Ascending without BC's deflation / inflation

[TSandM]

Oh, Crowley, I'd love to see that! I have to say that I think the way I did my ascent on the Thistlegorm is the way it should be done . . . with a scooter!

 

[Den7]

Lets remember what the OP asked :

Quote:
I was just wondering if are there any instances when at a certain point in time during an ascent a diver ends up with a completely deflated BC and simply has to swim up? In fact, does anybody happen to know if it would be easier or harder to control your buoyancy by trying to swim up (thrust) your ascent having your BC totally deflated?

Quote:
Originally Posted by Charlie99
....................My advice to the OP is to learn how to use your BCD. Dumping all of the air out of your BCD before an ascent is just making a lot of work for yourself. The right way is to stay near neutral throughout the dive.

He was not advocating nor opposing the practice, just trying to get information about it.

Thank you Merxlin

Charlie99, I was looking for as much information as possible but not for instructions on how to use a BCD...

 

[Rich Keller]

I do not us a BC other then when I am on a dive boat that requires one. I started diving before they were invented and always thought they were just a waste of air. Every time you go up or down a few feet you need to add or dump air that would otherwise be used to extend your time underwater. When I do need to wear a BC I am weighted so I never have to use it during the dive. If you weight yourself so you are neutral buoyant at the surface at the beginning of the dive suit compression will leave you slightly negative at the bottom. At the end of the dive you may be slightly positive or still neutral depending on the type of tank you are using. Your local dive shop will not agree because this will not help him sell new equipment but it works.

 

[Rhone Man]

In the old days everyone used to swim up and swim down. These new fangled BCDs certainly made it easier, but their absence didn't stop anyone in days of yore.

 

[Den7]

I do not us a BC other then when I am on a dive boat that requires one. I started diving before they were invented and always thought they were just a waste of air. Every time you go up or down a few feet you need to add or dump air that would otherwise be used to extend your time underwater. When I do need to wear a BC I am weighted so I never have to use it during the dive. If you weight yourself so you are neutral buoyant at the surface at the beginning of the dive suit compression will leave you slightly negative at the bottom. At the end of the dive you may be slightly positive or still neutral depending on the type of tank you are using. Your local dive shop will not agree because this will not help him sell new equipment but it works.

interesting observation.. Yes, there were times when BCs were not used at all and people managed to dive anyway. How do you attach a tank when you do not use any BCs? Harness?

Does not wearing a BC create trouble doing your regular "hang" (safety stop)?

Dive shops may have nothing to do with the equipment selling (hire / rent) for cases when divers own everything (my case as well, except a tank and weights).

 

[herman]

interesting observation.. Yes, there were times when BCs were not used at all and people managed to dive anyway. How do you attach a tank when you do not use any BCs? Harness?

Does not wearing a BC create trouble doing your regular "hang" (safety stop)?

Dive shops may have nothing to do with the equipment selling (hire / rent) for cases when divers own everything (my case as well, except a tank and weights).

Simple harnesses or backplates were used to attach the tank, pretty much just like today just without the bladder.

What you are missing is that if properly weighted maintaining neutral buoyancy is not a big deal. Unless you are diving huge tanks, doubles or thick wetsuits, the amount of buoyancy shift (the thing the BC is supposed to "compensate" for) should be fairly mimimal- around 4 lbs for an 80 is easily managed if you are properly weighted and understand how to your lungs as your primary BC. It is not difficut or uncomfortable as some would have you believe. I dive no wing a lot and it's a skill I practice every chance I get, even when diving where a BC is reguired I never inflate it. Safety stops are no problem, I recently returned from a trip to Coz where I was doing 5+ minute stops, no air in my BC and was have no problems. The only time I touched my inflator that week was to blow up the wing while it was drying.

 

[Rich Keller]

You can attach the tank to a back pack with the BC removed, harness or back plate. Hanging at a decompression stop is not a problem. You can check out this site for tank bouancy when both full and empty. Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[fjpatrum]

I was just wondering if are there any instances when at a certain point in time during an ascent a diver ends up with a completely deflated BC and simply has to swim up? In fact, does anybody happen to know if it would be easier or harder to control your buoyancy by trying to swim up (thrust) your ascent having your BC totally deflated?

I haven't dived really deep but my BC is always deflated above 45 feet or so in cold water. In warm water that depth goes down to about 60-65 feet before I need any air in my BC.

I've never tried to ascend with air in my BC. At least not intentionally.

To answer the question, though, it is entirely dependent upon the diver and the configuration of exposure suit, BMI, gas remaining and several other issues.

 

[Den7]

Simple harnesses or backplates were used to attach the tank, pretty much just like today just without the bladder.

What you are missing is that if properly weighted maintaining neutral buoyancy is not a big deal. Unless you are diving huge tanks, doubles or thick wetsuits, the amount of buoyancy shift (the thing the BC is supposed to "compensate" for) should be fairly mimimal- around 4 lbs for an 80 is easily managed if you are properly weighted and understand how to your lungs as your primary BC. It is not difficut or uncomfortable as some would have you believe. I dive no wing a lot and it's a skill I practice every chance I get, even when diving where a BC is reguired I never inflate it. Safety stops are no problem, I recently returned from a trip to Coz where I was doing 5+ minute stops, no air in my BC and was have no problems. The only time I touched my inflator that week was to blow up the wing while it was drying.

That's exactly where I miss out I guess. I read it someone said somewhere here on these forums that those who dive dry or farmers John & Jane only suits and have just about 5 logged in dives are buoyancy Gods compare to "experienced" tropical divers with hundreds of logged dives.

 

[herman]

That's exactly where I miss out I guess. I read it someone said somewhere here on these forums that those who dive dry or farmers John & Jane only suits and have just about 5 logged in dives are buoyancy Gods compare to "experienced" tropical divers with hundreds of logged dives.

Dry suits and thick wetsuit are a lot more difficult to manage but that is an overstatement. Nobody with 5 dives is a buoyancy god in a drysuit...for that matter, no one with 100s of dives but only 5 in a drysuit has it mastered. I have seen divers with a lot of "experience" who have no clue what buoyancy or proper weighting is all about but then again there are plenty of warm water divers who are masters of buoyancy control. I dive the entire range from dry to no wetsuit at all and work on my skills on every dive. It's an ongoing process that I try to improve on with each dive.