Big guy... big tanks?

[crookshanky]

When I first started diving, my gas consumption was terrible. I was turned on to sidemount (SM) and absolutely loved it. Not only does it give you double the gas but also redundancy. As others have mentioned, in some parts of the world you will be limited to one size cylinder (ie. Al 80) so a larger single cylinder may not always be an option.

I enjoy not having to rely on a buddy, especially when paired up with a complete stranger. This gives me freedom underwater as well as I don't have to worry about staying close to my redundant gas (buddy) as it is always within arms reach.

The extra gas may also relieve the stress of trying to control your high gas consumption. My best advice is to not concentrate so much on your breathing but to try to relax and stay calm while diving. Improved consumption will come with experience.

I only dive SM now, including open water. It was great to have on my recent Raja Ampat liveaboard. While the rest of the single backmounters ran low on gas and had to go up, I got to stay down and play with the mantas for an extra half hour. If you're interested, there are many agencies that offer a recreational SM course.

 

[NAM001]

Prunefoot. You don't need as big of tank as you may imagine. the 115 is a good recommendation.
the al80's have actually 77 cuft in them. so at 500 psi they have round 16 cuft so you have 60- cuft to use on the dive. So to get a tankand subtract about 15-17 cuft should give you tha amount of usable air on the dive and still come up soth around 4-500 psi. Given that a 130 will give you twice the dive air than the al80 a 108 would give you an extra 50%. Look at the huron tank specs at weight. the al80's are about 35# the al100 about 45# the lp108 about 41 the lp120 45#. And yes many will over fill if you ask them to. a 3k fill on a lp tank is normal to find. that would make a lp108 hold in the 120's. That little bit of over fill is about 13% more air (2640-3000)

Here is a link Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

look at the oms 121 and 135. the oms 121 is actually 125 and the list says the 135 is actually a 131. Even at an normal fill the 121 is right at twice the air of a al 80. I have 3 oms121's among others. Dive in shallow lakes all day with them. One place I go to fills are 8$ whether it is a 30 of a 150 tank. Buoyancy's all all negative -1>-10 to start with. Since the -1 is all that counts you can off load perhaps 4# from using al80's. If you go to a BPW you wont need much lead at all.

I normally use lp95's a bit short but I am 6' and 260# there is a drastic difference In the amount of air In a lp95 filled to 3k. (108) AND A AL80 AT 77.
I suspect carrying another al40 is not the thing for you to do at your experience level.

One other thing ..... Do you know what your sac is. If it is bad it should improve in time and ease the problem.

 

[prunefoot]

I have one of those 149's. They are great tanks.. heavy, but you should be able to stay down a while..

I am liking those, just very expensive! If I get one, I will need two because most dive charters are two tanks... so lots of money haha.

 

[prunefoot]

The other question with steel tanks is HIgh Pressure or Low Pressure. I am not going to get into pros and cons of either as it has been debated adinenitum here.

You will probably never keep up with your wife and daughter. Women generally use less gas than men. The more you dive the better your air use will become if you work at being a good diver.

Most travel destinations have AL 80's as the rental tanks. A few have AL100 but they are not usually filled to 3000psi not the 3300psi to get their full fill. A very few operators have steel tanks.

Large steel tanks are fine for local diving if you drive to your destination but if you are going on vacation where you have to fly taking your own tanks is not feasible. For travel, Hoovers are looking at going to sidemount to have twice as much gas available for each dive. You would have to rent one or two extras AL80 tanks for a Two Tank Dive charter and have a Sidemount BC and an extra reg set.

I'm thinking high pressure due to size...
I agree, I don't think I could keep up with them. I just hate having them surface because of me. My 11 year old daughter is fearless and a fish, but my wife is still a little timid, so I won't leave them below. Thank God my had a very patient instructor because she freaked out having to do the mask removals on her check dive and he took extra time to get her through. It didn't help that they were in the jetties at tide change with current, low vis, and freaking jellyfish everywhere. I went with them to watch and take some photo/video of their training, and found myself swatting jellyfish away from them so they could focus. I eventually had the instructor take her down solo, so she wouldn't be distracted about worrying about our daughter. He held her BCD so she wouldn't drift in the current and she did her skills. I bought him a case of yuengling for his patience. She was still nervous and it takes her a while to descend and equalize on the first dive. Which was the Simpson wreck off PCB. It is prefect because it is clear water and around 20'. After the second day of diving, on her 4th boat dive, she was dong much better.

We will probably do most of our diving for the next few years from a great shop in PCB that did all of our training, and we drive there. The only travel diving I see in the future is catching inexpensive trips to Cozumel. For that, I only see taking my BCD, since I'm a big dude and it fits me.

I'm liking the way the sidemount sounds.

 

[prunefoot]

Even I am a smaller diver, I fell in love with large tank, HP130 to be particular. It is not so long like HP120, almost double the gas of AL80. I have been using HP100, which is good, if I have to do it again, I will get HP130

I noticed that too. It's like the 120 is long, the 130 and 149 are shorter, but wider. I'm liking the 130s, but hell, why not 149s? Like they say... go big or go home! haha

 

[prunefoot]

I have one of those 149's. They are great tanks.. heavy, but you should be able to stay down a while..

That's what I'm wanting. It costs me a ton for the 3 of us (and more when my youngest is old enough) so I want as much dive time as possible!

 

[prunefoot]

I'm also a larger diver... 6'6"... and about 350lbs (Ex-division I football linemen).

When I look for a possible dive operation to go with I will almost never dive with a shop that does not offer 100 cu/ft tanks. With very few exceptions I've always been able to find a shop in each city that I'm diving in that has them.

When traveling I think you'll be able to find 100's often (my experience is limited to Florida, Caribbean, and Mexico). There are a few shops that even use HP120's in Cozumel.

I've thought about this a lot and the best solutions I've come up with are: 1) diving side mount 2) Carrying a stage bottle (40 cu/ft or even another 80 cu/ft). Side mount would be nice because everyone offers 80's... and with 2 of them I could match the lowest SAC rates. With a stage bottle I could use it as needed, leaving it behind for dives that don't require it, and I wouldn't need a new bcd.

We sound very similar... like I said I'm 6'4" and float between 320 and 340. Due to years of gym and martial arts I have a muscular build.... with some padding around the middle haha.

I have gotten to know the guys at the PCB shop that trained all 3 of us, so I will probably sticking with them for all dives in that area. I'll take your advice on checking around for trips where we fly.

For now, our diving will be PCB and Cozumel, so knowing larger tanks are available is great.

I like the side mount option, I need to research it more.

Just as a note of interest, I purchased a small pony bail out rig as a backup. It was a 6cf bottle and, when I tested it on my last dive, I got 13 breaths between 50 and 60 feet.
https://www.amazon.com/gp/product/B01BKPTEGE/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

 

[prunefoot]

I'm in the same boat. 6'4" and 3 bills. I use HP133s. Like others have said women seem to use far less air. I've really watched my breathing rates both in and out plus I do my best to not use any extra energy/task load. Both help with my gas intake but still I'll surface with around 300-500 psi while my wife still has 1000+ psi in her tanks(HP100s).

If you're going to purchase tanks I'd definitely say go with 130s and if you're traveling and unable to take tanks with you find a shop in the area you plan on diving that has at least HP100s you can rent. It would help especially if you're starting a dive in the 3500 psi ball park higher volume tank and they're using AL80s starting off around 3000.

Thanks for the info. I'm thinking about a pair of 130s since most inshore charters are 2 tanks. I can never seem to catch an offshore 3 tank charter, but buying 3 tanks would break me right now haha.

 

[NAM001]

Something else to think about. Most people use al80's because they are the most available tank there is. when you dive at home in FW you know before you board that plane how much weight you are going to need when you get to coz. its 1# for every 30-40# of you fully rigged. Start changing tanks and set suits and it gets more difficult to get the weighting close to get the max for you diving buck. Here is an example. I dive with a lp95 in fw with a shorty and I need no weights. I goto coz wit no suit and I need 16# and 21 if I wear the shorty with their al80 tank. scaled out rigged I am about 330# that should take 8-11# with my same gear. now a al tank 4# more buoyant and no suit should be a wash but it takes 14-16# of lead.With my same FW gear on a boat in coz like waters I put on 8# and I am good. That works out to 1# for every 40 for me.

 

[prunefoot]

I am 6'4 250+ and like lp 120's. If you can get them overfilled you can get almost 180 cft out of them. OMS made some lp 131's and they are awesome overfilled. Pat Green, Rob or Edd all will give you good fills in the PCB / Panhandle area. Rob's fill shop is 24/7 self service and cheaper than anyone else in the area at $0.10/cft for Nitrox.

Overfilled... interesting. So far, all of my experience has been with Pat's shop (PCDiving) and it has been great. He has a great crew with great instructors. I'll give a shout out to Chris, who was my OW, AOW, and Nitrox instructor, and Travis, who instructed my wife and daughter for their OW cert. He had a hard time with my wife stressing out, but he was patient and got her through it. We dove with them all week. Attached is a pic of the boat crew, a spearfisher named Ken, and our 3 person group.

Edit: which shop is Rob's?