Redundant Buoyancy

[DogDiver]

Your redundant buoyancy is called a dry suit.

 

[Nemrod]

I will be diving a new bp/w with a stainless steel back plate. By my calculations, I will not need to add any removable weight in order to be negative at any depth. The negative of this is that if for some reason there is a catastrophic BC failure, I wont be able to become positive by dumping weights.

Now the total kit is probably about 15lbs negative. The buoyancy of the wetsuit will offset some of that unless it’s fully compressed. Let’s assume it’s a best case scenario and I can swim up to the surface. I’m now still about 6 lbs negative if I’m wearing a 3mm full. I don’t know how hard it is to tread water in those conditions.

Should I be carrying a safety sausage or another flotation aid? Or is my buddy a sufficient source of redundancy.

If you mean that you are 15 pounds negative in the water with the intended rubber blubber (exposure suit) and aluminum 80 then something is not right. But if this is true then you need to move to an aluminum plate. I think your calculations are wrong and the entire system (diver, suit, tanks, equipment, plate, regs etc.) including you is not 15 pounds negative.

I do not agree with most on this forum, I believe in jettison-able weight and with that weight jettisoned you should be at least a few pounds positive. You need to be able to establish positive buoyancy in any situation. All of the weight carried does not need to be jettison-able, only enough to establish positive buoyancy. If you cannot do that with a steel plate then you should go to an aluminum plate.

N

 

[AdivingBel]

---

 

[Divectionist]

I am going out today to test the wetsuit setup (it will be 5mm+2.5mm hooded vest) with my new 10.5l steel tank (buoyancy specs here are different from the US tanks, they are a bit more negative), which is probably a good simulator of how the above weights feel in just a 3mm suit in your scenario.

At this shore dive I can only go to 10m but the purpose is to see how heavy I feel with the steel tank so I'll swim the rig up and will report back here to give you one more data point.

Alrighty, definitely a few lbs negative as I need a few puffs of air at 5m to be neutral, I may pick up an AL plate for summer diving with this steel tank - but the news that concern you are that it is not at all difficult to swim it up, so you should be fine. Consider a lighter bp/w setup if you are concerned.

 

[Kharon]

After a near fatality, I wear a good quallity snorkeling vest under my harness and carry two fairly large SMB's. My solo training was big on redundancy for everything except buoyancy. When I needed it I didn't have it. I will in the future.

 

[tmassey]

After a near fatality, I wear a good quallity snorkeling vest under my harness and carry two fairly large SMB's. My solo training was big on redundancy for everything except buoyancy. When I needed it I didn't have it. I will in the future.

Interesting solution! A few questions: have you tested this? How does it work in practice? Are there any downsides to adding this that you've found?

And have you written up that near-fatality? I'd love to know more details about what led you in this direction.

Thank you for the ideas!

 

[FreeFlyFreak]

Do a proper weight check with all equipment you intend to use. It is the only way to know for sure.

I find it almost impossible to believe that you will be 15lbs negative.

For your reference, I am 6' tall 185-195lbs depending on the day.
With a 3mm full wet, a steel backplate and accessories about 5lbs, I wear 7-8 lbs of lead to be neutral at 10ft with 500 psi in an AL80.

Once you get your total weight needed right, with a weight check. Then you think about where to locate it for proper trim and ditch ability and if you need to add redundant buoyancy.

 

[Divectionist]

After a near fatality, I wear a good quallity snorkeling vest under my harness and carry two fairly large SMB's. My solo training was big on redundancy for everything except buoyancy. When I needed it I didn't have it. I will in the future.

Glad you made it. Was that incident on doubles?