Diving Dry? Balance your Rig!

[GrumpyOldGuy]

Ditching you lead is not a good plan. Let's assume there was a typo.QUOTE]

... and that thinking is perhaps why so many people are found on the bottom still wearing their lead.

Ditching lead is a great plan if the alternative is drowning. Far too many people take away from these discussions that ditching weight at depth is a death sentence. It is not. Ditching 25 lbs at 130 feet might be a problem but I would choose even that if the alternative was drowning.

Once watched a fairly new drysuit diver lose their weightbelt at 80 feet or so. Buddy grabbed the weights from the bottom, chased the diver up and brought him back down. Yes he was on his way to the surface with no way of stopping, but was able to slow the process sufficiently to allow the buddy to fix the problem. If he had gone all the way to the surface the likelyhood of damage was minimal - he was able to slow the rate of ascent to something manageable by venting everything and then swimming down.

If you flare you simply can't move through the water that fast. Yes you will be going up faster than the recommended 30 feet a minute, but you will not be a polaris missel either.

I personally carry three sets of ditchable weights. A weightbelt with 8 - 10 lbs and two pouches with 4lbs each on the BC harness. Weight belt is easy to ditch - pouches are a bit harder, but still pretty simple. Lead is cheap, ditch the weight.

All this goes away if you are talking tech diving where an uncontrolled ascent IS NOT an option.

I carry my weight in a harness so I can do a partial ditch too. Its still not a good plan for a BCD failure, better than drowning of course. Its pretty much a last resort move at depth. Drowning due to BCD failure is stupid, there is no reason for it.

I don't have stats, but I suspect that many people who drown after failing to ditch weights are at the surface at some point in their struggles and fail to achieve the positive buoyancy needed to stay on the surface.

 

[gypsyjim]

I would suggest that in wet suit diving the idea of a balanced rig has a lot of importance too.

 

[Darnold9999]

Well, if you remember, he WAS wearing a drysuit....Why didn't he just push the inflate button? "I knew I had a drysuit, I pushed the button to inflate it, and it the air just escaped the exhaust valve." So why didn't you close the valve? "I knew I could, but in my panic, I just couldn't think how to do it....I froze."

Not why I do it, but I have changed my default to diving with the dump valve closed. I have a wrist dump so really easy to get to and turn on and off, but I found that I rarely want to dump air automatically and too often I would be venting automatically when I really didn't want to, both with the shoulder dump and wrist dump. Much prefer to just open and dump as required then close again. Interestingly it means that opening and closing the valve is now automatic - as is topping up the dry suit. So much so that if I am diving wet, for the first few dives I reach for my chest and wrist to adjust boyancy and have to remember to go for the wing. Mostly a photographer thing as I am more often than not in some odd position trying to get a shot and with an open dump valve air starts to vent and I have to back out close the valve add back the air to the drysuit and reposition.

A really good story. My takeaway. Always check all things that require air just before splashing. I always do three breaths from the main, and a shot to the BC and a shot to the drysuit. EVERY time just before splashing - feels stupid sometimes, but I can survive just about anything with lots of air. I can get complacent about a lot of things, but this is an infallible rule for me. A test I never skip. Have managed to jump in sans fins, weights, computer, mask, camera but so far never without working air.

 

[elan]

Ditching you lead is not a good plan. Let's assume there was a typo.

Add a set of steel tanks and you probably can't swim it up and ditching the tanks is not an option. You need redundant lift, via dry suite, 2nd bladder or SMB (dicey). Choose one.

Diving a drysuit with steels goes without saying.
no ditching weight is not a typo. One needs to carefully an weight distribution between pockets so ditching a pocket does not make you a rocket but compensated for buoyancy loss.

 

[GrumpyOldGuy]

Diving a drysuit with steels goes without saying.
no ditching weight is not a typo. One needs to carefully an weight distribution between pockets so ditching a pocket does not make you a rocket but compensated for buoyancy loss.

So what you are saying is the concept of a balanced rig does not include anything removable. Sorry it does not make sense to me, heck its all removable if you think about it. Here are your words...my underline.

"Not the fill rig, only the non. ditchable part. Those parts that can be ditched (stage bottles, lights, ditchable weight) are not taken into account"

I assumed we just miss communicated. I would contend anything attached to you or your rig will affect if it is/is not balanced. The fact that you can ditch it may help you make an emergency ascent for sure, but as a plan I think it is rather poor, my words were a plan of last resort. There are much better methods that allow more control.

 

[swimmer_spe]

The recent death of a scubaboard member (Link) while trying to adjust to a new drysuit prompted this post.

Whether new to drysuits or not, it's crucial to "balance" your rig.

A few questions based on that discussion.

- Do you know what it means if the rig is balanced?
- Are you aware of the risks if your BCD can't hold you up on the surface without additional positive buoyancy from the suit?
- Are you aware of how much ditchable (and unditchable) weight you have and are you able to deploy it easily?
- Are you aware of how much ballast (weights) you need and how to make "stepwise" adjustments when adjusting things like undergarments?

I guess you can say that the same applies to wearing a wetsuit but in a drysuit the "gotchas" might not be as obvious.

Please discuss.

R..

Try this: Go in a pool. Flood your dry suit. Are you swimming up? How bout with your gear on?

There are risks to everything, Mitigating those risks are more important than fearing them.

Most dry suits, with a full BCD and all weights dropped will likely not bring you to the surface when full of water...(but I might be wrong on this)

 

[dive_turkey]

Try this: Go in a pool. Flood your dry suit. Are you swimming up? How bout with your gear on?

There are risks to everything, Mitigating those risks are more important than fearing them.

Most dry suits, with a full BCD and all weights dropped will likely not bring you to the surface when full of water...(but I might be wrong on this)

We are headed to the 10m pool this weekend to play with my buddy's weighting. I was planning to tinker slightly with mine, but for the most part am going to support his efforts. It had not occurred to me that I should probably test flood my suit at least once, and preferrably in the nice 30-c water. Any suggestions for this procedure? I know I should practice the way I dive, but I'd prefer not to have to drive 2 hours home with soaked undergarments bagged up in the car. Shouldn't be too different to flood the suit with just a swimsuit on, right? Better to do this through a wrist/neck seal or with the zipper? Also, how difficult is it going to be to exit the water? Should I be worried about tearing a seam with the weight of the water? The pool we are going to has a platform at the top that you can stand on, putting the water about chest deep. I suppose I can doff the suit there to mitigate the weight.

So, in summary:

-10m of water, 30 degree celsius.

-Plan to complete 3 dives in the day for the purpose of designing/redesigning weight/bouyancy from the ground up. I was instructed as PADI, which means using the suit for bouyancy. I plan to get away from this and start practicing with my BC (Zeagle Ranger LTD).

-Want to distribute weight in two places. The Ranger has integrated weight pockets with a ripcord ditch system, and my Mako weight belt.

-Diving a Mares TechFit LX Tri-Lam suit with shoulder dump valve and silicon seals.

Can someone help me plan the best way for my buddy and I reach our goals? I assume the suit flood should be the final test. The 3m hover at 35-50 bar should be the last check at the end of all three dives (switching to fresh tanks before attempting the suit flood). Need to determine the amount of weight required, and the amount of weight that needs to be ditchable. Need to practice swimming up with bladder failure, suit failure, and catastrophic failure of both.

What other tests should we conduct? What are the best methods? What order should we conduct them in? It's a two our drive and 40 euro a piece for the pool. We really want to make the best of our time there, and come out with good plans for weighting and bouyancy for each of us.

 

[elan]

So what you are saying is the concept of a balanced rig does not include anything removable. Sorry it does not make sense to me, heck its all removable if you think about it. Here are your words...my underline.

"Not the fill rig, only the non. ditchable part. Those parts that can be ditched (stage bottles, lights, ditchable weight) are not taken into account"

I assumed we just miss communicated. I would contend anything attached to you or your rig will affect if it is/is not balanced. The fact that you can ditch it may help you make an emergency ascent for sure, but as a plan I think it is rather poor, my words were a plan of last resort. There are much better methods that allow more control.

Ok I will try to give a couple examples (assume a wing failure)
Diving a dry suit with AL80 full of Nitrox and 3 stages full of the same nitrox. Perfectly weighted without stages I will be overweight by the weight of gas - about 10-12 lbs , with the stages it will be another 15 lb of gas. And will be another 12-15 lb negative so in total it is about 25-27 lb negative and there is no way I can swim it up. Does it mean Im not balanced? No Im balanced because I can ditch the stages and swim 10-12 lb to the surface. ( I tested this)

Now another example is diving a set of HP130 full of Nitrox with no ditchable weight would be unbalanced as it will be about 20lb of gas in them and it is hard to swim that up unless you are an athlete. Now if the configuration of you rig is that it allows you to have some of uour weight ditchable while being properly weighted, say 8 lb, you can ditch those 6 lb an that will make it more managable.

Or if you dive the same HP130 set with 18/45 in them instead of nitrox plus 5 stages and deco tanks it will also be balanced because the gas in doubles will weight around the same 12 lb and you can ditch the stages and deco bottles.


Of cause we then come to a question about whether we have any deco obligations and such but then you have to an further and prioritize. Carry backup lift bag etc.
Of cause you can remove the whole rig always but I do not think it is a good idea if you dive dry an do it at 150 ft.

 

[GrumpyOldGuy]

Ok I will try to give a couple examples (assume a wing failure)
Diving a dry suit with AL80 full of Nitrox and 3 stages full of the same nitrox. Perfectly weighted without stages I will be overweight by the weight of gas - about 10-12 lbs , with the stages it will be another 15 lb of gas. And will be another 12-15 lb negative so in total it is about 25-27 lb negative and there is no way I can swim it up. Does it mean Im not balanced? No Im balanced because I can ditch the stages and swim 10-12 lb to the surface. ( I tested this)

Now another example is diving a set of HP130 full of Nitrox with no ditchable weight would be unbalanced as it will be about 20lb of gas in them and it is hard to swim that up unless you are an athlete. Now if the configuration of you rig is that it allows you to have some of uour weight ditchable while being properly weighted, say 8 lb, you can ditch those 6 lb an that will make it more managable.

Or if you dive the same HP130 set with 18/45 in them instead of nitrox plus 5 stages and deco tanks it will also be balanced because the gas in doubles will weight around the same 12 lb and you can ditch the stages and deco bottles.


Of cause we then come to a question about whether we have any deco obligations and such but then you have to an further and prioritize. Carry backup lift bag etc.
Of cause you can remove the whole rig always but I do not think it is a good idea if you dive dry an do it at 150 ft.

Now I think I understand were you are coming from. Dropping some lead to counterbalance the weight of gas in a dive with lots of gas. I still dive wet often (2/3 of my dives) and dropping weights is bad because I am fighting the expansion of the neoprene. Since this is a D/S thread, it does not apply. So your logic does make sense. The communication issue was mine.

Personally, my D/S is a bit big on me and can provide more redundant lift than I will ever need, so when diving dry wing failure is not an issue.

 

[Diver0001]

There are risks to everything, Mitigating those risks are more important than fearing them.

Totally agree and that's why I started this thread. I want people to take the lessons we learned from Quero's death and apply them.

Getting back to the OP.

To my way of thinking you should be able to reach the surface and stay there with

Either the BCD OR the suit with weights in place.

To me that's balanced. With at least one of your buoyant bodies intact, if you drop weights then you're not going to have the problem that Quero had.

In our tech training we were trained to use a DSMB and a lift bag as a back up but it was not a back up for *getting* to the surface, it was intended to be an extra safety factor to maintain positive buoyancy once on the surface. We did do some kind of skill/experiment to use a DSMB as an aid for making an ascent with an empty suit and an empty BCD but to me it was only proof positive that you need a better "plan B" than that! I think that might have been the point of the exercise.

I really appreciate all of the comments on this thread. Keep them coming! One of Quero's legacies is going to be that people are going to be more aware of the risks involved in diving unbalanced rigs. The more of us who get that word out there and share that insight with our fellow divers, the better. Thanks to all.

Most dry suits, with a full BCD and all weights dropped will likely not bring you to the surface when full of water...(but I might be wrong on this)

I've had it happen. I knew the zipper was on its last legs but I tried to dive with it anyway. Got in the water, made a twisting motion and *woof* suit empty, shockingly cold water down my back and sinking. I got back to the surface fine using just the wing, at least enough to keep my head above water, but needed quite a bit of help getting out of the water. I think there may have been 20 litres of water in the suit. The thing about water is it's neutrally buoyant and only really starts getting heavy when you try to lift it above surface.

As an aside, that was during an OW course and I used it as a learning tool, telling my students about proper weighting, the importance of positive buoyancy on the surface and how even experienced divers need to be reminded some times about the importance of proper gear maintenance. I couldn't have thought of a more dramatic demonstration if I had tried LOL

R..