80 is useful information. I couldn't care less that a tank displaces 11 liters or 15 liters or whatever. Further, my low-pressure 120 and my high-pressure 120 both contain the same breathable volume of gas, even though they have different dimensions. That's also useful information, since dive time is directly related to gas volume but has nothing to do with cylinder dimensions.

[@joshs3916]

😂😅

[@jameson1239]

@@seikibrian8641 it’s measured by internal volume e.g how much stuff you can fit in under one standard atmosphere not external volume

[@bloodymarvelous4790]

@@seikibrian8641The rest of the world has the benefit of using the metric system, so it's really easy to calculate the actual amount of gas in the system. Having the internal volume as a measurement also makes calculating your RMV so much easier.

[@juniperreborn7956]

Very informative, filled in some very useful knowledge gaps I didn't know I had. Thank you!

[@joet670]

As Always, Good Info 👍🏼 I just purchased a HP Steel 149CF (19L) Cylinder It's big, but I'm a bigger guy (6'-3" 250lbs / 189cm 113kg) I've suited up in it and the weight isn't an issue for me. I'll test it in the water this weekend. The Buoyancy Swing is a bit high -9 / +2, but I'll see how to compensate for that. I think the Cylinder fits my Physique the way an 80CF fits an average size person. I tried to find videos of people using a 149CF (19L) Cylinder but I couldn't find any.

[@bombousboy]

Just excellent. Well done and thank you.

[@cavemansee7110]

Great thanks for the info it’s been awhile since thinking about this stuff so a few pennies have dropped in my head again cheers

[@M.S.film.s]

Man amazing video even though I am not done with it. No WAY you did this in one sitting. Amazing job

[@debbietaylor5332]

Reading through the comments it shows to me how training has changed. Back in 1984 one of the sections in the BSAC novice diver qualifications was the " Equipment lecture " which you had to get signed off and most of the time in that lecture was spent on tanks, types, inspections, markings, safe handling and everything else you covered. It surprises me that very obviously qualified divers in the comments show they have holes in their knowledge base, so in this respect you must be congratulated on a job well done :) .Sign of the times I guess but then I only moved up from an ABLJ to a BCD two years ago even though I have been advanced since 94 , loved my buddy arctic and twin 10's

[@dbayboyds409]

Great comprehensive video! Thank you!

[@bleebu5448]

galvanic corrosion is what fuses dissimilar metals, like brass and and steel, say for instance in a 20 year old chevy brake line.

[@walters849]

Currently using Faber 15ltr steel cylinders as I’m still a gas guzzler and go through air as if my life depended on it. And how did Sean let you get away without the “tanks for watching”?

[@seymourpro6097]

NEVER have an alloy cylinder powder coated. It's a lovely hard wearing finish that looks good for a long time BUT the powder coat oven is set above the alloy's tempering temperature and the alloy becomes very weak. Someone tried this at my Uni dive club at great expense.

[@matthijsnibourg891]

I do have 12L 300bar and 10L 300bar steel tanks, i just top them off just before diving (got my own compressor) so they will be closer to the 300bar, i did buy 300bar cilinders because my gas consumption whas more than other divers but after taking more dives my consumption went down and i mostly still have a bunch of spair air in there now.

[@HypnoticAbyss]

Woah didnt realize you guys were back, haven't been getting notifications.

[@bobolthuis6309]

Another newbie getting an awesome heads up! Thank you and carry on please.

[@thomasw5430]

Great episode Mark! I am in the US, and a bit of a gas hog- so I am currently diving with single steel 100, looking to go to doubles next year once i finish my AOW certification!

[@Yggdrasil42]

Take a look at sidemount as well. I feel it has some benefits over backmount doubles, such as a very easy horizontal trim due to the lower center of mass. Good info can be found at sidemounting.com and scubatechphilippines.com

[@clarkeysam]

In my opinion you shouldn't be looking at twins yet, if you've not finished your advanced. That'll be trying to fix a diving problem with equipment e.g not what you should be doing. Get diving more, the more you dive the less air you'll use. On each dive consider how your trim and buoyancy is, if you do not move at all what happens? Most inexperienced divers will sink as they're often overweighted and don't have their buoyancy dialled in. Then only consider twins if you still need to once you've got an awful lot more experience.

[@thomasw5430]

@@clarkeysam yeah I know. I am going to hold off on that until I am ready. No rush right now. Just mapping out where I want to go with this hobby.

[@CJ-vi7ku]

Very informative. Thanks much!

[@TheAquaticGeek]

Thanks for the info, exactly what I needed!

[@danielsmith5325]

Thanks enjoy watching your vids relatively it helped a lot new to diving and slowly purchasing my gear. I’m looking at the faber 18l 232bar (x2 for double boat dives) as my next purchase I tend to use up my air quickly on the 12l tank and with a 5 hour drive to the coast each time would prefer to make the dive last as long as possible.

[@michalpotok]

Bouyoncy gathered from used air (and a need to compensate by lead) is exactly the same for steel and aluminum tanks (if only volume of used air is the same).

[@SimonAmazingClarke]

Excellent training.

[@jabadoodle]

Watched it all! Very informative. Thank you :-)

[@SavedByFaithInJesus]

FYI. From USA. Went scuba diving in the Bahamas in 2014, (Intro to scuba, kinda thing, Stuart Coves ((Absolute Recommend)) LOVED IT!!!!!!!! I Didn't Equalize correctly on way down, when back on the boat, hocked a blood loogy the size of a baseball and had HORRIBLE headache for a day.... Still, LOVED IT!!!!!! I have some locals that train... $$$$ and Time is the issue. Thanks for this video and ALLLLLL of the other videos. I've got 5 hobbies.... and not enough money or time......

[@bloodymarvelous4790]

Mostly $$$$ is the issue. SCUBA - noun scu·​ba Definition: The art of throwing money into the ocean.

[@allanclell]

Havnt actually been on a dive for nearly 30 yrs. used to have alloy 88cf tanks and had a couple of 72 steel . In Australia

[@skisunshine]

Interesting vid, thanks. Could have done with a few pictures to help with what you were talking about too.

[@Justins-Adventures]

Heya mark, a couple pictures would be useful for some of the topics. Cylinder markings in particular

[@javierfranzoni4684]

Hey Mark, thanks for the video. Why did you say that aluminum cylinders are better for stages/ sidemount? For me it’s quite annoying bringing more weight to compensate their buoyancy variation. I understand that in warm salty water they use aluminum cylinders to avoid corrosion, but in the rest of the cases it doesn’t make a lot of sense to me. Could you please elaborate more on this topic the next Q&A? Thanks a lot!

[@Yggdrasil42]

For deco cylinders or stages I'd always get alu since deco cylinders should be removable during a dive. Alu 12L will get about 1kg positive at 50 bar which is barely noticeable. This means you can pretty much count them as neutral for your weight planning and you can easily stage them at a wreck or cave somewhere or move them from your side to your butt or to a line without it affecting your overall buoyancy and trim. In the sidemount community the consensus for regular cylinders is pretty much: alu for wetsuit, steel for drysuit (the additional weight of steels offsets the buoyancy of the drysuit and undersuit). However heavy steels (e.g. 14.5 kg)become unwieldy and you can't "gun" them anymore. A good alternative is lightweight steel. Brands like Vitkovice sell them in ranges from 12.x to 14.x kg, both convex and concave. I personally have a set of 13.1 kg. They allow me to dive drysuit with 8kg of lead instead of 12kg I'd need with alu. But they're still light enough to be manageable in restrictions. Can't drop them since they're part of my weight system, but I can gun them if needed.

[@МарияАкинфиева-л2у]

Very informative, thanks a lot! It would be nice though to visualise the information a bit more for beginners to understand it better

[@seikibrian8641]

Tank: noun. A receptacle, container, or structure for holding a liquid *or gas.*

[@bloodymarvelous4790]

Not sure where you got that definition from, but both Merriam-Webster and the Oxford English Dictionary define it only as a container or receptacle for liquids. Then again, they're missing several definitions in common usage. No mention of "to tank" meaning to absorb damage.

[@seikibrian8641]

@@bloodymarvelous4790 If I type "tank definition" into my search bar, the first thing that comes up is "tank [taNGk] NOUN a large receptacle or storage chamber, especially for liquid or gas." If I scroll down to the Cambridge Dictionary, I get: "tank noun UK /tæŋk/ US /tæŋk/ tank noun (CONTAINER) a container that holds liquid or gas."

[@seanglendenning3122]

Hi Mark, great video thank you. I currently deciding whether to buy steel or aluminium cylinders for deco. I currently dive twin 12 fabar, i know you touched breifing on there differences, however i wanted to know how much buoyant do aluminium cylinders get ie is it enough to create a rapid ascent? I will be using the deco cylinders for nitrox 50% any advice you may have would be greatly appreciated.

[@Yggdrasil42]

For deco cylinders I'd always get alu since deco cylinders should be removable during a dive. Alu 12L will get about 1kg positive at 50 bar which is barely noticeable. This means you can pretty much count them as neutral for your weight planning and you can easily stage them at a wreck or cave somewhere or move them from your side to your butt or to a line without it affecting your overall buoyancy and trim.

[@seanglendenning3122]

@@Yggdrasil42 hi thank you for your advice thats good to know, so you would go for aliminum 11 ltr instead of 7 litre then?

[@nyax129]

everything you didnt know you needed to know about tanks.

[@undisclosedperson3871]

I have dumpy 12s. They're my favourite thing ever!

[@DiverTweed59]

In Australia, the tank must be hydrostatic tested every year.

[@Teampegleg]

I am pretty sure that M25 is pretty much isolated to Europe, and countries where most of the tourists come from Europe (like the Red Sea). the 3/4" NPS is the most common tank threads I've seen around the world. There is an increasingly uncommon 7/8" UNF threading that was for true HP steel tanks (3,500psi or higher) in the US to ensure that you never put a lower pressure valve on it. Those valves were non-convertible to yoke and were 300bar DIN only. But with the adoption of the 3,442psi HP steel tank, those tanks are no longer made and they are becoming increasingly uncommon.

[@kmcq2255]

Thanks but it would really help to show us the tanks as you talk about them.

[@rayamis9509]

What is TOO FAST tank filling. How long should it take to fill a 15 l tank that is half full already. (WP 232)?

[@Teampegleg]

General recommendation is 300 psi (20 bar) per minute. At least with the fill station I use you can hear it when you have it just right.

[@kyleanderson8224]

In the Navy we would do 400psi a minute if cylinders are submerged in water, 200psi if not submerged.

[@shoreangler3383]

I'm a beer tank. Lol 😆

[@Zvona555]

Great video. I'm just about to buy my second tank and your advice gonna help me a lot. Me and my regular buddy currently use 15l/300bar tanks, but it isn't the best solution for two reasons: 1) diving centers where we usually dive (in Croatia, Europe) can only fill up to 232bar, so we can't use the full potential of our tanks. 2) I always use somewhat more air than my buddy, so we usually end the dive with about 30bar difference. My solution would be to sell my 15l/300bar and buy 18l/232bar. Later, my buddy may sell his 15l/300bar and buy 15l/232bar. One important topic may be added to your great video - the tank weight. We need to carry these things around a lot before even entering water. By doing my own research, I discovered that 18l/232bar (steel) has almost the same weight as 15l/300bar (steel) - when you get Archimedes principle into account, 18l/232bar(steel) is even slightly more buoyant than 15l/300bar (steel), especially when on low pressure?

[@joshs3916]

Have a 149 and 133 HP, not small, but we are diving deep in the states

[@willsmooth45]

Lmfao KZbin seems to know I just bought a new tank too ! Lmao I got a purple anodized aluminum 80 for 120 bucks!

[@bren8168]

Does your shop not sell cylinders?

[@bloodymarvelous4790]

This was in the Simply Scuba days. Mark doesn't have a shop, and Simply Scuba (now defunct) was an online retailer. Most shops won't ship cylinders. You need to come pick them up. So the answer is "no", 'his' shop does not sell cylinders.

[@piotrkubiec5549]

Important thing: 10l 300bar is NOT the same as 15l 200bar. About the colour: DON'T paint the tank red (reserved for fire extinguishers) or "deep blue" (reserved for propane).

[@MegaBoilermaker]

The old American standard was 71 cu ft.

[@leczgdzietoniewiadoma2753]

I thought tanks are used to invade poland

[@joshs3916]

🤗

[@garywebber58]

Ok, you start by telling us the different between tanks and cylinders and proceed calling them tanks ? Really.

[@nitrovaari]

Just one correction: Steel cylinders are actually lighter than comparable aluminium tanks. Yes, in the water they are less buoyant due to thinner walls.