Need help with BCD/drysuit weight issue

[Wesley_R]

I recently got my PADI OW cert, and have done a total of 6 dives in Maui. These dives were with a 5 mm full wetsuit, 63 cu ft AL tank, and Cressi S111 BCD. I used a total of 16 lbs of lead in the BCD's front integrated pockets. I had excellent buoyancy control and trim for a newbie, and felt very comfortable during the dives.

This past week, I got into the pool for the first time with my new Bare XCD2 Tech drysuit, OS Systems dry gloves, 5 mm hood, undergarment, Cressi S111 BC, and 80 cu ft steel tank.

After about 30 minutes of my instructor and I trying to figure out what was going wrong, I chose to abort the session to give the other students their opportunity.

The basic problem was - I continually "fell backwards" upon descent (descending with my back toward the bottom). My feet always ended up way higher than my head, even with 1.5 lb weights on each ankle. When I tried to roll onto my belly and swim, I kept turning turtle. We tried various amounts of weight in the BCD pockets, between 16 and 30 pounds total.

I have not had the chance to get back into the pool again, or even discuss the situation with my instructor.

Obviously, the weight distribution was way off - too much to the rear, or some other major factor. This was a very discouraging session, and I am trying to figure out why things could be so far off, and what to try next time.

Any sound advice would be greatly appreciated.

 

[runsongas]

put less air in the drysuit and use the bc for buoyancy. sounds like your bubble is too big and you are getting inverted.

 

[Wesley_R]

With a drysuit, the BCD is only used to attain positive buoyancy at the surface, and should be total deflated upon descent. Buoyancy control while submerged should only be done via the suit. During this session, I had exhausted as much air as I could from the suit prior to entering the water.

 

[tbone1004]

First off, you had far too much lead in Maui, but that's besides the point.

Second bit, is if this situation confused your instructor, then he is unfortunately not very good.

Third bit is what runsongas says. You need to use the bc as a bc, and the drysuit as a drysuit. Many instructors try to teach you to manage one bubble in the suit, which with a single AL80 you can do, but when you move on, you can't do that without issues.

16lbs of lead is about right for a drysuit, stab jacket, and AL80. You need to ditch the jacket bc ASAP, that's problem #1. They are inherently unstable without a crotch strap, and the way they work, they try to push the bubble in the suit to the front. Wrap around design isn't very good, and combine that with how tight they have to be to keep from moving around, and the bubble in the suit can't move to your back where it wants to go. With a BP/W, this issue isn't nearly as bad. Not to say you can't dive dry in a stab jacket, but a BP/W is infinitely better in this situation. Your instructor putting 30lbs of lead on you is a crime, you don't need that unless you're ice diving or trying to walk on the bottom of a river. It's just too much lead. Not sure where you are, but it sounds like you need some different assistance in person on this...

---------- Post added August 2nd, 2015 at 07:56 PM ----------

With a drysuit, the BCD is only used to attain positive buoyancy at the surface, and should be total deflated upon descent. Buoyancy control while submerged should only be done via the suit. During this session, I had exhausted as much air as I could from the suit prior to entering the water.

That might be what the PADI book says, or what your instructor taught you, but the reason they wrote that is because they don't think new divers can manage two bubbles. This is ridiculous. You can vent the drysuit and the wing simultaneously, so there is no need to dive like this. With an AL80 it's only an extra about 4lbs, but you get into tech diving, and do that, and you're going to kill yourself. Last drysuit dive for me was 2 HP120's, and 2 AL80's, plus decompression bottle. That is over 400cf of gas, and about 35lbs of gas. You will literally kill yourself trying to maintain a bubble that size in the drysuit.

No offense, and really not meaning to be rude, but regardless of what the book says, your instructor clearly doesn't know what was wrong with you and isn't truly qualified to teach you how to dive in a drysuit. Immediately going to ankle weights, putting on 30lbs of lead and telling you to not use your BC for buoyancy control is frankly terrifying.

 

[brphilli]

Try not to feel too frustrated, you changed a lot of variables at once moving from a wet suit with AL63 to a dry suit with a steel 80. Much more experienced divers would have found this a challenge, a new learning curve is to be expected.

First step with all that new gear is do a buoyancy check to get your weight sorted properly. As tbone said, in that kit, 15 lbs would seem about right but would depend on the undergarment (which for a pool session I would assume was pretty minimal). 30 lbs would have meant a massive bubble that would have been really difficult for a newb to manage. Once you have determined the proper weight for your kit, problems are never solved and are often created by adding more weight. You may need to distribute the weight differently to achieve proper trim but adding weight is not a good idea. If this problem existed when you were properly weighted and with no air in the dry suit, then it was a weight distribution problem, not a bubble management problem.

I would suggest starting out with what was familiar, add just enough air to the dry suit to be comfortable with no pinch and then achieve proper buoyancy with the BCD. If properly weighted, you shouldn't need to add very much air to your vest. A BP/W has many benefits, which tbone has mentioned, but you shouldn't need to immediately switch. I doubt the BCD was the issue in this instance.

I too was originally taught to only use my BCD at the surface when dry suit diving so that there was only one bubble to manage. This is fine for singles if you are weighted properly, a nightmare if you are overweight. For new dry suit divers, the air in the suit is often more difficult to manage as it has further to move around, so having only enough air to be comfortable in your suit and maintaining buoyancy with your BCD is often easier and simpler.

Long and short, get back in the water! Using the proper weight and using your BCD for buoyancy will likely solve this issue. Then play around with what mix of air in the suit and BCD you are comfortable with and have fun!

 

[JohnnyC]

Your basic problem is you went from zero experience in one type of diving setting, to zero experience in a completely different type of diving setting, with an instructor who doesn't understand what he's doing.

Read what tbone wrote. Then read it again, and a third time, then go do what he said.

 

[TSandM]

I did all my descents for my first 20 dives by falling on my back . . . it's something that happens easily with steel tanks, because they are negative and want to pull you backwards. NW Grateful Diver fixed it for me, by telling me to bend my knees a little on the surface, and cross my ankles. Then I couldn't fin myself upwards, and the fins being out behind me would catch the water and rotate me belly-down on descent. I never fell onto my back after that.

Air in the feet is an occupational hazard of dry suit diving. It is made worse by a) too much air in the suit; b) too much weight high up on the body, and c) a tendency to look down. Putting negative fins on your feet helps, which is why a lot of dry suit divers use the heavy, negative rubber fins. Something to compress the boots, if you are using a suit with attached boots, can also help (finkeepers). Checking static weight distribution can make a big difference -- for example, if your BC has trim pockets in the back which are up on your shoulders, and you are putting too much weight in them, it makes it quite hard to stay horizontal. Your instructor should, in theory, know how to evaluate your total weighting and your weight distribution to get things set up for easier diving, but some instructors are better at this than others.

But in the end, one of the skills of dry suit diving is managing the bubble in the suit. You have to become AWARE of where the air is, and act to redistribute it before it causes you trouble. If your feet feel loose and sloppy, get your head UP! Because when it comes to dry suits, an ounce of prevention is worth a TON of cure.

 

[tbone1004]

oh, other personal preference thing.
I hate integrated boots
I hate overboots

One of the nifty things I learned once I started diving around Marianna was those guys are all diving with wetsuit booties over the neoprene socks. This is magnificent if you have issues with your feet ballooning.

As far as the surface goes. Of course you're rolling on your back. You have a stab jacket designed to put all the lift around your belly, with a tank trying to pull you backwards. If the weight on your belt was towards the back, you haven't a prayer of making a proper descent. Get a BP/W, it will put the lift behind you, then you can stay easily at the surface of the water vertical, roll on your back like Baloo to take a nap because it isn't trying to suffocate you, and when you want to descent, you just pull your ankles up underneath you, and you roll back to vertical if not slightly forward, and then descent is easy.

This is a skills and equipment problem, that really need an equipment solution before trying to fix the skills. You're fighting an uphill battle. Extra weight is an equipment solution to a skills problem, the problem there being your instructors lack of skill.

So. Sequence of events
Step 1. Find a new instructor who knows what they're doing, alternatively, ditch the instructor and find a good mentor. If you have half a brain, teaching someone to dive a drysuit safely takes like 10 minutes in a confined water session. This is how you inflate, this is how you dump. If you go feet up, give a hard frog kick while arching your back to get yourself back to vertical and dump. Not much else needs to be said about that.
Step 2. If you have a drysuit with neoprene socks, switch to neoprene booties, if you don't own a suit yet, don't buy one with integrated boots, and don't pay for overboots. *unfortunately I can't follow my own advice because they barely make booties big enough for my feet as it is and they don't have any wide enough in the drysuit with socks on....
Step 3. ditch the jacket, get a SS bp/w. I highly recommend calling Tobin at Deep Sea Supply and buying whatever he tells you to buy. It'll cost you $500, but it will be the last rig you have to buy, and it will be money much better spent.
Step 4. If you don't own a drysuit, call Mike at Dive Right in Scuba, and buy whatever he tells you to buy. Reasons same as above, just with cost being about $2k ish.