Question How to tell what type of diving each BCD is/was designed for?

[Dann-Oh]

I hear a lot about make sure you choose the right BCD for the type of diving you do. But how does one find that kind of info? Take me for example, I dive off the coast of Southern California (ocean water temps from 50-70°F (10-21°C)), I dive both wet and dry suit (when dry I use 300g socks, pants, socks). I am currently diving within recreational limits but do have desire to get into decompression diving not necessarily deeper diving (yet). I sidemount both Faber LP50 and PST LP72 sized tanks. I am currently using a Hollis SMS75 but my instructors are using the xdeep stealth 2.0 tec. The rest of my dive team uses the xdeep 2.0 tec as well.

Is the SMS75 the right BCD for my use case?

What I do not like about the SMS75 is not having a butt dump. I have a hard time finding the1 end of the pull cord for the shoulder dump valve on my SMS75. I'm not looking forward to the purchase of an additional BCD but I will get it if the xdeep is the right tool for the job.

 

[tbone1004]

So the SMS75 was designed for Florida cave diving, specifically the Edd Sorenson style of sidemount diving and took all of the modifications he was doing to the SMS100 and had it come stock. That style is extremely different to that of most of the xDeep crowd in terms of tank rigging where most of them don't use butt plates at all and even Edd has changed his style of diving in the last few years due to rebreather use. The top dump was originally known as the Sorenson Swap if you were sidemount diving 15 years ago, so that's definitely something attributed to him and while most of us love it and many have done that modification to their xDeeps. Of note I have never had any love for the SMS100/75 or that style of rig and for my big steel tanks I use a Nomad XT, so take that as a grain of salt as we go down this path.

I've weirdly said it a lot more in the last 2 months than the last few years but the subject seems to be coming up more and more often, but unless you really have to use steel tanks for the capacity, I really don't recommend most people use them for sidemount diving and instead recommend they weight themselves with just the rig and use AL80's only. This is what most of the guys in Europe are doing and it all stems from how the tanks attach to the rigs and frankly just how much easier AL80's are to dive in a sidemount configuration compared to steel.

Assuming your LP50's are cave filled and your 72's are not, you're diving within AL80 capacity anyway for shore/boat diving in SoCal you really won't be pressed for that much more gas use. LP72's are pretty floaty and LP50's aren't that heavy either so those aren't a big change vs AL80's but anything bigger is going to be a bit of a problem with an xDeep.

If you are comfortable with the equipment you have, then stay with it, but if you are unsure and/or ready to make a switch I would say dump the LP72's and the SMS75 and get something that is more inline with what your team is using.

 

[Edward3c]

I dive with a buddy who’s changed the pull cord end with a rubber duck, difficult to mistake. Use and set up your kit so it works for you. Don’t buy equipment just because your instructor uses it.

 

[Dann-Oh]

I've weirdly said it a lot more in the last 2 months than the last few years but the subject seems to be coming up more and more often, but unless you really have to use steel tanks for the capacity, I really don't recommend most people use them for sidemount diving and instead recommend they weight themselves with just the rig and use AL80's only. This is what most of the guys in Europe are doing and it all stems from how the tanks attach to the rigs and frankly just how much easier AL80's are to dive in a sidemount configuration compared to steel.

Steel tanks are so much easier to use for me, I need so much more weight when using an AL80 vs LP72.

Assuming your LP50's are cave filled and your 72's are not, you're diving within AL80 capacity anyway for shore/boat diving in SoCal you really won't be pressed for that much more gas use. LP72's are pretty floaty and LP50's aren't that heavy either so those aren't a big change vs AL80's but anything bigger is going to be a bit of a problem with an xDeep.

Im not too sure what you mean by "cave filled". Both my LP50s and LP72 are "+" marked so I can fill the LP50s to 2600psi (well technically 2650 but our fill station only goes to the 100's digit, so I round down) and the LP72s to 2400psi.

If you are comfortable with the equipment you have, then stay with it, but if you are unsure and/or ready to make a switch I would say dump the LP72's and the SMS75 and get something that is more inline with what your team is using.

Yeah that's what I'm thinking. I have just gotten comfortable with my kit so I think I'll stay with it for now.

 

[tbone1004]

@Dann-Oh you need 8-10lbs more with AL80's but in the spine pouches on rigs like the Stealth it is a net benefit since it's that much easier to deal with AL80's than steel tanks. The SMS75 is not particularly well suited for AL80's because it wasn't designed for it but the other rigs were designed specifically for AL80's so it's best to stick with that.

Cave fill is 3600psi in the LP50's or about 3000 in the LP72's. If you're only filling to legal pressure your rig weight:cf is actually higher than it is with AL80's

 

[SlugLife]

unless you really have to use steel tanks for the capacity, I really don't recommend most people use them for sidemount diving and instead recommend they weight themselves with just the rig and use AL80's only.

I recently acquired some steel-tanks after loads of side-mount divers recommending them. The advantages didn't seem to match the "hype." I love the extra capacity, but otherwise, it doesn't impact my diving itself, and mostly means I have to change my weights from when I dive AL 80s. Perhaps if I was dry-suit diving, they would be useful there.

Steel tanks are so much easier to use for me, I need so much more weight when using an AL80 vs LP72.

That might be the issue for me. I use about 5lbs when diving with AL80s.

I dive with a buddy who’s changed the pull cord end with a rubber duck, difficult to mistake. Use and set up your kit so it works for you. Don’t buy equipment just because your instructor uses it.

Funny and brilliant. I might have to do something similar. I sometimes have a hard time finding mine by feel, and then being sure I grabbed the right thing. ("Is that it? Nope, that's my butt." j/k)

 

[Cheizz]

More on different sidemount BC designs and a thorough comparison review of the xDeep Stealth 2.0 Tec and Hollis Katana 2: XDeep Stealth Tec vs Hollis Katana 2 | Reviewed

 

[Dann-Oh]

Perhaps if I was dry-suit diving, they would be useful there.

Yeah that's exactly why I like steel tanks. For example, with my stainless steel backplate and wing setup, I can dive 3 different tanks: LP72, HP100, and Al63 (I use the Al63 in pool sessions with OW students). My weighting in my drysuit for single back gas is: Hp100 - 14lbs, LP72 - 16lbs, Al63 - 20lbs.

For my sms74 it is: 14lbs for both LP72s and LP50s.

My SMS75 maxes out at 18lbs of lead, I don't think I could dive drysuit with 2x Al80. I might do the 2xAl63 just for fun but I'd rather just do the 2x Lp72

 

[Robert H. Diver]

More on different sidemount BC designs and a thorough comparison review of the xDeep Stealth 2.0 Tec and Hollis Katana 2: XDeep Stealth Tec vs Hollis Katana 2 | Reviewed

I didn’t like this review, found it to be a bit biased in my opinion. He said some features of the K2 were unsafe? Which I found to be a ridiculous statement.

 

[Cheizz]

I didn’t like this review, found it to be a bit biased in my opinion. He said some features of the K2 were unsafe? Which I found to be a ridiculous statement.

Yeah I referenced it primarily for the bit about different BCD designs.