Sink-y feet

[Wardy_uk]

Come and sit in on the morning dry run if you can or just come and say hi.

Sent from my SM-G920F using Tapatalk

Wont be able to sit in on the dry run - but will definitely try and find you to say Hi...

[Ian_6301]

first off a badly fitting suit with too much spare capacity will always be a PITA to dive when learning as will a wing / stab jacket that is too big, both will have you rolling all over the place if you are overweighted and have gas swooshing about. get a better fitting suit and do a proper weight check.

TBH there is no magic bullet and each different kit configuration will behave differently. The DIR twinset setup where everyone uses the same configuration means that what works for one pretty well works for all and is a benefit of the standardised kit config and way of diving but it doesn't mean that you necessarily need to adopt the same body position if you are diving a different kit configuration.

you can do so much with core muscle strength and arching you back etc but at the end of the day it's all about moments about your CofG. find yourself rolling to the right all the time? move mass to the left, constantly head up? shift weight up, or add a little air to your feet or shove your arms out in front or bend your knees and bring your feet nearer your CofG. head down? pull your arms in, slide your cylinder down, push your feet out, etc

kit wise you can shift stuff about to shift that CofG or change for heavier or lighter fins or use (shudder) ankle weights if you really have to (though I don't believe I've ever met anyone who REALLY needs them). Think about the forces of bits of kit and where those forces are acting, little teaks can have big benefits in comfort and stability. I used to put an old torch canister containing a PLB in the bottom of my unit as the half kilo or so of buoyancy helped off set any residual small gas bubble in over the shoulder lungs. clipping off a heavy torch on deco on an upper chest ring instead of a hip ring will put your head down. clipping a sidemounted stage diagonally across your chest can stop the weight rolling you over.

I hate to say it but the best solution to this problem is thought, practice and time. And the more time you spend underwater actively thinking about how you are interacting with the environment and playing with your buoyancy and trim, the better your buoyancy and trim will be. long deco stops normally allow plenty of time for thinking about tweaks but any relatively long periods (and i'm not thinking two or three minutes but 20 or 30 or more) hovering in shallow water and consciously adjusting your body position (legs bent to bring your CofG forward, out to move it back, same with the arms), moving bits of kit about or shuffling sips of gas in and out of your feet and wing will do.

in summary get rid of any excess weight first then get in the water and spend lots of time playing with your kit configuration, adjusting your body position and thinking about how those changes affect your trim and increase your ability to look fabulous.

Agree with all of your post, MikeF. Particularly agree with the bit about 20-30 mins deco. Try just staying still in formation for half an hour with a buddy or two. just hover, no fin kicks. Do it about 6" above the bottom and centred on an identifiable object (funny looking rock or something). That will soon flush out any issues.

The only thing that I'd sound a not of caution over is the bit in bold above.

If you are hog looping, DO NOT clip the stage off anywhere other than left hip/left shoulder* or you will risk trapping the long hose, which may cause irreparable damage to your buddy...

Equally if you use an Ali stage, it should only ever be about +/-1.5kg off neutral....

*yes, yes, I know you can go right hip/right shoulder and get away with it if you know what you're Doing It Chasey...

[MikeF]

what about brexit, scottish independence, youth of today, corbyn, international terrorism? oh and where the hell have the cheeky girls gone?

[Wardy_uk]

first off a badly fitting suit with too much spare capacity will always be a PITA to dive when learning as will a wing / stab jacket that is too big, both will have you rolling all over the place if you are overweighted and have gas swooshing about. get a better fitting suit and do a proper weight check.

TBH there is no magic bullet and each different kit configuration will behave differently. The DIR twinset setup where everyone uses the same configuration means that what works for one pretty well works for all and is a benefit of the standardised kit config and way of diving but it doesn't mean that you necessarily need to adopt the same body position if you are diving a different kit configuration.

you can do so much with core muscle strength and arching you back etc but at the end of the day it's all about moments about your CofG. find yourself rolling to the right all the time? move mass to the left, constantly head up? shift weight up, or add a little air to your feet or shove your arms out in front or bend your knees and bring your feet nearer your CofG. head down? pull your arms in, slide your cylinder down, push your feet out, etc

kit wise you can shift stuff about to shift that CofG or change for heavier or lighter fins or use (shudder) ankle weights if you really have to (though I don't believe I've ever met anyone who REALLY needs them). Think about the forces of bits of kit and where those forces are acting, little teaks can have big benefits in comfort and stability. I used to put an old torch canister containing a PLB in the bottom of my unit as the half kilo or so of buoyancy helped off set any residual small gas bubble in over the shoulder lungs. clipping off a heavy torch on deco on an upper chest ring instead of a hip ring will put your head down. clipping a sidemounted stage diagonally across your chest can stop the weight rolling you over.

I hate to say it but the best solution to this problem is thought, practice and time. And the more time you spend underwater actively thinking about how you are interacting with the environment and playing with your buoyancy and trim, the better your buoyancy and trim will be. long deco stops normally allow plenty of time for thinking about tweaks but any relatively long periods (and i'm not thinking two or three minutes but 20 or 30 or more) hovering in shallow water and consciously adjusting your body position (legs bent to bring your CofG forward, out to move it back, same with the arms), moving bits of kit about or shuffling sips of gas in and out of your feet and wing will do.

in summary get rid of any excess weight first then get in the water and spend lots of time playing with your kit configuration, adjusting your body position and thinking about how those changes affect your trim and increase your ability to look fabulous.

Pretty confident my weight's nailed - however the suit being too big is definitely a PITA... a MTM suit is on the shopping list, but not likely in the short term

ankle weights definitely wouldn't help me maybe I could strap one round my neck though?

[MikeF]

what you really need of course is to balance your stages on each side taking into account the molecular weight of the gas and the buoyancy characteristics of the cylinder (material, wall thickness, weight of valve, etc), before we even get into top of shoulder vs over the shoulder vs back mounted counterlungs, but as usual we are now getting waaay off piste for 'how do I stop my sinky feet?'

[WFO]

what you really need of course is to balance your stages on each side taking into account the molecular weight of the gas and the buoyancy characteristics of the cylinder (material, wall thickness, weight of valve, etc), before we even get into top of shoulder vs over the shoulder vs back mounted counterlungs, but as usual we are now getting waaay off piste for 'how do I stop my sinky feet?'

Both sinky feet/ one sinky arm and one sinky leg are different sides of the same subject...


I still haven't sussed it and so far I've ended up with using steels for trimix and ally for nitrox like mark does but it's still not perfect. Fair play to the gueeeeys who can manage one arm full of stages that must be negative as a barrel of bricks.

[Wardy_uk]

well, following some good advice on here, I went back and got my buoyancy and trim re-assessed yesterday - totally nailed it: Graded "Ninja" Black!

(Not quite GUE standards but in BSAC world, that's holding stops to + or - 30 cm for 2 mins each at numerous depths: including 30secs at 1m which is interesting... )

Quite chuffed - especially as the assessment dive was only my 20th OW dive

[Wardy_uk]

Come and sit in on the morning dry run if you can or just come and say hi.

Sent from my SM-G920F using Tapatalk

@Badger - afriad I missed you on Sun - how often do you run the exp days? Would like to have a go on one before *possibly* considering fundies later in the year...

[Tewdric]

Come down to Chepstow on Saturday then - I think there's still one place left!

[nigel hewitt]

To match the TDF vibe : I bought a rebreather, well my fourth.

One of the first things I did was get it in the pool in all the kit, yes gloves and hood, and in the shallow end (so I can reach my pile of weights on the bottom) I trimmed it for neutral buoyancy with weights in pockets et al.
Then I carefully put everything in the right pouches except for 2 x 2Kgs which I held in my hands.
Then I just hung in deeper mid water and moved my hands from my waist to sticking out in front of me until I found the 'trim' spot.
Trim is balanced so where you put yourself there you stay.
I noted the exact position of my hands and worked out the 'moment' it applied (weight * distance from my waist as roughly the balance point)
Then I worked out how much weight that was as some convenient point to actually attach it. Remember I am just moving weight now not adding or subtracting.
I fixed it there and went back in the pool. Perfect.
Camera nose down in a hole, upright or classical 'flat' deco position. It just works.
I actually look competent which is a mean con trick as I'm not.

Physics is fun

[JimmE]

To match the TDF vibe : I bought a rebreather, well my fourth.

One of the first things I did was get it in the pool in all the kit, yes gloves and hood, and in the shallow end (so I can reach my pile of weights on the bottom) I trimmed it for neutral buoyancy with weights in pockets et al.
Then I carefully put everything in the right pouches except for 2 x 2Kgs which I held in my hands.
Then I just hung in deeper mid water and moved my hands from my waist to sticking out in front of me until I found the 'trim' spot.
Trim is balanced so where you put yourself there you stay.
I noted the exact position of my hands and worked out the 'moment' it applied (weight * distance from my waist as roughly the balance point)
Then I worked out how much weight that was as some convenient point to actually attach it. Remember I am just moving weight now not adding or subtracting.
I fixed it there and went back in the pool. Perfect.
Camera nose down in a hole, upright or classical 'flat' deco position. It just works.
I actually look competent which is a mean con trick as I'm not.

Physics is fun

Heh, perhaps not quite to the same extent but I think my next pool session will be similar as I've had to switch around a fair bit of kit this year now in prep for fundies. Dives last weekend were much more comfortable than those at NDAC in Jan and Feb but I'm still not as comfortable/stable as I was in my old setup.

The club were already laughing at me for my 'full weight check' with a single 15 on a single tank wing in the pool in January - complete with drysuit/arctics/hood/gloves/umbilical torch...




Sent from my iPhone using Tapatalk

[nigel hewitt]

The club were already laughing at me for my 'full weight check' with a single 15 on a single tank wing in the pool in January - complete with drysuit/arctics/hood/gloves/umbilical torch...

Physicists doing silly things episode 5:

I tied my 5mm Hydrotech gloves and my 5mm Otter hood up in a bundle with a lead belt weight (about 1.75Kg) and dangled them in the water butt.
Out of the water they weighed 2.11Kgs and in fresh water 0.61Kgs so 1.5Kgs of buoyancy which is, I confess, quite a bit more than I expected.
(OK 150 grams of that is the lead 'floating'.)

You have to have the full kit. I put the hood on but pull it down round my neck and the gloves are taped to my wrists.
The undersuit just means it's 'boil in the bag' diver time.

[PhilPage]

Physicists doing silly things episode 5:

I tied my 5mm Hydrotech gloves and my 5mm Otter hood up in a bundle with a lead belt weight (about 1.75Kg) and dangled them in the water butt.
Out of the water they weighed 2.11Kgs and in fresh water 0.61Kgs so 1.5Kgs of buoyancy which is, I confess, quite a bit more than I expected.
(OK 150 grams of that is the lead 'floating'.)

Yeah that's a bit more than I'd've estimated

[graham_hk]

Physicists doing silly things episode 5:

I tied my 5mm Hydrotech gloves and my 5mm Otter hood up in a bundle with a lead belt weight (about 1.75Kg) and dangled them in the water butt.
Out of the water they weighed 2.11Kgs and in fresh water 0.61Kgs so 1.5Kgs of buoyancy which is, I confess, quite a bit more than I expected.
(OK 150 grams of that is the lead 'floating'.)

You have to have the full kit. I put the hood on but pull it down round my neck and the gloves are taped to my wrists.
The undersuit just means it's 'boil in the bag' diver time.

Physics is fine - but don't ignore biology ... i.e. what happens when you move your body (stretch your arms or legs for some reason), adjust body tension, or you actually use your bailout / have to rotate cylinders?

[WFO]

or you actually use your bailout ...

Total pain in the arse... with an empty steel 10 that's light as fk on one side and an al80 full of 50% on the other I end up with a right fight on my hands. I just tried this as an "I wonder" but it's a proper ball ache. I'm quite happy to manage an ascent like that but it's not helpful. It would be the same pain in the arse until you'd breathed the first 40 bar or so of 50%.

How do you mitigate for this sort of thing? Is there a trick I'm missing?