Max. operating depths for wings ?

[PvtStash]

Hellohello , I've been looking into deeper/technical diving and have recently been thinking of potential equiptment limitations and the (un)safety therein...

For example... a couple of weeks ago I did my deepest dive to date... 101' ... I enjoyed it immensely but was Very aware of my ever-compressing wetsuit and its diminishing buoyancy characteristics as I intermittently added air to my Apeks BC (standard 35lbs wing)... (wetsuit is the Bare arctic combo 7mm full w/ 7mm shorty over it, 14mm core!)

After the dive and earlier this week I've been pondering... thinking that At Some Point/Depth... me, my gear, tank and BC will be More than a match for my BC's lift capability... and I am curious as to what that depth may be... , I can imagine the horror... say at 180'... and filling my BC but NOT gaining any lift! ... I'm not sure at what point/depth is that "point of no return" (at least without swimming/finning) as it will vary depending on exposure protection... which is another factor in itself... Those with little money for High Dollar exposure protection are more prone to this adverse potentiallity as the buoyancy characteristics of the vastly cheaper wetsuit is So variable with depth.

My tank alone is 50-60lbs... how deep do you reckon I can go an still get positive when ready to ascend ?

 

[wunat]

how deep do you reckon I can go an still get positive when ready to ascend ?

Do you actually add air into your BC to ascent?

 

[PvtStash]

well not exactly... first I add to my lungs... but should they not be sufficient then Yes... I do... is this Wrong/Bad ?

 

[PvtStash]

did you actually have any kind of non-flippant/egoist answer to my query? or did you merely wish to feel special ?

 

[Cave Diver]

Hellohello , I've been looking into deeper/technical diving and have recently been thinking of potential equiptment limitations and the (un)safety therein...

For example... a couple of weeks ago I did my deepest dive to date... 101' ... I enjoyed it immensely but was Very aware of my ever-compressing wetsuit and its diminishing buoyancy characteristics as I intermittently added air to my Apeks BC (standard 35lbs wing)... (wetsuit is the Bare arctic combo 7mm full w/ 7mm shorty over it, 14mm core!)

After the dive and earlier this week I've been pondering... thinking that At Some Point/Depth... me, my gear, tank and BC will be More than a match for my BC's lift capability... and I am curious as to what that depth may be... , I can imagine the horror... say at 180'... and filling my BC but NOT gaining any lift! ... I'm not sure at what point/depth is that "point of no return" (at least without swimming/finning) as it will vary depending on exposure protection... which is another factor in itself... Those with little money for High Dollar exposure protection are more prone to this adverse potentiallity as the buoyancy characteristics of the vastly cheaper wetsuit is So variable with depth.

My tank alone is 50-60lbs... how deep do you reckon I can go an still get positive when ready to ascend ?

With all due respect, if you're asking questions like this you are nowhere near ready to be looking into technical diving.

It's good that you're considering safety, but you reasoning is flawed.

Of course you have to add air as you descend. Was it not covered in your BOW class that volume diminishes as you descend? At 99' you're at 4 ATM and the volume of gas in your wing has decreased to 1/4 of it's original amount.

Also, you should be venting air from your BC as you ascend, not adding air to ascend. Same principle, air expands as you go up, increasing your lift and you'll find yourself rocketing to the surface in an uncontrolled ascent.

In addition, the weight of your tank is not relevant. The bouyancy characterstic is and your tank should become more bouyant as you breathe it down.

If you do not have these basics concepts down yet, I would strongly suggest you limit your diving until you fully understand them. Please do not think of doing any extended range or technical diving without a full understanding of the consequences. There are some very good threads on the board explaining some of these concepts but internet learning is no replacement for hands on experience with a qualified instructor. There are several excellent ones here on the board as well.

There is a saying my dive team uses often: "You don't know what you don't know and what you don't know can kill you."

 

[Cave Diver]

well not exactly... first I add to my lungs... but should they not be sufficient then Yes... I do... is this Wrong/Bad ?

If taking a deep breath is not sufficient to cause you to start to ascend then you are not neutrally bouyant to begin with. You should be able to hover in place in the water column while not swimming while breathing normally. A deep exhale would cause you to sink, a deep inhale would cause you to rise. Failure to exhale as you continue your ascent may result in a lung over expansion injury and failure to vent expanding air from your BCD may result in an uncontrolled ascent.

 

[PvtStash]

yes I know how pressure affects a given volume of gas... and those other basics... now about what I Actually Asked ?

 

[Cave Diver]

yes I know how pressure affects a given volume of gas... and those other basics... now about what I Actually Asked ?

I answered your question with those very basics, perhaps you should read them a bit closer.

It takes a given volume of gas in your wing to provide a given amount of lift. If you have sufficient lift to float you on the surface, you should have sufficient lift at depth.

The amount of lift you require doesn't change with depth, except with minor suit compression.

Additionally, since your tank will become more bouyant towards the end of the dive, your lift requirements should actually decrease at that point.

 

[Cave Diver]

Oh and in regard to your exposure protection question, your wing should provide sufficient lift to overcome the negative shift due to suit compression at depth. At 100' a wetsuit is providing little to no bouyancy anyway so that shouldn't be a factor.

 

[Cave Diver]

yes I know how pressure affects a given volume of gas... and those other basics... now about what I Actually Asked ?

My tank alone is 50-60lbs... how deep do you reckon I can go an still get positive when ready to ascend ?

If your rig will float you at the surface, you can go as deep as you wish and you should still be able to get positive.

Whether or not you'll have the ability when you're narked out of your mind or an emergency arises will be another question entirely.

If you dont like this response, perhaps you'll find the answer you seek here: http://www.scubaboard.com/forums/3453645-post6.html