help with drysuit buoyancy calculation

[orange_diver]

i'm trying to figure out how big a wing i need to dive my drysuit and a single steel faber LP. i don't have one currently but will be purchasing a SS bp/w with hog harness. this is for socal ocean dives. i'd love to be able to get away with a 30# wing, but think i may need 40#.

i've read all the posts, thank you especially to Tobin and someone else who posted an excel spreadsheet and the one peice of info i'm missing is this:

how much buoyancy does my dui CLXse (shoulder entry CLX450) and wheezle extreme undergarment inherently have that i would have to compensate for?

i was hoping people could weigh in with their experiences with the same or like materials, i.e. trilaminate suits and 200 - 400g thinsulate garments...

thank you all in advance.

 

[SteveAD]

I consider anything under 40# lift to be a purely warm water BC, unless you are a very tiny person.

 

[orange_diver]

i'm 6'1" 185.

I consider anything under 40# lift to be a purely warm water BC, unless you are a very tiny person.

 

[Scared Silly]

There is only one way to get the correct information. Put your suit on and go hop in a pool and see how much weight it take for you to sink. Then you can do the calculation properly.

Now just to show you how a difference there is what you think and reality. I did this test last month. I was figuring that it would be in 20lb range. In reality it was around 12lbs.

 

[Scared Silly]

I consider anything under 40# lift to be a purely warm water BC, unless you are a very tiny person.

Hmm, I can dive wet or dry and a single steel or al and only need a 30# wing with my BP. And I am 6' and 165lbs. Guess I am a tiny person . Of course if you are talking BCDs with all kinds of fluff on them then you might need more lead to sink it, which means an bigger bladder, which means more lead, ...

 

[dannobee]

I consider anything under 40# lift to be a purely warm water BC, unless you are a very tiny person.

If he's diving with a drysuit, there's enough bouyancy there to obviate the need for a big lift BC. I dive dry with thick underwear, with a few different fabers, including that heavy HP100, and I use a 40 lb wing. I've concluded that I don't need one with that much lift. My next single rig will probably be in the 30 lb range.

 

[TeddyDiver]

i'm trying to figure out how big a wing i need to dive my drysuit and a single steel faber LP. i don't have one currently but will be purchasing a SS bp/w with hog harness. this is for socal ocean dives. i'd love to be able to get away with a 30# wing, but think i may need 40#.
i was hoping people could weigh in with their experiences with the same or like materials, i.e. trilaminate suits and 200 - 400g thinsulate garments...
thank you all in advance.

It more or kess depends of the thickness of your ungergarment and how "tight" (volume of the air inside DS) you use it. DS you have is trilam so it won't compress, just do what Scared Silly said
Someone with neoprene DS (like me) have to account also neoprene compression at depth.

 

[orange_diver]

There is only one way to get the correct information. Put your suit on and go hop in a pool and see how much weight it take for you to sink. Then you can do the calculation properly.

Now just to show you how a difference there is what you think and reality. I did this test last month. I was figuring that it would be in 20lb range. In reality it was around 12lbs.

let's say i need 15 lb in the pool, how does that correlate to lb needed in the ocean given that salt affects buoyancy? is there a simple calculation, i.e. add 10%?

thx for all replies everybody...

 

[TeddyDiver]

let's say i need 15 lb in the pool, how does that correlate to lb needed in the ocean given that salt affects buoyancy? is there a simple calculation, i.e. add 10%?

No need to if you are properly weighted. For weights you add some (3-4kg or 5-9lbs)
when going to ocean from fresh water, but with bouyancy such compensation is not needed.
To be accurate in the ocean you need less bouyancy capacity compared to fresh water.

 

[dannobee]

let's say i need 15 lb in the pool, how does that correlate to lb needed in the ocean given that salt affects buoyancy? is there a simple calculation, i.e. add 10%?

thx for all replies everybody...

The simple calculation is to multiply your total weight of everything by 0.0256. That is how much lead you'll need to add when going from fresh to salt water.