Too much of a Good Thing

I have developed (of all things) a SEVERE head-down trim condition in my single-tank cavern rig while running shallow…

Givens:
95 steel with H-valve
Stainless steel b/p
DR Venture Cell
Wreck Canister, right belt mount
3# lead in Clipper pocket, left belt mount (to counter roll from battery)

I was diving a VERY old 3/3 combo, and trim was a tad head down but acceptable; now diving a 5mil one-piece, and find it difficult to NOT assume dancing on head posture when 20’ or shallower…also, unstable in roll axis (wanting to invert until past 20’)

Suspicions:
The new suit has moved the CB down towards legs…
The small size of the cell prevents the CB from moving “up” relative to CG of tank until sufficient gas is input…
Shorter tank moves CG forward towards shoulders, acerbated by s/s BP (I noted LESS problems with an AL80)…

Possible fixes:
Ally b/p (moves CG aft)…this would unfortunately mean I had to carry more lead…
Traditional wing (Trek is next size up)…this would move CB aft, but in a single tank, I fear the dreaded “Taco shell” config…
Ankle weights…UGH!

Do any of the fine-trimmed Readers here have other ideas/comments?

Thanks!
Norm

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Originally Posted by normblitch

Do any of the fine-trimmed Readers here have other ideas/comments?

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Sounds like you've got most of the ideas covered. You might consider adding a neoprene vest or vest+hood combination to any of the other ideas which might shift CB higher while also adding warmth to the toso area. A little violence with a pair of shears on your old combo upper might provide something suitable at little or no cost (shearing the arms short/loose especially to keep mobility).

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Originally Posted by Gary

Quote:

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Originally Posted by normblitch

Do any of the fine-trimmed Readers here have other ideas/comments?

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Sounds like you've got most of the ideas covered. You might consider adding a neoprene vest or vest+hood combination to any of the other ideas which might shift CB higher while also adding warmth to the toso area. A little violence with a pair of shears on your old combo upper might provide something suitable at little or no cost (shearing the arms short/loose especially to keep mobility).

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Good Idea! Will shop for vest soonest...Thanks!!

(BTW, steelie is ALREADY as low as it can go on the b/p)

Norm

Norm,
-do you use jetfins (they are heavier)?
-you may try to restrict lower part of aircell with bands
- there are special small trim weight pockets that you can place on shoulder straps or onto tank upper (lower in your case) camband
- wing won't do a "taco" if you link it to the plate using existing or sewn tabs (steel links or cave line may be used)
- did you eat carrots before dive? Then make 3-4 holes in crotch area :-)
How was your pony bottle plonge, did take any nice pics last weekend?

If you're not using Jetfins (or equivalent), try those. They're much heavier than crappy plastic fins and they form a nice counterweight when in a horizontal position.

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Originally Posted by ARY

Norm,
-do you use jetfins (they are heavier)?
-you may try to restrict lower part of aircell with bands
- there are special small trim weight pockets that you can place on shoulder straps or onto tank upper (lower in your case) camband
- wing won't do a "taco" if you link it to the plate using existing or sewn tabs (steel links or cave line may be used)
- did you eat carrots before dive? Then make 3-4 holes in crotch area :-)
How was your pony bottle plonge, did take any nice pics last weekend?

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Ary,

I'm using Lamar's DiveRites...they are sinkers, but don't know how they compare to Jets...Bev has a pair, and that may be something to try...also, I still haven't tried the Fara II's yet...AFAIR, they WERE sinkers!!

trim in Cam band is food for thought...

"Capturing" wing on b/p...like Trek mods for sidemount??

Carrots, NO...Breakfast Burrito of Death a possibility...beware of brown bubbles...<g>

Survived pony OK under Tom's watchful eye...
seen at http://www.pbase.com/eanx/ginnie4305 ...

Norm

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Originally Posted by DRE

If you're not using Jetfins (or equivalent), try those. They're much heavier than crappy plastic fins and they form a nice counterweight when in a horizontal position.

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Dre,

Heavier fins ARE a more attractive option than ankle weights...more Science Projects for Ginnie Saturday...Thanks!

Norm

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Now THIS sounds elegant...I'm assuming that the crotch strap is then snugged up in reaction to avoid ride-up?

Norm

Quote:

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Originally Posted by normblitch

Quote:

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Now THIS sounds elegant...I'm assuming that the crotch strap is then snugged up in reaction to avoid ride-up?

Norm

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I personally would not recommend this - once the harness is properly adjusted it should be left alone. Shoulder straps that are sliding all over the place are a CF.
One other question I have for you is how much do you arch your back? When you keep your back straight, it'll usually push your head down; however, if you arch your back it'll push your head. While it may seem somewhat uncomfortable at first, your muscles will get used to it.

Quote:

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Originally Posted by DRE

Quote:

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Originally Posted by normblitch

Quote:

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Now THIS sounds elegant...I'm assuming that the crotch strap is then snugged up in reaction to avoid ride-up?

Norm

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I personally would not recommend this - once the harness is properly adjusted it should be left alone. Shoulder straps that are sliding all over the place are a CF.
One other question I have for you is how much do you arch your back? When you keep your back straight, it'll usually push your head down; however, if you arch your back it'll push your head. While it may seem somewhat uncomfortable at first, your muscles will get used to it.

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Dre,

while I'm SURE that a b/p could be adjusted into the seemingly envogue lowrider look seen (sadly) on so many OW nuggets today, I think it MIGHT be possible that mine is, in fact, TOO high...If I try to tilt my head back to full "up" range of motion, I hit the limit switch formed by the valves, et al...

???

Norm

Quote:

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Ditto. Where the theory of super tight backplates came from is a mystery. Make it comfortable! If it fits like a nice shirt, not too snug, not too baggy, then you will enjoy wearing it more. The more you enjoy wearing it, the more you dive. The more you dive, the happier you will be. The happier you are, the more you dive.

Repeat as necessary.

Also, crotch straps suck unless you are scootering.

Get your harness to fit and go diving!

Cheers,
Jamie

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Originally Posted by normblitch

Quote:

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Originally Posted by DRE

Quote:

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Originally Posted by normblitch

Quote:

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

---

Now THIS sounds elegant...I'm assuming that the crotch strap is then snugged up in reaction to avoid ride-up?

Norm

---

I personally would not recommend this - once the harness is properly adjusted it should be left alone. Shoulder straps that are sliding all over the place are a CF.
One other question I have for you is how much do you arch your back? When you keep your back straight, it'll usually push your head down; however, if you arch your back it'll push your head. While it may seem somewhat uncomfortable at first, your muscles will get used to it.

---

Dre,

while I'm SURE that a b/p could be adjusted into the seemingly envogue lowrider look seen (sadly) on so many OW nuggets today, I think it MIGHT be possible that mine is, in fact, TOO high...If I try to tilt my head back to full "up" range of motion, I hit the limit switch formed by the valves, et al...

???

Norm

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Norm,

I can fit my fist in between my body and shoulder straps (if that gives you an indication as to how tight I have mine. The top of the plate reaches my second vertebra; crotch strap is adjusted so it is snug but doesn't pull the waist strap down (the waist strap does not angle down from the plate as it comes around).
With a single tank, I also can hit my first stage with the back of my head. With doubles I can just hit the crossbar knob. I can easily reach my vales both in the single and double tank setup.
For a detailed explanation with pix: http://dir-diver.com/en/equipment/ba...djustment.html

Hope this helps,
David

In the beginning I was wearing my backplate too high, creating all sorts of uncomfortable issues (not the least of which was difficulty reaching across my chest due to the tightness of my shoulder straps. I tried many fixits, including weights, heavier fins, etc etc. Finally I just started over from scratch, re wove my backplate (the longer shoulder straps were actually an accident) and viola, my trim returned to normal. And now I can easily reach across my chest. Valve shutdown used to be difficult until I realized my crotch strap didn't have to make me sing soprano in order to keep my tanks on my back. Now I can move my tanks up or down about 3" without having to undo it. Arching my back keeps them in place without really having to think about it. This is with a doubles setup, you may find this solution doesn't suit a single setup as well, but hey, it's free, and what do you have to lose but your floating feet? :lol:

Quote:

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Originally Posted by normblitch

I have developed (of all things) a SEVERE head-down trim condition in my single-tank cavern rig while running shallow…

Givens:
95 steel with H-valve
Stainless steel b/p
DR Venture Cell
Wreck Canister, right belt mount
3# lead in Clipper pocket, left belt mount (to counter roll from battery)

I was diving a VERY old 3/3 combo, and trim was a tad head down but acceptable; now diving a 5mil one-piece, and find it difficult to NOT assume dancing on head posture when 20’ or shallower…also, unstable in roll axis (wanting to invert until past 20’)

Suspicions:
The new suit has moved the CB down towards legs…
The small size of the cell prevents the CB from moving “up” relative to CG of tank until sufficient gas is input…
Shorter tank moves CG forward towards shoulders, acerbated by s/s BP (I noted LESS problems with an AL80)…

Possible fixes:
Ally b/p (moves CG aft)…this would unfortunately mean I had to carry more lead…
Traditional wing (Trek is next size up)…this would move CB aft, but in a single tank, I fear the dreaded “Taco shell” config…
Ankle weights…UGH!

Do any of the fine-trimmed Readers here have other ideas/comments?

Thanks!
Norm

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Upon reading your post my 1st thoughts would be to make sure you have your tank as low as it can go....move your weight lower (maybe a dreaded wt belt)...A change of fins will make minimal difference - you've got something going on, and a good instructor should be able to fix it if you get in the water with them. Don't worry, you will be horizontal again. Oh, I almost forgot - the AL BP idea was a good one too. Oh yeah, I forgot again, the Transpac may fix it too.

With all of the talk concentrating on the shoulder and crotch straps, is your waist strap at your waist? This puts the whole rig at the "right place", and the shoulder straps just kind of hold it in place. No bondage setup with sternum straps, crotch straps, etc. Just nice and simple. I used an AUL plate with a single tank adaptor and trek wing (snugged in tight with the shock cord retractors) and it worked fine for AL80's in salt water.

The other solution is to get your steel 95 an "evil twin" and double up. If it's beyond the limits of your current training, start drifting towards the next class or two that will get you in the right gear. It's much more fun to dive doubles - no fear of hitting thirds while in the daylight zones of most caves.

Best of Luck,

Mark

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Originally Posted by JDR

Quote:

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Originally Posted by divindoubles

As simple as it sounds, I corrected the same problem by letting my shoulder straps out a couple of inches, which drops the whole rig down toward the (picture forrest gump here ;o) buttocks. No extra weight, no silly golf swing fixes, just about an inch of back plate at the cleft of the nates.

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Ditto. Where the theory of super tight backplates came from is a mystery. Make it comfortable! If it fits like a nice shirt, not too snug, not too baggy, then you will enjoy wearing it more. The more you enjoy wearing it, the more you dive. The more you dive, the happier you will be. The happier you are, the more you dive.

Repeat as necessary.

Also, crotch straps suck unless you are scootering.

Get your harness to fit and go diving!

Cheers,
Jamie

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Jamie (and others),

I let my shoulders out 2" each this AM...will try Saturday and report back...if any of y'all see a pair or DR or Fara II's air-kicking in the Bowl @ Ginnie tomorrow, you will know this didn't work...<g>

Norm

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Norm,

I can fit my fist in between my body and shoulder straps (if that gives you an indication as to how tight I have mine. The top of the plate reaches my second vertebra; crotch strap is adjusted so it is snug but doesn't pull the waist strap down (the waist strap does not angle down from the plate as it comes around).
With a single tank, I also can hit my first stage with the back of my head. With doubles I can just hit the crossbar knob. I can easily reach my vales both in the single and double tank setup.
For a detailed explanation with pix: http://dir-diver.com/en/equipment/ba...djustment.html

Hope this helps,
David

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David,

I was hunting for that link for comparison; Thanks!

Per the photos, my plate DID seen a scosh to high...I'll see how well 2" more in the shoulders works out...lights and rings sure seem a better fit.

Norm[/quote]

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Originally Posted by mfascuba

With all of the talk concentrating on the shoulder and crotch straps, is your waist strap at your waist? This puts the whole rig at the "right place", and the shoulder straps just kind of hold it in place. No bondage setup with sternum straps, crotch straps, etc. Just nice and simple. I used an AUL plate with a single tank adaptor and trek wing (snugged in tight with the shock cord retractors) and it worked fine for AL80's in salt water.

The other solution is to get your steel 95 an "evil twin" and double up. If it's beyond the limits of your current training, start drifting towards the next class or two that will get you in the right gear. It's much more fun to dive doubles - no fear of hitting thirds while in the daylight zones of most caves.

Best of Luck,

Mark

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Mark,

The waist strap SHOULD have been a tell-tale sign...it WAS fitting more like a breath band on a polygraph than where it usually is seen riding (slightly above belt-line)

Dub 95's?, nah, when and IF I return to doubles I'll be lucky if I can do 85's....ashamed to be seen in a pair of 72's....<g>

Many Thanks!
Norm