which rig? (I am about to buy an SMS75 is this a mistake)

[Teknadv3x]

The Texasguy
lives in paradise and he still is looking for a better mouse trap.

 

[stretchthepenn]

Nope, the amount of lukewarm reviews has turned me away from it to LS. After SMS100 I was careful not to buy another Hollis without much research.

I originally bought a Hollis 100D; it was OK. I then bought a Hollis 75, was much happier with it, and retired the 100. Now that I've started my Tec training, though, I got the Edd Mods done to the 100, which essentially turned it into a double-bladder version of the 75; I like it plenty.

 

[Texasguy]

My SMS100 was also modified by Edd. Still, I feel like the bladder allowed too much air to the shoulders when well expanded by air (Edds mod then stretches out the bladder when full, allowing more air to go where its extra bungee-ed still - to the shoulders). That is a common problem with Hollis, in my own personal view. If you look at the bladder shape, they do lately tend to minimize air in the shoulders area after SMS100 model. And I hear it is not enough, too much buoyancy in the top section needing extra weights.

Looking at the British system, I think they are on a better path, as their bladders are concentrating air in the hip regions, giving lift where it is needed, not around the lungs, where you have that natural lift by just breathing. I am not saying there should not be any bladder on top of the lungs, just much more minimized.

There are mine observations. I am just against of donning extra shoulder weights to offset the air in the wing. You would say, well, then don't put so much air, but the hips then sink. To bring the hips to the level makes shoulders too light. That is the chicken-egg game with Hollis.

 

[Bigeclipse]

My SMS100 was also modified by Edd. Still, I feel like the bladder allowed too much air to the shoulders when well expanded by air (Edds mod then stretches out the bladder when full, allowing more air to go where its extra bungee-ed still - to the shoulders). That is a common problem with Hollis, in my own personal view. If you look at the bladder shape, they do lately tend to minimize air in the shoulders area after SMS100 model. And I hear it is not enough, too much buoyancy in the top section needing extra weights.

Looking at the British system, I think they are on a better path, as their bladders are concentrating air in the hip regions, giving lift where it is needed, not around the lungs, where you have that natural lift by just breathing. I am not saying there should not be any bladder on top of the lungs, just much more minimized.

There are mine observations. I am just against of donning extra shoulder weights to offset the air in the wing. You would say, well, then don't put so much air, but the hips then sink. To bring the hips to the level makes shoulders too light. That is the chicken-egg game with Hollis.

I purchased the sms75 and will add comments about it but from what I have read, the shape of the wing is just fine and really does not allow too much air near the shoulders, assuming you are properly weighted and trimmed. I must add that I drysuit dove so do not use the bladder much for buoyancy but rather the drysuit itself.

 

[stretchthepenn]

I must add that I drysuit dove so do not use the bladder much for buoyancy but rather the drysuit itself.

At the straight-up recreational level, controlling your buoyancy with the drysuit is a workable solution, and truth be told, I think it's a useful skill to have. If you intend to continue with your training, though, I suggest learning to control your buoyancy with your BCD and using just enough gas to inflate your drysuit.

The idea is that controlling your depth with a BCD's smaller, more-contained bubble and precisely-controllable vents is easier and more efficient--especially when you're ascending and need to maintain consistent depth at a decompression stop--than controlling your depth with a drysuit's very large bubble and single outlet.

You'll have to manage two separate bladders at once, but the task-loading shouldn't be that onerous, and you'll learn a required skill for more-advanced classes.

 

[Texasguy]

the shape of the wing is just fine and really does not allow too much air near the shoulders, assuming you are properly weighted and trimmed

I think the missing information here is not the initial weight and trim but how it affects throughout the dive.

Say, those who cave dive, they bring rather a sizable chunk of air back. Thus, they might not feel the weight shift fully at the end of the dive. Basically, they never get to that stage where tanks are most light bottomed at the end of the dive.

Yet those who dive recreationally may find themselves with around or less than 500psi in each tank, close to that extreme shift in weight in the hip area (and the trim experience leading to these low psi, not necessary starting only when the extreme low psi is reached).

This brings a noticeable problem to some divers (depending on air reserve brought back).

Say, as you put it, at the start of the dive you are well weighted and in good trim. At that stage of the dive the tanks are the heaviest, you need much air in the wing to bring up the hips. But, since that air also brings up shoulders, you put more weight there. All great, you are weighted and trimmed.

Then after, as tanks become lighter at the hip, you don't want to keep as much air compensation in the wing, you blow out some. And then some, and then some. This brings you with little air in the wing, you don't need much for hips at that point, and it almost none there in the shoulders now. But you still have and all this hard weight on your shoulders to compensate for that prior air when wing was well expanded and you were in trim. Yet now your shoulders start to sink. The only way to bring up shoulders is to put more air in the wing but that makes your hips much lighter, and you are still a bit head heavy.

Therefore, my personal preference to put as little weight to shoulders as possible to remain better in trim at the end of the dive. You might be trimmed and well weighted at the start of the dive but deficiencies in wing design can make you fight the trim at the end of the dive. Again, if you cave dive, perhaps you do not experience the shift that much.

Thus, when I was diving SMS100, my strategy was to start a dive where I was trimmed with my hands extended ahead of me, by bringing by hands up ahead, this would add more weight to my shoulders vs hips, in a way of controlling a pivot point. As the dive progressed, I'd bend my hands at the elbow more, then bringing them in and then under. Not optimal but a trick.

 

[Bigeclipse]

At the straight-up recreational level, controlling your buoyancy with the drysuit is a workable solution, and truth be told, I think it's a useful skill to have. If you intend to continue with your training, though, I suggest learning to control your buoyancy with your BCD and using just enough gas to inflate your drysuit.

The idea is that controlling your depth with a BCD's smaller, more-contained bubble and precisely-controllable vents is easier and more efficient--especially when you're ascending and need to maintain consistent depth at a decompression stop--than controlling your depth with a drysuit's very large bubble and single outlet.

You'll have to manage two separate bladders at once, but the task-loading shouldn't be that onerous, and you'll learn a required skill for more-advanced classes.

I can control my buoyancy with my wing as well as my drysuit. I do find it easier to just use my drysuit and I have practiced doing "pretend" deco stops. What I mean by this is I often make dives in the 100-130ft range at our lake and just for added safety will make a 5+min safety stop at 10ft at the end of the dive. I have never had an issue maintaining proper trim/buoyancy even when there was not a safety line to watch if I were sinking and I was just using my dive computer to monitor depth. I fluctuate maybe a foot or 2 but no more. I will definitely take your advice though and train more using both my wing and drysuit. Just enough in the suit to take the squeeze off and use the wing.

 

[Bigeclipse]

I think the missing information here is not the initial weight and trim but how it affects throughout the dive.

Say, those who cave dive, they bring rather a sizable chunk of air back. Thus, they might not feel the weight shift fully at the end of the dive. Basically, they never get to that stage where tanks are most light bottomed at the end of the dive.

Yet those who dive recreationally may find themselves with around or less than 500psi in each tank, close to that extreme shift in weight in the hip area (and the trim experience leading to these low psi, not necessary starting only when the extreme low psi is reached).

This brings a noticeable problem to some divers (depending on air reserve brought back).

Say, as you put it, at the start of the dive you are well weighted and in good trim. At that stage of the dive the tanks are the heaviest, you need much air in the wing to bring up the hips. But, since that air also brings up shoulders, you put more weight there. All great, you are weighted and trimmed.

Then after, as tanks become lighter at the hip, you don't want to keep as much air compensation in the wing, you blow out some. And then some, and then some. This brings you with little air in the wing, you don't need much for hips at that point, and it almost none there in the shoulders now. But you still have and all this hard weight on your shoulders to compensate for that prior air when wing was well expanded and you were in trim. Yet now your shoulders start to sink. The only way to bring up shoulders is to put more air in the wing but that makes your hips much lighter, and you are still a bit head heavy.

Therefore, my personal preference to put as little weight to shoulders as possible to remain better in trim at the end of the dive. You might be trimmed and well weighted at the start of the dive but deficiencies in wing design can make you fight the trim at the end of the dive. Again, if you cave dive, perhaps you do not experience the shift that much.

Thus, when I was diving SMS100, my strategy was to start a dive where I was trimmed with my hands extended ahead of me, by bringing by hands up ahead, this would add more weight to my shoulders vs hips, in a way of controlling a pivot point. As the dive progressed, I'd bend my hands at the elbow more, then bringing them in and then under. Not optimal but a trick.

ah ok I get it. I have heard that the sms75 does not have the issues as the sms100 but maybe still not perfect it sounds.

 

[tbone1004]

@Bigeclipse drysuit=comfort, wing=buoyancy. Annoyingly many teach drysuits as buoyancy since you don't actually need a wing with most single tank diving, especially when there is no suit compression. Your lungs can easily shift 6lbs of buoyancy which is the gas capacity of an AL80. If the drysuit takes over anything on top of that, it's a cake walk. Once you get into diving with multiple tanks that no longer holds true and you need to use the suit for what it's designed for and then the wing to do what it is designed for.

 

[Bigeclipse]

@Bigeclipse drysuit=comfort, wing=buoyancy. Annoyingly many teach drysuits as buoyancy since you don't actually need a wing with most single tank diving, especially when there is no suit compression. Your lungs can easily shift 6lbs of buoyancy which is the gas capacity of an AL80. If the drysuit takes over anything on top of that, it's a cake walk. Once you get into diving with multiple tanks that no longer holds true and you need to use the suit for what it's designed for and then the wing to do what it is designed for.

I will certainly practice with both but it’s odd because I’ve made about 20 dives with manifolded back mount doubles. I rarely use the wing for Buoyancy while driving those I definitely used the wing when I was on the surface abd was just floating around.