Dry Suit Diving - Help

[Mrs H]

We have just got back from our dry suit refresher. It was great to be back in the water, even if it was just a swimming pool (has it only been 3 months!). However I was totally confused by the instructions given to use my suit as the bouyancy aid. I thought this was old hat now and it was best to use your bcd.

I found it very difficult to get my bouyancy right with my suit, although I was over weighted to start with and that didn't help. We are going next week to try again, as the following week we start our rescue diver and I don't feel at all ready after my performance tonight. I want to be happy with my diving so I can concentrate on doing my best during the course.

Would it be better to use my bcd rather than my dry suit? HELP




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[Haydn]

Firstly what type of dry suit is it -Membrane or neoprene- membranes are a little tricky to get the hang of. Neoprene suits are more forgiving and you can use your bcd but don't forget to compensate for pressure squeeze (else you look like you've visited miss/mr whiplash :o ;) )

I have a membrane and use it totally for bouyancy, as do most divers with them, it has an auto dump and is great when ascending- noworries with maintaining bouyancy while dumping air.

The only advice I can give is use a combination of both and slowly reduce the bcd use as you get more confident of the suit.

Haydn

P.S. also try ankle weights it'll give you more lateral control.

[Mrs H]

Haydn

I have a membrane suit. I would say that I have pretty good bouyancy with my bcd and wetsuit, but one can always improve. I have a lady's bcd (thanks Mr H :D ) which really has helped.

Your advice seems to go against the thinking of some of the dive websites, http://www.scubaboard.com/t30692/s.html. As you will see from my post on scuba forum the majority of posts think you add some air to stop the squeeze but then use your bcd for bouyancy. I guess I am now just more confused and will end up with going with what feels best for me, which is my bcd as there is too much air movement in my suit to feel as if I am in control, and me + my bcd are old buddies :P .

I suppose it comes down to personal preferences

[kenneth_halley]

If you dive in a drysuit you should NEVER use the bcd for anything other than surface support. The problem being- should you tend to use both and there is an emergency involving an emergency lift, your rescuer is going to go for the drysuit to control the ascent. As you rise, he/she will dump the air from the suit to slow the ascent rate, but the air in the bcd will keep expanding. As you know if you are at 30metres its going to expand to 4 times the volume on the way up, so a slightly filled bcd will be very full, and you will probably have two hurt divers on the surface instead of one.

Drysuit diving is not difficult, it just requires a bit more effort to learn - especially if you are very used to a wetsuit.
Membrane suits are easiest to control, as they have no natural buoyancy, neoprene do- though again there are compressed, and crushed- with less of an effect.

While I would not advocate it for ever- , while learning and staying relatively shallow, overweighting yourself by a few pounds will help, make sure you are well balanced-, some people like ankle weights, it keeps them in a feet down head up position which leads to easier buoyancy control, as you don't start floundering about trying to get air to your dump valve.
I prefer a shoulder dump, as opposed to a cuff dump- and prefer the manual type, you can push them in to dump if having problems- you are not dependent on pressure alone to push the air out the suit. Also you can trim the sensitivity of it to dump just by slightly raising your arm or turning your body.
Be careful also what you wear below the suit, as some things have a tendency to get trapped in the dump valve preventing air from escaping when you want it to.

HTH

K

[Mrs H]

Wow NEVER is a pretty strong word and I would have thought that as long as my buddy knows what I am doing there isn't a problem. Hasn't the move to using a bc for bouyancy control been as a result of concerns regarding air movement in dry suits and an ease of dumping in an emergency situtation (http://www.baue.org/faq/dynamic_instability.html)? In a rescue situation wouldn't you check the bcd anyway to make sure it isn't inflated as you ascend?

[Haydn]

Thats interesting- if you had put the post on a UK site I think you would have got the oppersite response ie use suit for bouyancy.

Although I don't agree that the bcd should only be used for surface support I do agree that one method of control should be used. In BSAC part of the 'buddy' check is ' I'm using my Suit for bouyancy' or 'I'm using my stab for bouyancy' to assist in any emergency stuation.

Also remember, in a pool a movement of a metre is massive but at 20 metres its unimportant, plus the greatest change in pressure is between 10m and surface.

[kenneth_halley]

Fair enough to tell your buddy your using whatever for buoyancy- but consider these points- when would you NOT use a drysuit for buoyancy
1) I dare you to try go beyond about 3 metres in anything but an equalised drysuit- the crush is unbearable- so by definition the mere fact you have put air in the suit means its contributing to your overall buoyancy in the water.
2) In an emergency- and I have to say i have done it- you simply don't have time to think about all the alternatives for a lift- you go for the first one thats obvious. In all the training I did over the years- if you wear a drysuit - you lift with the drysuit, in a stab/wetsuit- use the bcd. You don't have enough hands to do all the alternatives.

...OK before some smart alec says it... you would not use a drysuit for buoyancy where you weren't wearing one :D

Feel free to disagree but these "rules" have served me well over the years

[molly]

Must agree with Kenneth here Mrs H, I dive in a membrain suit, and find that i only need enough air for bouyancy to prevent squeeze, (on very cold days i add more weight to allow me to use more air for insulation) but find even the movement from horizontal to verticle requires me to dump air, so if i was to use my bcd as well, a very quick response would be required to dump from both to avoid a possible uncontrolled accent.
Also as Kenneth says in the emergency situation your buddy will always fall back on their training IMO and expect to use only one method of boyancy control, no matter what the pre dive breifing was.
Anyway good luck with the drysuit, happy diving. :D
Mandy

[spottydog]

I found when I first got my (membrane) drysuit that it was difficult to control by bouyancy with it so I just tended to get rid of the squeeze and use my BCD. As I got more confident withh it I found myself using the BCD less and less although I still sometimes use it for some fine tuning.

My best suggestion would be just to keep on practising until you feel fully comfortable and do what is best for you.

Also when I did my rescue course (at Gildy, in dry-suits in the UK) we were tought to use the BCD for inflating/deflating in an emergency situation as the drysuit should automatically dump (with an auto dump) plus if you need to get some air in initally to start the ascent the bcd is much easier as you only need one hand to inflate and can use the other for hanging onto the unconcious diver.

[philworrall]

use only just enough air in the suit to avoid squeeze and the BCD for the buoyancy.

How may times have you tried to get out of an unexpected assent when all the air is in your feet and you are head down. As soon as it expands you will be out of conrol and the suit will not auto dump.

I can promise you it is not easy and can be dangerous.

HTH

[ahoy]

I agree with the above post and inflate the suit to counter squeeze (autodump takes care of this) and my BC for buoyancy - much easier. Also, as I use independent twins, I have my BC attached to one cylinder and my suit attached to the other - just in case.

Of course, you could always flog the drysuit and go on holiday in the Red Sea with the money - no worries about drysuits out there ;)
S.

[Mrs H]

Ahoy

Hopefully we are off to the red sea in August. We decided to take our rescue here before we go and that means dry suit diving for me ;)

[kenneth_halley]

Your not gonna use a drysuit in the Red Sea. i have seen it done but must confess it would not be my choice. I like to dive with as little clutter as poss, and pref a shorty out there- even in winter. Still very warm by our standards. The dry suit won't stay dry for very long- the sweat in it will see to that!

Plus one thing I like about diving out there is the time you can spend in the water- up to 90 mins a dive, the only hurdle being you usually need a P at some point..... there are definitley somethings even convenience zips can't help you with.!

PS. Re comments about heading balistically feet first to the surface in a dry suit.
This "should" never happen- if your buoyancy is trimmed correctly in the drysuit the initial part of any ascent should be so slow as to make it relatively simple to fin yourself down and turn yourself. Any other occurence would in my opinion be down to bad technique. You should always endeavour to maintain a slightly heads up attitude. Where some drysuits, membranes in particular tend to collect air in the feet, there are a couple of solutions, ankle weights, or straps to limit the migration of air to the feet.

OK so I know you want to get under things look under bits of wrecks and stuff, but if you are properly neutrally buoyant, you simply breathe out a bit to sink, and again no problem.
I know I am maybe being contentious to some of you but hey.... as I say befroe its served me well over the last 13 years or so of diving and not about to change these basics!

K

[Mrs H]

Sorry Kenneth I didn't explain it well. I will be dry suit diving in the UK whilst we do our rescue diver. In the red sea I shall have my wetsuit on. I should think you would have heat stroke before you could get in the water if you wore a dry suit in the red sea :wacko:

[kenneth_halley]

A lot of the Guides and instructors dry dive in winter out there as they feel it cold after the warm summer months. Like you say heat stroke seems more of a prob than freezing!
Always feels warm to me!

[Kira]

Hi All,

I worked/owned Channel Diving out off Brighton.

I had a Northern Diver dry suit, I was at 42m in the middle of the English channel diving on an old ww2 liner when the valve stuck open on the front of my suit, and without me knowing, was filling my boots up with air, all of a sudden I was fighting with my feet as all they wanted to do was go skywards, if it had not been for the fact that my dive buddy was within reach and that I was able to grab hold of the wreck, I don't think I would be telling you this now. to cut a long story short, I managed to disconnect the free flowing valve, which then dumped all the air that I had left within seconds, I then buddy shared back to the surface, That took about an hour with stop's, when we got back on board we were BOTH out of air.

IMO, Only put enough air in your dry suit to make it comfortable, but not too comfortable.

Kira.

[Andy Hipkiss]

Kenny,

I must admit I have the same concerns as my wife, although I freely admit this is down to lack of practice ... the whole concept of cold water diving is complete madness to my mind ... and yes I'm a wimp :D A Weezle Extreme undersuit sounds about right for July diving in Stoney.

More seriously I was incredibly unimpressed with my D/S diving in the pool ... yes sure it's all shallow so weighting / buoyancy is more pronounced but I wasn't HP. I'm pretty confident with my wetsuit diving so it came as a real bump to earth how poor I was with my old drysuit on ... grrrrr. The thing that really scared me was the weight I used to carry during my foolish youthful days in a D/S. I reckon it's about 8 lbs more than I think I need and I'm about the same weight as I was then. Perhaps experience and confidence plays a part but I just can't believe I seriously thought I needed so much weight all those years ago :(

Having followed the Scubaboard thread I am kinda at a loss now. Considering the vast majority of my diving is warm water, I feel vastly more happy using my bc for buoyancy, and merely putting the minimum of air in my ds to avoid the worst of the squeeze. But that's an inexperienced ds diver speaking ... but the big question for me is how to compromise ... I know that ds diving will form maybe 10% of my diving (at best!) so what to do.

The diving community seems totally split over the issue :( So IYE ... bearing in mind I'm a big girlie and prefer warm water diving, would you focus on bc or ds buoyancy control? Much as I buy into the theory that a ds can be used for buoyancy, a little voice (shhhhh little voice! ;)) keeps on saying a bc is for buoyancy.

[kenneth_halley]

Well call me old fashioned- and all my diving mates too.... but when in a drysuit, a drysuit is used for buoyancy control. With proper weighting there is no need to over inflate it. This can make descent a little slow , I always fin down the first metre or two with the suit empty to kick things off.
I use a ND compressed Neoprene suit which has a little natural buoyancy. Dependent on time of year and how much I wear under it I need about 24lbs weight. Can get away with less but more effort required on a shallow dive or if strenuous.

The only reason I wear a bc (in my case a wing) at all is to hold my bottles. Some mates don't even wear that- preferring just a harness. So only the drysuit to think about.

Yep- I have heard of people in situations like Kira mentioned, but equally I have heard of people getting their stabbies jammed on with air in too, the effect is the same. If you have two sources of buoyancy to contend with and the same thing happened, as kira mentioned- you would be in real dificulty, especially in a feet up attitude, the stab dump valve is usually at the high point- the shoulder, though I know many do have a bottom dump too- my wing does, but spending time on thats not emptying the suit and vice versa.

My feeling is get used to one method for buoyancy and stick to it when diving in that configuration. Practice makes perfect. when it all goes t£ts up with two systems in play you are asking for serious trouble IMHO. Like you acknowledge a swimming pool is not an ideal environment to try a drysuit in, too shallow so you need a lot of weight to stay put on the bottom. in open water though getting your weight right means this is not really an issue once over 3 metres down staying there is pretty easy.

On hols- I dive in a shorty, with the wing and bottles, and use that. I would freely admit that I enjoy diving in a wetsuit (no suit even) more, but in Scotland its only practical in summer shore diving. Sat on a boat in winter waiting for your surface interval to expire for a second dive, in a wetsuit is not funny- been there done that got the drysuit! :D

On hols diving in a wetsuit feels so ridiculously easy compared to the drysuit, but its horses for courses, and drysuits are for here, no question. I think being good with a dry suit makes you much better as a diver generally- buoyancy control wise, its like riding a bike really.

but- hey- each to their own.

K

[Andy Hipkiss]

Well call me old fashioned-

Not at all, I would call it experience.


This can make descent a little slow , I always fin down the first metre or two with the suit empty to kick things off.


Ditto, I find exactly the same in my wetsuit .... seems to make the safety stop at the end of the dive much easier.

I use a ND compressed Neoprene suit which has a little natural buoyancy

Do you prefer them over membranes? I've never tried one but it seems from what I've read that a neoprene ds is a pig. Uncompressed at the surface but compressed at depth.

I wear a bc (in my case a wing)

Strange that ... I've moved away from a wing and on to a Cressi S-111 ... for some reason I couldn't get on too well with my Zeagle (is this what you would call a wing?). Dunno why but I came to loath my Zeagle. OK, the S-111 is Mr Cressi's personal design but my cynicism calls that marketing, even though I hate diving with any bc but the S-111 now ...

Note however, the S-111 is a complete bitch to pack for traveling :(

I have heard of people getting their stabbies jammed on with air in too, the effect is the same.{/quote]

I think the safety issue is a matter of training ... either can fail it's just where your rescuer tries to dump air from. The UK diver would do the left arm trick, the rest would reach for the bc ... who knows ... hence my question above.

[QUOTE]On hols- I dive in a shorty

That I find fascinating .. I'm dead against shorties for several reasons ... not least as I've had the pleasure of doing my 5-3m stop in the middle of a hydroid plague on a couple of occasions. Why a shorty over a .5 or dive skin out of interest?


Just picking your brain and any info I can get from you is appreciated.



edit: grrr the quote stuff doesn't seem to work properly ... sorry

[Haydn]

Sorry to open this debate again (not really ;) ) but I was looking in Dive mag for August and there is one of those '50 ways to be a better diver' things and one caught my eye. I quote 'Work on correct weight for bouyancy. If you are diving in a drysuit, use only the suit inflator and dump for bouyancy control'


I would not have bothered to post it here but the list was compiled by the great and good in BSAC who are (argueably) some of the most experenced and knowledgeble divers in this country.......

I won't make any other comments (coz I'm a coward :D and don't wan't to upset our American allies)

Haydn

[kenneth_halley]

Haydn

arhemmm. don't like to say I told you so,so I won't ;)

Andy
Sorry I rather missed your query- better late than never eh?

Re the Neoprene drysuit. Yes an uncompressed Drysuit is a complete pig, and I personally could not get on with one. Compressed is not anywhere near as bad- and pretty tough. Most of my colwater diving is wrecks and these can take the knocks. I never really liked membranes, did my initial training in one as a novice and always felt like I had an elastic band round my neck. I personally think a neoprene neck seal is superior comfort wise. JMHO
Also you don't need to wear a big thick undersuit, due to the natural insulation. have to say though I have a bad knee these days and best suit I have tried is the DUI Crushed Neoprene. they have downsides though- Expensive, your back to needing an undersuit and the feet seem a bit crap though the over boots are dead comfy.... but you can fit a neoprene seal!

Re Wings- have to say I am easy, I got a wing as a replacement for a BC, that was shaggered . I do feel a bit less cluttered in it, though the surface support aspects are not as good as a BC. Then again a lot of guys I know don't wear any sort of stab/bc, just a DS and harness.

I was always a bit anti shorties, preferring a full suit, though dived in Mexico a long time ago in nothing but a t shirt and trunks and it was great. I did however get a bit hydroid burn on a wreck , on my arm- that'll teach me!
Having said that- I rarely touch anything when diving abroad, most of my foreign diving has been Red Sea and never got so much as a sting or a cut. The min reason though for me using the shortie is this daft leg of mine. My knee is basically destroyed, andthe pressure of a tight suit against it makes a wetsuit really uncomfortable for me, the Shorty solves the problem, I can fin comfortably with no probs, in it, and am warm as toast too!