Buoyancy Control: Drysuit VS BC, VS Monday
ฝัง
- เผยแพร่เมื่อ 11 ก.ค. 2024
- We are pleased to welcome Dorota back to the channel with a new instalment of VS Monday. On this episode, Dorota will be looking at using a drysuit for buoyancy control VS using a BC for buoyancy control
JUMP TO A CHAPTER:
0:00 Intro
2:47 How the drysuit is used
5:19 How much gas the drysuit contains
8:19 Complexity of Shape
10:44 Common issues of control
13:15 What's the solution?
17:52 Summary
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VIDEO CREDITS:
On screen: Dorota Czerny
Post Production by Nico Lurot
Music by DJ Williams Titled "awaken together" on TH-cam audio library
#ScubaDiving #BuoyancyControl #DrySuit
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Perfect, after being told I was doing it wrong for decade this is absolutely the safest, most comfortable and logical method of dry suit diving, even with an auto dump valve. Thank you so much👍
Just a fun little fact regarding feeling like a vacuumed piece of food. In the sous-vide cooking community, the 'water displacement' method is actually used to sort-of vacuum pack food, and it's exactly like what happens when you don't equalize the drysuit 😁
Thanks for this great video. Just completed my dry suit course and am happy to take what I’ve learned to the lakes in Germany
I only use my BC for buoyancy control. When diving with my Drysuit, which is 90% of the time, I just add a very minimum of air to stay warm, if I get colder going deeper I add a bit more but that’s it, my Drysuit is just here to keep me warm, my BC and lungs controls my buoyancy, while getting back to the surface I vent my Drysuit’s air.
That’s how I’ve been taught in my Padi Drysuit specialisation…
Po obejrzeniu paru odcinkow widze Dorote i klikam. Profesjonalnie, prosto i logicznie.
Really enjoyed the video despite of the fact that I knew exactly what will be discussed beforehand. Agree with all points 100%
Excellent!
Thank you so much. I just purchased a new Waterproof D7X Drysuit so I know already its going to feel like I'm learning how to dive again. hopefully I will find a good instructor like yourself and learn the right way sadly I've seen there aren't to many good instructors as when I first started diving, most only care more about the money then teaching to making sure you become a safer diver. its really a shame. Dive safe and keep doing what I see you love doing. Thank you Dorota. 😊
I just purchased the D7X Cordura. I am concerned about the sizing, especially around the chest since I have an athletic build. How do you like the way the suit fits? Does it stretch well?
Thank you, Dorota,
Great video. Thank you
Fantastic video 🥰🤿👌
Gracias
Great information please keep the videos and quality information coming.
Hye Sean, will do my best.. and will try to make it more frequent, too. Just some time/work/commitments management is needed :))))
clear and full of information good video!
Superb video! Very logical. You inspire confidence. Thanks for posting.
Very helpful!
Very good explanation, thank you! I'm new to drysuit diving and found this so helpful.
Great video! I just bought my first drysuit this week and I planned on controlling buoyancy with my BC for the reasons you stated :) Drysuit is only for comfort.
Thank you 🙏 very much.
New dry suit diver here . DUI .
Was worth it.
Excellent advice, thank you. I just purchased a drysuit and am using the BC as primary. I do need more practice though managing the drysuit experience.
excellent video!!!!!Thank you
most dry suits say in the manual " this is not a buoyancy device " ..
Wing for buoyancy , and just enough gas in the dry suit to take off the squeeze .. 👍🏽 manage both 👌🏽
After the first two minutes I was impatient to get a straight answer, after 19 minutes I was still hanging off every word, this is a brilliant discussion, thank you!! And I got my answer, keep doing what I've been doing. Phew. I'm too old to learn something new :)
"Certain agencies", haha 😀 Great video as usual, thanks!
Thanks! Glad it proves to be useful for some divers out there :)
A great video.
Great video 👌👌👌
A drysuite is.. water tight.... uuh most of the time. I'm dying here.
It took me ages to work this out by trial and error. Shame I didn’t see this video earlier. Totally agree with everything you say
hello Sarah, Thank you very much and I am sorry to hear that it was the "longer" path for you. But... you got the experience, and now you can definitely advise fellow divers from your OWN experience which is one of the most critical elements of being a competent and comfortable diver :)))
@@dorotaczerny6811 Absolutely.
I tell everyone less air in the drysuit is best. I've had that air in the boots, feet up. It's not nice. I've got a old compressed neoprene suit & a new trilaminate. I must say in the former is much easier to control postion in the water but it's so hard to get in & out of.
I once had the dump valve fall of my wing. The good thing is you can use your drysuit for buoyancy in a emergency situation. Thanks for the great videos
Great summary! One thing i was told that really suddenly made me think about the effects of volume vs depth was:
Draw a square on a piece of paper (any size will do)
Draw a line that splits that square into two equal halves, enclosing two equal areas.
One of those areas is equivalent to the change in gas volume during a decent from the surface to just 10m of water depth
The other area is equiavlent to the change in gas volume during a decent from 10m depth to the bottom of the Marianas Trench, some 11 km deep
That should demonstrate how critical your gas control is during the first and last stages of any dive!
Hey Max, that is a cool comparison. And indeed very important. Many divers would feel safe because they are shallow, but in fact, the first 10 meters are the most impactful, and any sudden buoyancy changes if not under control are really huge (not even mentioning gas explanation in your lungs if you would hold your breath). Thus beginner dive training is so critical, and it always concerns me if I see poorly trained beginners who do not really understand some basic concepts, and are unaware of the risks that can be very easily avoided with good education
Could you please explain that with some numbers? A descent from the surface to 10m is a doubling of pressure from 1 to 2 atm. From 10m to 11,000m is an increase from 2 atm to approx 1,101 atm. A factor 550, right? Am I misunderstanding your diagram description?
@@Yggdrasil42 Let's say you have a volume of 10 liters at the surface. At 10 meters it will be 5 liters. Now you can go as deep as you want it will never be under 0. So yes the first 10 meters you have half of your volume "used". Another way of putting it is to divide those 10 liters by 2 each time you double the pressure : 10/2= 5 (as we saw), 5/2=2,5 (so those 20 meters more depth are also important, but less), 2,5/2=1,25, 1,25/2= 0,625, 0,625/2=0,3125 , and so on... You see that at the end, going deeper change the pressure but not so much the volume left from the surface (even if it is half the volume each time you double the pressure, at the end you double a very small volume)
Damned interesting video. 4:10 says it. Drysuit when submerged is your main buoyancy with the BC the main buoyancy at the surface. If you are in danger of burping air out of your suit at depth and drastically affecting your neutral buoyancy, you are very overweighted. (11:05). Sort out your weight in the same way as you would when wetsuit diving: head up at the surface with your eyes at the waterline with all the air or nearly all the air dumped and exhale to submerge feet first. Under the surface, there is no need to use the BC: it becomes redundancy. Of course, you need to master the drysuit. Carrying on using the wing/BC is putting off mastering the drysuit - air migration and using it to advantage is part of that mastery.
Having a dry suit is also a backup in the very rare case of complete BC failure (which can be managed by oral inflation but let's assume that also isnt working). We did try to inflate and deflate both the BC and the dry suit to prove that the exhaust valves have more capacity than inlet valves. But I don't recall discussing the case of BC failure (or drysuit failure) in my Fundies class, so would be interesting to learn how to deal with that kind of scenario. Thanks for great content!
hey there, management of those failures is not of the Fundamentals course. Our Rec 1 (open water equivalent) teaches students with BCD failures, and drysuit primer with drysuit failures - as putting all into a Fundamentals course is not really practical and would make the course really "busy" with knowledge. But agreed on the importance of the abilities to deal with those emergencies in a efficient way.
Very good video! I'm waiting for the next. Here, just one comment: for my experience, the real question is not decide which of the 2 devices must be used as primary bounyancy device, but it is: "how much is it the correct amount of weight when I'm diving with the drysuite. Once, the diver find its aswer to that question, then it will becomes natural use its drysuite only for warming purposes.
one of the planned videos will be the concept of GUE's Balanced Rig and what does it mean to us to be properly weighted. I hope this would help with some weighting questions :)
Has the video on balanced rig been created yet?
Thank You so much for the vid but I could not find the video you mentioned that shows how to Ascend or Descend with a Drysuit! is it on this channel!?
I use wing as a primary but I tried the other method too but it proved to be extremely uncomfortable as the gas would keep shifting in the suit and upsetting my trim. I think the argument that people make that it's "diffcult" to use two bouyancy devices at once comes from having the auto dump valve all the way open. When the diver attempts to dump some gas from the BC to adjust the buoyancy the suit automatically dumps any gas that collects in the arm, even when the amount in the suit is just fine. That not only causes a more radical change of buoyancy than expected but also provides less than optimal amount of gas in the suit, which causes the diver to add the amount of gas that escaped to the suit after dumping from the BC. The solution to that is to just dial the dump valve a couple clicks back and it is much easier to do exactly what you want underwater.
I'm a cold-water divemaster and tec-diver, from "THE organisation", and I've done all my dives in a dry-suit, using only that as my bouyancy control device, without any issues.
On the other hand, I've done quite a few dives, and are properly weighted in the water (just slightly negative to natural with empty drysuit and tanks).
So. I don't really agree with some of the points in the video, but I've also seen beginners do feet-first ascents... :)
I did my dry suit course with "that certain agency" when I had something like 15 dives and was of course told to use the dry suit only for a boyancy control. After 10 dives when I just blindly followed that recommendation which I got during my course - and constantly having most of the difficulties Dorota is describing in this video - I started experimenting with that and started adding gas to my wing as well. Improvement was immediate and significant. Happy end: when I had about 40 dives I met a GUE diver, signed up for Fundies and learned how to do it properly 🤣
Hey Johan :) thanks for the feedback! There is one key statement in your comment "properly weighted", and there are definitely divers who do dives without getting into troubles. I am trying to explain why GUE would do things in a certain way and what the disadvantages may be on both sides. But appreciating your input here! :)
@@knutholm487 I'm a new diver (SSI) and I've been told to use only the dry suit as bc. I too found it difficult at first but after my 6th dive i got the hang of it.
But I think you should do what fits you and makes you a safe diver! I'd rather dive with someone that has the hang of it their way rather someone that is out of their depths and still trying to "do it right".
It all boils down to practice, practice and pracitce. Finding other ways to keep you safe under water is good, but i still feel that having less to think about/doing while diving is a plus.
@@alexg4684 indeed, and it will come over time. It is important being in water often and building your muscle memory, so all what you are doing gets fully automated and comes without thinking.
It is important though to get your technique right (sooner the better), because getting rid of some of the old bad habbits is always difficult (that's valid in general, doesn't apply on diving only).
I wish you lot of fun on your journey and happy diving!
I use to see a lot of divers put rings of cut car tire tubes just around the knee area for 2 reasons. 1=keeps the air/gas from traveling down your leg & 2,=keeps the knees protected from abrasions. I started out using both & tried using only the dry suit & ended up using mostly just the winged BC. New Jersey wreck diving with water temps between 42F in early spring to 50F in by late summer. Down to 145' you feel some squeeze but nothing discomforting.
Hey ted :)) mhm.. that is an interesting concept - those tire rubber rings (?) :)))). I need to say they are really unnecessary when the technique of releasing gas from the suit is properly mastered and to be honest, it can become a hindrance. From my perspective, sooner than later there will be some gas travelling up the boots (regardless of how tight the rubber over your needs will be) and then in case you end up legs up, it will be nearly impossible to get rid of the gas form the boots on time (during an ascend for example) and it will generate the exact problem that they try to avoid. And additionally restricting (even a bit) blood flow to extremities will cause the feet to get much colder much quicker. Better to invest time in practice than cutting those rings from tires IMHO :))
@@dorotaczerny7496 I guess. I never used them but have seen them worn by a few. One thing I didn't mention is, I use ankle weights. I'm not sure it makes much of a difference. Happy diving & stay safe.
What's there to see in moderate climates? The best underwater landscapes! Like coral reefs are cool but in Ireland it's all about amazing pinnacles, arches, walls, caves. There's a lot to see in cold water
I tend to use my BC for gross buoyancy adjustments and my drysuit for minor adjustments.
After you do a bunch of dives it all becomes second nature. Just like when you drive a car you don't have to consciously think I need to stop...I'm going to press on the brake with my foot. You just think I need to stop now and your foot hits the brake without thinking. Raising your arm and/or inflator hose to dump air or hit a button to add air to either just happens when you know you need to adjust your buoyancy to stay neutral.
True. The more you dive, the better you get! It can’t be 100% taught, past a certain point it’s experience, muscle memory and instinct 💯
The underlying practical message given in this video makes sense. The scientific backing for some of the message feels weak. Whether ‘gas’ is in the dry suit or the BC one will use the SAME amount to be neutrally buoyant at the same depth - one will not have more in the dry suit than one would have in a BC/ wing. Gases will then escape very quickly from any location IF there is a significant pressure gradient in the right direction (think of puncturing a tire) - I do not ‘buy’ the argument about having ‘a long way to travel’ (from boots) or taking longer out of undergarments. However, what does make sense is a) that the valve capacity from a BC inflator mechanism is higher than a dry suit exhaust valve, and b) that the nature of the dry suit exhaust valve on the left shoulder makes it more difficult (compared with holding a BC inflator hose above your head or pulling a BC dump valve which is at the high point of the BC when horizontal) to ensure that it is fully and continually open - because if the valve is pointed the wrong way (down), or is below where the gas is (such as in the boots) the valve will be closed because the pressure gradient is in the wrong direction. The combination of these two means that getting the same exhaust flow from a dry suit is more challenging than with a BC/ wing.
hey there, of course, gas will escape due to a difference in pressures, and yes - I may simplify some concepts to make them a bit less scientific, or more understandable. The problem (challenge) is still if the gas gets trapped - too big drysuit that creates folds holding gas in, undergarment materials trapping gas, or anything that restricts gas flow. And I guess we are in the end talking about the same concept :) :)
So you have 2 buoyancy devices. One is designed specifically to give fine control over how much gas it contains, keeps it in a single controlled place and allows rapid dump from one of multiple valves regardless of your attitude in the water. The other does none of these. I'm with Dorota on which one should be the primary.
So it's OK to break trim to vent gas from your drysuit? Maybe it's a question of how much, but I can't help thinking my dump valve isn't properly positioned. It feels like I have to go almost vertical to vent gas from my suit.
hey there, of course, it is ok to break your trim to vent gas !!! Please check the recent Q&A live stream we did - as this question was asked there! Your challenge may be indeed the valve positioning (some drysuits have not in an optimal position); another one may be that your undergarment holds gas more than others (Thinsulate thick undergarments have this tendency); or you may not position your body in the best position. There are some nuances how you position your hand when you dump gas. Try to flex your elbow; lift it up, get your fist towards your chest (do not extend the arm fully so the palm of your hand is up) - you can add a pumping movement with the arm (by flexing the elbow) trying to squeeze the gas out...as one of the tricks that may help :)))
hey there, sorry to miss this one - yes, of course, you have to break trim to get the gas out of the suit sometimes. So no problem with it :) :)
Anyone know where the video is for managing ascent with a drysuit? I struggle with this at times.
th-cam.com/video/BwOzZS_Hhhk/w-d-xo.html
When you dive with a rebreather, do you still use the wing for most of the buoyancy?
Hey there,, yes - the same concept. Rebreather does not really change the concept, even though you add yet another element that will influence your buoyancy - the counter lungs. But they should not be used as buoyancy compensator (device) as they should contain only optimal loop volume (allowing for comfortable breathing), and the buoyancy is controlled with a wing as usual. And here you really need to master natural buoyancy, as it is much harder to "cheat" a bit with your breathing control :)))
@@dorotaczerny6811 The big difference between diving a rebreather and diving open circuit could be the difference in change of buoyancy over the dive between the 2 configurations due to the volume (mass) of gas consumed in Open Circuit vs rebreather. Let me preface this by stating that I am not a rebreather diver but can maybe understand Stefan's question because I dive different open circuit configurations and I notice that I use the drysuit and wing differently in different configurations. Case 1: Cold water, single steel 100cuft cylinder I start the dive pretty much neutrally buoyant at the surface and, during the dive, by the time I have removed the squeeze, I am once again neutrally buoyant and do not need to use the wing at all. Case 2: Cold water, double steel 100cuft cylinders, which potentially change buoyancy by as much as 16lbs from full to empty (I know, they will never be empty, but let's approximate). For this I must start the dive negatively buoyant (or I can't hold a final deco stop at 20ft by the time the cylinders are "empty") so I already have gas in the wing at the start of the dive. In this case, since both the wing and the suit compress, I need to add gas to both on descent, one to remove squeeze and the other to restore neutral buoyancy. My conclusion is that if your buoyancy (due to gas consumption) does not change much over the course of the dive then simply removing squeeze restores neutral buoyancy, but if you need to plan for greater buoyancy change during the dive due to gas consumption then drysuit alone will not be sufficient and is ill-advised.
I would be interested in feedback from others, do you find that different equipment configurations cause you to use your drysuit/wing differently?
hey there, yes - definitely and even more so in my case, as my RB is very heavy and I need quite some lift and the BC is the one for me to get the most buoyancy.
@@grahambirch3715 what you describe is a bit of what we call in GUE a "balanced rig" so a piece of kit that is properly weighted for both the beginning of the dive (being heaviest due to gas) and the end of the dive and thus being lightest (due to gas used). For me, the way I use the drysuit/wing is not really related to the configuration (type of gear) but the temperature, as I would tend to add more gas when the water is getting colder. Of course, depending on the weight distribution and inability to adjust it (for me for example a GUE configurated RB which is heavy regardless), I may add more gas to the suit to compensate for example heavier legs. But generally speaking, there is not so much difference for me.
My tank is about 4 kg heavier at the beginning of a dive. So technically I'm overweighted every time I get in the water. Though if not, I'd have trouble keeping my buoyancy on the safety stop.
I think that when you say "certain agencies" you should say THAT ONE agency we all know ^^
Hey Alvaro :)) Well, I try not to point specifically to any, as there are quite many training agencies. Sometimes (most of the time) individual instructors can make a huge difference in the level of training (in one way or another), but still, the training agency standards would need to be used even if they allow for some flexibility. What I really appreciate with GUE is the standardization of training and the fact that instructors are teaching the same concepts while adding their own experience as a "proof of concept". So it is not about pointing who is right or wrong, but being able to demonstrate reasonable arguments why one does things in a certain way.
@@dorotaczerny6811 I'm sorry but I don't see it that way. The it's the instructor, not the agency is plain wrong. If you ever cross some instructor from THAT AGENCY who doesn't plain suck, ask them where they got their training. I bet my right arm they will say from another agency or another instructor from another agency.
@@Agranell :) maybe I did not express this correctly - it can be both (agency and/or instructor), but what is a weakness in many in my opinion is that their standards allow for quite some flexibility which often allows for more "individualised" approaches to training. For me, what I really found attractive when I switched to GUE was the concept of standardization (on various levels) which allows for consistency in training.
@@dorotaczerny6811 quality in training can be assured without standarisation. But there's an actual need of quality to be able to offer it. If someone can reach instructor or instructor trainer af an avency without even knowing how to mantain propper neutral buoyancy and count with good propulsion techniques (and a very long list of other things) that agency will never be able to offer quality, standarizing or not. Thanks for your responses ans time
I understand the reasoning but this isn’t practical for me. As it is, if im properly weighted then there isn’t all that much room in my suit so that the gas needed to keep me warm/ squeeze off is all I need to get neutral in good trim. Extra gas in the wing or suit just isn’t needed. Guess I just got lucky with my sizing. 🤷♂️
This was a strange video.
Firstly «Why dive in cold water. There's nothing to see, and the visibility is poor.».
What???
In colder waters you have a different eco-system than in tropical waters, but it’s teeming with life!
Huge kelp forests, huge variety of bottom dwelling life, huge variety of fish, crayfish, non vertebrae's like anemones, cold water corals, and crystal clear waters during autumn/winter when photosynthetic algae growth is surpressed.
Cold waters tends to hold more nutrients than warmer waters, hence more life. (That's why big whales (and pelagic fish) migrate to arctic and ant-arctic waters to feed outside mating and calving season).
Then to buoyancy and dry suits.
Apart from the odd holiday wetsuit-dive at tropical latitudes, I have exclusively dived with drysuits for the last 35 years. Both with single tank, double tank, and sidemount configurations.
I (and everyone I know) only use the drysuit itself for buoyancy control. Wing or vest BCDs are only used at the surface when you first jump in, and when you resurface.
Properly weghted, and after compensating for suit-squeeze as you descend, only minute amounts of air (in or out) of the drysuit is neccessary to control buoyancy. Fine tuning is done with breath control. To release air, you just lift your left shoulder/arm slightly, and release a minor amount of air. The sensitivity of the shoukder valve can be adjusted by rotating it.
You swim horizontally and use buoyancy to descend or ascend, you don’t aim your body downwards when you descend. If you did, all air in the suit would end up in your feet. However, even If you did end up with all air in the legs of your drysuit, it is not particularly difficult to right yourself again using your feet and flippers.
If you end up with a lot of air "sloshing around" in your drysuit, you are either heavily over-weighted, have a drysuit that is way to big for you, or both.
The notion of air blasting out of your neck seal when twisting your head, is completely bizarre to me. Then either your neck-seal has an extremely poor fit, or you carry 100 lbs of lead and have inflated your drysuit like a balloon.
To dive with air in both your BCD and drysuit will only complicate things. If you need air in your BCD for buoyancy control, you are too heavy!
(TEC-divers carry a lot of extra tanks and heavy equipment, so they MAY need to add a bit of air in their wing. But I'm not a TEC-diver, so I wouldn't know).
Isn't this why an exhaust valve is fitted to your drysuit?
Thank you so much for confirming my notion that GUE is giving out wrong information. I am a cold water instructor who has been teaching using your drysuit for your buoyancy for over 10 years and with a little practice and proper weighting my students have been able to achieve perfect neutral buoyancy using dry suit only. Maybe a little more research into what you talk about before you talk about it would be a better way to inform people.
PADI Drysuit course…. Don’t bother. The videos and E learning are from the 1980’s 😂
I can spare you some money or a shed so you don't have to share your space with a music school is that ok
I'm surprised you didn't promote Halcyon gaiters to prevent air moving its way down to your legs.
Why the bitterness?
@@GUEdivers Negative attitude is unwarranted. Critique is part of going forward.
@@scubaclient355 All for criticism!!! Could you please explain what the criticism was? Because "I'm surprised you didn't promote Halcyon gaiters to prevent air moving its way down to your legs"... Failing to see the criticism there.. Please do explain though!
@@GUEdivers Learn to read English. Next time you make a video use cue cards and rehearse your subject. You left out information.
@@scubaclient355 wow... no need for hostility such as "learn to read English" dear sir. We would love to know what in formation we have left out and always invite intelligent discourse. But minus the hostility please.