Drysuit - Managing the air bubble?

[swimmingsheep]

I went out about a month ago and put 8 dives on my brand new drysuit and I completed the PADI drysuit specialty! I had some observations I'd like to share and get some pointers and feedback on.

The suit is 3mm crushed neoprene and I was wearing a thin layer of athletic clothes underneath. I suspect I was a little more than a "little" overweighted, diving the 12lb weight belt plus four 4s (two in front and two in back) I use with my 7/8 semi-dry, plus 2s as ankle weights, for a total of 32lbs. But I was told you always need more lead when diving dry. Could I need less lead in my drysuit?


I used it primarily for buoyancy and at some points during the dives I noticed the chest and arms of the suit were completely full and when I went to add more air it would dump immediately, at the same time I'd feel a squeeze on my legs. Why doesn't the bubble spread out more?

I wonder if the bubble's tendency to stay in my arms and chest played into my trim troubles? I was head-up during the hover and had to fight to keep proper trim. If my suit's legs weren't so long I'd consider diving without ankle weights, but I am always concerned I will lose my feet and those seem to keep everything where it belongs. I wear the ditchable pockets and weight belt high on my waist. Should I try a lighter ankle weight? Should I try putting weights on my tank valve?

Thank you for the comments and suggestions!

 

[nimoh]

the gas in the suit will migrate to the highest point, and because of this the bubble is managed by changing what point is the highest point. For example, if you find you are getting too much gas in your feet, then drop your feet and the gas will move into your torso.

If you are finding that your torso is completely full and you have a squeeze on your legs, then you are not in trim. However, if you are almost in trim, it may take a while for the gas to migrate out of your feet, but it will. So, at the first sign of an imbalance, make a small adjustment such as dropping your shoulders temporarily and drive a little gas into your legs.

It does sound like you have a lot of gas in your suit, I think the first step would be to get properly weighted.

 

[RJP]

Two things:

1.) With that much air sounds like you may be overweighted
2.) Use suit for warmth, BCD for buoyancy control

---------- Post added April 1st, 2015 at 01:57 PM ----------

I used it primarily for buoyancy and at some points during the dives I noticed the chest and arms of the suit were completely full and when I went to add more air it would dump immediately, at the same time I'd feel a squeeze on my legs. Why doesn't the bubble spread out more?

You're obviously diving in somewhat of a feet-down position. The bubble can't spread "down" so will collect in shoulders and arms. As you've suggested, this will worsen your trim even more.

You oughta look like this in a drysuit... if I do say so myself. :cool2:

 

[rhwestfall]

are you diving a jacket BC, back-inflate, or a plate? That seems to be a lot of lead....

keep in mind, everything with a DS (at least to me), needs to be slow, deliberate, baby steps, and almost preemptive rather than reactive. More dives should allow you to drill down to things you can change. If you can, ditch the ankle weights. Nothing but "trouble". I weened myself off them by going to gaiters, and still like them.

 

[FishLovingStudent]

The suit is 3mm crushed neoprene and I was wearing a thin layer of athletic clothes underneath. I suspect I was a little more than a "little" overweighted, diving the 12lb weight belt plus four 4s (two in front and two in back) I use with my 7/8 semi-dry, plus 2s as ankle weights, for a total of 32lbs. But I was told you always need more lead when diving dry. Could I need less lead in my drysuit?

I used it primarily for buoyancy and at some points during the dives I noticed the chest and arms of the suit were completely full and when I went to add more air it would dump immediately, at the same time I'd feel a squeeze on my legs. Why doesn't the bubble spread out more?

I wonder if the bubble's tendency to stay in my arms and chest played into my trim troubles? I was head-up during the hover and had to fight to keep proper trim. If my suit's legs weren't so long I'd consider diving without ankle weights, but I am always concerned I will lose my feet and those seem to keep everything where it belongs. I wear the ditchable pockets and weight belt high on my waist. Should I try a lighter ankle weight? Should I try putting weights on my tank valve?

1) Most likely not. I don't know your size but I wear 32-36lbs with my shell drysuit so I would not be surprised if you might need even more weight in a neoprene.

2) Lift your legs up and air will travel there.

3) The bubble moves according to your trim, not the other way around. The ankle weights are there to lower your feet but are not necessary with some practice. It depends on the individual of course, my significant other uses light blade fins and finds it just right without ankle weights. I wear heavy F1s and find it just right with them, but don't need ankle weights when I switch to lighter fins.

 

[RJP]

.

keep in mind, everything [-]with a DS[/-] about diving in general needs to be slow, deliberate, baby steps, and almost preemptive rather than reactive.

Fixed it for you.

 

[rhwestfall]

amen!

 

[MXGratefulDiver]

I went out about a month ago and put 8 dives on my brand new drysuit and I completed the PADI drysuit specialty! I had some observations I'd like to share and get some pointers and feedback on.

The suit is 3mm crushed neoprene and I was wearing a thin layer of athletic clothes underneath. I suspect I was a little more than a "little" overweighted, diving the 12lb weight belt plus four 4s (two in front and two in back) I use with my 7/8 semi-dry, plus 2s as ankle weights, for a total of 32lbs. But I was told you always need more lead when diving dry. Could I need less lead in my drysuit?


I used it primarily for buoyancy and at some points during the dives I noticed the chest and arms of the suit were completely full and when I went to add more air it would dump immediately, at the same time I'd feel a squeeze on my legs. Why doesn't the bubble spread out more?

I wonder if the bubble's tendency to stay in my arms and chest played into my trim troubles? I was head-up during the hover and had to fight to keep proper trim. If my suit's legs weren't so long I'd consider diving without ankle weights, but I am always concerned I will lose my feet and those seem to keep everything where it belongs. I wear the ditchable pockets and weight belt high on my waist. Should I try a lighter ankle weight? Should I try putting weights on my tank valve?

Thank you for the comments and suggestions!

Given what you describe I would suspect that you're overweighted. You should not feel like your chest and arms are completely full ... whether you're using your drysuit or BCD for buoyancy control, if you're properly weighted you should only have enough air in the suit to remove the squeeze. That said, it would be difficult to tell whether or not you're overweighted without doing a proper weight check. Try this test ... with only your reserve gas (500 psi) in your tank, swim to a depth of 8 fsw, find a flat sandy area and attempt a fin pivot with all the air removed from your BCD and drysuit. If you can do a fin pivot ... rising on the inhale and falling on the exhale with no air in either suit or BCD ... you are properly weighted. If you need to add air, you're carrying too much weight. Slowly remove weight ... 1-2 lbs at a time ... until you can perform the fin pivot.

Second issue ... why doesn't the bubble spread out more? Well, because you're not in trim. Air will always rise to the highest point it can get to ... it's constantly trying to get to the surface. So if you have bunches of air in your torso and arms and a squeeze in your legs, that's telling you that your legs are lower than your torso and arms ... in other words, you're not in proper trim. So it's not that the bubble's tendency to stay in your arms and chest played into your trim troubles ... it's that your trim troubles created that problem.

Third issue ... why are your suit's legs so long? Didn't they fit your suit properly? A good fit is the #1 "feature" you should go for on any drysuit. If the legs are too long, consider getting them shortened. A poorly fitted suit will trap air and create exactly the type of problems you're describing.

Fourth issue ... weight distribution. If you're not properly in trim, you should absolutely consider moving weights around to help you become that way. I'm surprised they didn't cover this in your drysuit class ... they certainly should have.

I can't get any more specific than that without seeing you in the water and seeing what gear you're using. But you're in my area, so if you'd like to hook up some evening at Cove 2 I'd be happy to take you diving and see if I can help you get squared away. You don't need another class ... you just need somebody who understands how it's supposed to work to look at you with a critical eye and help you get yourself squared away. Drop me a PM if you're interested and we'll work out the details offline.

... Bob (Grateful Diver)

 

[James R]

These issues should have been handled during your confined water and, at last resort, first open water dive. Your suit being so full that it dumps immediately tells me that you're almost certainly overweighted! Did you do a proper weight check at the end of confined or the fist open water dive with an empty (500) tank? Honestly, I would start there and stop throwing weight in places you may not need it (ie ankle weights b/c you're concerned your feet will float away). I don't want to bag on your instructor too hard, but from what I am reading you probably need more instruction (or a good mentor since the class is done now) and less guessing at stuff.

 

[BRT]

Athletic clothing may not be the insulation you need. If you don't have enough THICKNESS of insulation the air you are using for insulation will move rapidly up and down and the down part of the suit will be cold and tight. When you get a thick enough undergarment you may be less overweighted and not notice the bubble so much.