safety of bp/w & more buouyancy questions

1) Do wings ever undergo rupture, or get a significant hole while diving, making it problematic to return to the surface? For some reason, I am under the impression that the standard vest type bc's are indestructable and I am curious about the integrity/reliability of the wing. I need a little reassuance.
2) If the wing I ordered has a 30 lb lift, how does that compare to the standard off the rack vest bc in terms of lift?
3) Finally, in a conversation I had with Tobin yesterday he noted that the only thing that loses buouyancy as you dive is your wet suit. Thus, suppose a given diver wore a 7 mm full suit and needed 18 lbs of wt to reach neutral buouyancy and then the same diver was to switch out to a thin dive skin and only need 3 lbs to acheive neutral buouyancy. Does not this mean that as he descends and the 7 mm suit loses buouancy that the diver will find himself realtively overweighted at the bottom of his dive compared to the those dives he does in the lighter suit? Would he not find that in the 7 mm suit he needs to partially inflate his bc/wing at depths, compared to when in the lighter suit?

1. A BC is definately not indestructable - they can be punctured just like a wing. As for durablity probably the same between a good quality BC and wing.

2. My large BC has 51 lbs of lift. My girlfriends small has 44 lbs of lift.

3. Yes as your suit compresses you will lose some buoyancy - this should not be a problem. Also as you descend the air in your BC also compresses so you have to add air to maintain netural buoyancy anyway. Thats why you need to dump on the way up as the air expands it provides more and more lift - if you don't dump it you will go faster and faster.

louis:

1) Do wings ever undergo rupture, or get a significant hole while diving, making it problematic to return to the surface? For some reason, I am under the impression that the standard vest type bc's are indestructable and I am curious about the integrity/reliability of the wing. I need a little reassuance.
2) If the wing I ordered has a 30 lb lift, how does that compare to the standard off the rack vest bc in terms of lift?
3) Finally, in a conversation I had with Tobin yesterday he noted that the only thing that loses buouyancy as you dive is your wet suit. Thus, suppose a given diver wore a 7 mm full suit and needed 18 lbs of wt to reach neutral buouyancy and then the same diver was to switch out to a thin dive skin and only need 3 lbs to acheive neutral buouyancy. Does not this mean that as he descends and the 7 mm suit loses buouancy that the diver will find himself realtively overweighted at the bottom of his dive compared to the those dives he does in the lighter suit? Would he not find that in the 7 mm suit he needs to partially inflate his bc/wing at depths, compared to when in the lighter suit?

Click to expand...

1 A wing is no more or less susceptable to a puncture, tear, or seam failure. Should that happen, you shouold be able to swim your rig to the surface. If you can't, you need to carry a redundent bouyancy device or be prepared to drop some weights.

2. I dive a wing rated for 30 lb. It is great for single tank warm and cool water diving. Except for small sized BCs, most have more lift than that. But it is usually excessive for recreational diving.

3. If a 7mm wetsuit requires you to add 20 lb to be neutral at the end of the dive, then compression should reduce its bouyancy down to about 5 lb at 100 ft. Your wing has to make up for that 15 lb to make you neutral. Also, at the beginning of a dive your wing also has to make of for the 4 or 5 lb of gas you will consume. So early in a dive to 100 ft with that 7mm suit, you'll need almost 20 lb of lift to be neutral. So the 30 lb wing should do the job. I've seen 2 piece 7mm suits that took 30 lb of lead to compensate for their bouyancy. That rig would use up almost 23 lb of lift. Still within the capacity of a 30 lb wing but getting close but still workable even down to 130 ft. If I were planning on diving that kind of rig, I might prefer the cushion of a 36 or 40 lb wing.

My 3mm suit is only about 7 lb bouyant which should compress to about 2 lb at 100 ft so the wing only need to provide 7 (2 for the suit + 5 for the gas) of lift on a 100 ft dive.

One thing to note is that the material wings are made of come in a wide variety of material, however most of it is protected by your body and tank, so it has imo less of a chance to snag on something that could puncture it.

In general, the wing manufacturers make their products to at least the same standard as most rec BCs, including punture resistance. As kidspot pointed out, it's probably less likely that you'd puncture a wing than a jacket style BC, where the bladder wraps around you and is more exposed...I wonder how many people have accidentally punctured the front of their BC with dive knifes, for example?

Your question about buoyancy and the thickness of wetsuits is perceptive and has been answered well. A couple of added points; one, wetsuit compression explains why it's usually easier to control buoyancy in a thinner wetsuit; you need less weight to get down and stay neutral at the end of your dive (when you're near the surface) and consequently you need less air in your BC at depth. That means you have less change in buoyancy with slight changes in depth. (Any air in the BC will expand and compress depending on your depth, accelerating buoyancy changes) Two, most standard BCs have a fair amount of positive buoyancy and compressability, and this is a nice advantage to a BP/W set up that has negative buoyancy and very little compressable material. The more stuff you have that compresses at depth, the more weight you have to wear, and more adjustment it takes to stay neutral with slight depth changes.

Loius,
A profile would help us answer this... are you diving warm or cold? Steel tanks or Alum.... most people who are diving BP&W's are DIR or Hog so they are aiming for a balanced rig.... just enough weight - you can swim up if you needed to in case of a wing failure. Which is rare

Mattboy, you are right on target about the difference in wet suit thickness. I did my OW cert in Hawaii wearing a 3 mil suit. When I visited my sister in San Diego a month later I had to wear a 7 mil suit. What a difference! The buoyancy changes were much more dramatic in the 7 mil, especially closer to the surface. I had no buoyancy problems at depth, but had difficulty slowing my ascent rate. Of course, it didn't help that I grabbed my snorkel instead of my inflator hose when I first went to dump air from the BC.

as far as my diver profile: I am going to be mainly diving in the Carribean, but certainly if I go elsewhere it will only be warm water. I ordered a bp/w from DeepSeaSupply a few days ago and imagine it will arrive in a couple of days. (30 lb wing) I am getting a Hogarthian set up and will probably be diving in a 5 mm farmer john suit.

I also thought about the safety of the BP/W setup (in my case due to not having easily ditchable weights), but it was pointed out to me that you should be able to swim to the surface with all your gear on even if the BC is punctured or destroyed somehow. I've never tried it, but I imagine such a swim should not be a problem.

Wings are just a type of BC. The construction techniques used to make wings, are the very same ones used to make BC's

You can purchase a vest BC that's of single layer construction, and you can purchase a vest that has a sewn outer layer with a welded inner bladder.

The key difference is that in most vests one cannot access the inner bladder.



Tobin