Big Heavy tanks!

[DAJ]

I only use 130s with Y valves for my single-cylinder dives. It's not that larger cylinders are a PITA, it just takes a little time to figure them out compared to other smaller cylinder options. OP, if you do go with larger cylinders, take the time to get your weights figured out and not just use what you use now.

One of the first tests I use to put my new dive team members through was taking them down to 30 feet or so, releasing all the air from their BC, and have them swim their gear out without kicking off the bottom. More times than not, the diver would get about 10 feet off the bottom and then just hang there kicking away and not going anywhere. I don't use any weights with my setup when I dive 130s.

I am also not one of these "must return with a near empty tank" types. I plan the dive and dive it. whether I return with 500 or 1,500 left in the cylinder, it's something I don't worry about.

 

[Ken Reid]

A bigger tank can help increase bottom time. An argument can be made that it increased the drag because of more air in the BC....thing is, if you are weighted right, it is all a trade off. Also a lot of other factors play into it like what other gear are you wearing. Personally the drag created by the extra size in the tank is negligible for the kind of of diving we do here.

Others have hit the nail on the head....

1. Relax enjoy the learning experience
2. Build up your time underwater, this should mean you relax more
3. Work on buoyancy skills, finning techniques...the basics... they will help
4. Spend some time in the gym...this is often overlooked. The better shape you are in, the more comfortable you tend to be which means the better you make out underwater.

 

[KenE]

Larger tanks can be your solution, I dive a HP117 and enjoy it. I too consume gas, not like I used too, but still more than most. I find that taking a couple minutes before descent and a couple minutes at depth to decompress makes my gas last longer than any other solution. The time at surface helps reduce breathing rate and stress of getting the kit on and rushing. The time at depth helps reduce the stress of descent for new divers, adjust/tighten weight belt if needed, but just relax get your bouyancy then start your dive. You will find that your consumption drops if you take the extra time and stop worrying about what other think, don't worry about your consumption during the dive, enjoy the dive and relax. Soon enough you will come up with more gas than your buddy. Diving is fun, keep it that way, don't worry about it.

 

[jordaof]

Thank you all for your opinions based on your knowledge, it helps a lot novices like myself, I will take in consideration all advices and will try out different tanks bigger than my 12 liter, and also.. will take some exercise.. it helps even if a little, in air consumption ;-) I'm also constrained by the max weight my BCD Mares Rock Pro can carry, they tell that the max will be around a 18 liter, around 41 pounds or 19 kg, and more important, how I adapt my meager skills to a bigger tank. I will try out a 15 liter and a 18 liter next week, than I will have some kind of opinion. Thank you all!

 

[_sgm_]

Learn early if you need steel or want steel because after years diving Steel and putting steel in multiple configurations thinking the weight of the tank would be my saving grace vs weight belts...
once I went to twin steel that was my downfall.. so now I am selling all my steel tanks..
Before you make my mistake know your air needs and find the cylinder which works best for you ( weight wise )
Consumption of air is relative to work and force.. I can hold a sac of .54 2.7RMV@5ata or 15L 75RMV@5ata.

remember how to calculate SAC and RMV
SAC will be gas consumed at the Surface
Example ( you go to 10 meters with 200 bar for 90 minutes and ascending with 35 bar ) assume a 11L tank 2200L @200bar you consumed 165 bar in 90 minutes ( volume consumed ==165bar x11L tank ) 1815L
now to get your SAC
1815(liters)/90(minutes)/2(atmospheres)
SAC=10.8L
now RMV will be SAC*ATA so if you are doing a dive to 30 meters how much Air to you need...
RMV@2ata 21.6L
RMV@3ata 30.25
RMV@4ata 40.3L
Once you know how you breathe then you will know how much you need to bring with for the length of the dive you want to do..
simple tips to help you decide what you will need.

 

[crofrog]

Learn early if you need steel or want steel because after years diving Steel and putting steel in multiple configurations thinking the weight of the tank would be my saving grace vs weight belts...
once I went to twin steel that was my downfall.. so now I am selling all my steel tanks..
Before you make my mistake know your air needs and find the cylinder which works best for you ( weight wise )
Consumption of air is relative to work and force.. I can hold a sac of .54 2.7RMV@5ata or 15L 75RMV@5ata.

remember how to calculate SAC and RMV
SAC will be gas consumed at the Surface
Example ( you go to 10 meters with 200 bar for 90 minutes and ascending with 35 bar ) assume a 11L tank 2200L @200bar you consumed 165 bar in 90 minutes ( volume consumed ==165bar x11L tank ) 1815L
now to get your SAC
1815(liters)/90(minutes)/2(atmospheres)
SAC=10.8L
now RMV will be SAC*ATA so if you are doing a dive to 30 meters how much Air to you need...
RMV@2ata 21.6L
RMV@3ata 30.25
RMV@4ata 40.3L
Once you know how you breathe then you will know how much you need to bring with for the length of the dive you want to do..
simple tips to help you decide what you will need.

SAC and RMV (respiratory minute volume) refer to the same thing. They’re both at the surface. Depth consumption rate is term for gas used at depth.

Gas Planning 101: How To Calculate Your RMV - Alert Diver Magazine | DAN Europe

Respiratory minute volume or RMV, also referred to as SAC rate (for Surface Air Consumption) or SRC (Surface Consumption Rate) is the volume of breathing...

alertdiver.eu

 

[_sgm_]

SAC and RMV (respiratory minute volume) refer to the same thing. They’re both at the surface. Depth consumption rate is term for gas used at depth.

Gas Planning 101: How To Calculate Your RMV - Alert Diver Magazine | DAN Europe

Respiratory minute volume or RMV, also referred to as SAC rate (for Surface Air Consumption) or SRC (Surface Consumption Rate) is the volume of breathing...

alertdiver.eu

I got my hands slapped using the terms interchangeably ( SAC / RMV ) .. else why are they referencing different things? Ergo multi deco is wrong in how it uses the terms...
I could sit and argue the fact, but I will just say Ok to you and good day

 

[berndo]

so now I am selling all my steel tanks..

Nobody in Europe uses AL tanks... they suck compared to the steel tanks we have. The Euro tanks are all 200-230 bars and aren't as heavy as US HP tanks. Most 15l tanks are close to neutral when at 30-50 bars. So picking a tank here is a no brainer. You either use a 10l, 12l or a 15l if you need some more gas. There isn't much point in even calculating sac rate as it doesn't change anything or give you any useful information. When you hit return pressure you head back home.

 

[amado_sarhan]

Nobody in Europe uses AL tanks... they suck compared to the steel tanks we have. The Euro tanks are all 200-230 bars and aren't as heavy as US HP tanks. Most 15l tanks are close to neutral when at 30-50 bars. So picking a tank here is a no brainer. You either use a 10l, 12l or a 15l if you need some more gas. There isn't much point in even calculating sac rate as it doesn't change anything or give you any useful information. When you hit return pressure you head back home.

Many places in Europe use AL. Calculating SAC rate is not useless or pointless.

 

[berndo]

Many places in Europe use AL.

Where are these many places? I'm calling BS.
This is basic scuba. You swim along a wall or whatever and return when you hit return pressure. Knowing your sac rate doesn't change anything.