New in N. Cal! - Question about BC

[Chavodel8en]

Hi everyone. This is a great board. I just got certified during the summer, and plan on doing some dives in Monterey soon guided by local DMs (if anyone has a burning desire to buddy a newbie from the Bay Area, let me know!) and hopefully get my AOW before it gets too cold.

I had a question about BCs. At some point I will want to buy a BC. I would plan to use it in Monterey and possibly on vacation in tropical places - just recreational diving, swimming w/ the fishies. I don't think I want to do a plate/wings. So the two part question is.

1) How much minimum lift should a BC have for me diving Monterey. I'm 5'9", 190 lb., would be using a 7MM two piece w/ hood (doubt I'll ever go dry) and I doubt I'll ever want to go too much lower than 100-120 feet down. On my OW dive I used 35 lb (!) of weight (and still had problems getting down) - hopefully I can drop a few pounds. Is 34 lb. of lift enough? (that's what I rented in the OW, but of course we never went below 60 ft)

2) Could you recommend a good jacket-style BC that can be used in Monterey AND is fairly compact for travel. Economy is nice too.

THANKS IN ADVANCE!!

 

[cnidae]

How come you've decided against the BP and wing setup?

 

[Karl_in_Calif]

Any back inflation B/C with a stated wing capacity that equals or exceeds the sum of your lead weights plus the negative buoyancy of your full tanks, plus flashlight, plus reg, plus camera etc should work.

The problem around here (SF Bay Area) is that a lot of the popular jacket B/Cs are really East Coast designs not meant for the West Coast.

In your case, 35 lbs of lead (due to the double layering of your 7mm overlap wetsuit -- ugh!) plus 1 lb for the reg, plus 2 lbs for the light, plus 6 lbs for steel tanks, would require about 45 lbs of buoyancy in your wing.

Zeagle is the only brand that makes B/C wings large enough to handle all of that, that I know of.

You would be better off with a drysuit. Then you could drop your weight down to about 28 to 30 lbs.

 

[Karl_in_Calif]

cnidae once bubbled...
How come you've decided against the BP and wing setup?

...Possibly because he does not want to lug a backplate around?

 

[bwerb]

Karl_in_Calif once bubbled...
The problem around here (SF Bay Area) is that a lot of the popular jacket B/Cs are really East Coast designs not meant for the West Coast.

In your case, 35 lbs of lead (due to the double layering of your 7mm overlap wetsuit -- ugh!) plus 1 lb for the reg, plus 2 lbs for the light, plus 6 lbs for steel tanks, would require about 45 lbs of buoyancy in your wing.

Zeagle is the only brand that makes B/Cs large enough to handle all of that, that I know of.

Uh...mind explaining your understanding of the East Coast vs. West Coast B/C thing...methinks perhaps there is some confusion here.

Second...no no no...wing bouyancy does NOT need to be a function of your dry land weight. A BC should be able to have enough bouyancy to support a full tank on the surface...in other words, when you take your BC off, it should float on the surface without submerging. Weight intergration needs to be taken into account if used but you won't need the 45lbs bouyancy indicated here...heck a set of steel doubles on a 6lb steel backplate and cannister light easily floats with a 55lb wing.

The weight that you wear...35lbs in this case...is added to offset the inherent bouyancy of you and your exposure protection. If you are correctly weighted, a very small amount of air in your bladder will move you up rapidly.

Chavodel8en...as your comfort level in the water increases, you will find you need less weight to submerge. For a single tank you should be fine with 30 lbs of lift...you don't need 30 lbs to lift you...you are only slightly negative in the water, you are striving for neutral bouyancy with an empty "wing" and 500 psi at around 15 feet of depth. At this point a couple pounds of lift will make a big difference.

 

[Karl_in_Calif]

BWERB's advice might get you killed, Chavodel8en.

If BWERB were talking about a drysuit, then I could agree with him/her.

Since you are talking about a 7mm wetsuit with 14mms overlap in some sections, be careful who you listen to.

Karl_in_Calif stated...
You would be better off with a drysuit. Then you could drop your weight down to about 28 to 30 lbs.

Did you read that part carefully, BWERB ?

 

[bwerb]

Karl_in_Calif once bubbled...
BWERB's advice might get you killed, Chavodel8en.

If BWERB were talking about a drysuit, then I could agree with him/her.

Since you are talking about a 7mm wetsuit with 14mms overlap in some sections, be careful who you listen to.


Did you read that part carefully, BWERB ?

What's your point? Suit compression? So what if the suit compresses...he still doesn't need a BC with 45 lbs of lift to offset the compression...I also seriously doubt that he needs anywhere close to the amount of weight he's using. Dive a balanced rig...be able to swim it up in case of a total wing failure. If you need the full 45 lbs of lift to overcome suit compression, you are grossly overweighted.

Again...all your wing needs to do is offset your inherent negative bouyancy at depth which even with a fully compressed wetsuit isn't very much in the big picture diving a single aluminum 80 tank with a 7/14mm wetsuit.

The full capacity of the wing is most important on the surface for keeping your rig afloat.

You still didn't answer the west coast/east coast BC question.

 

[Scubaroo]

Karl_in_Calif once bubbled...
BWERB's advice might get you killed, Chavodel8en.

Comments like this are unnecessary, Karl_in_Calif. A much more constructive approach would be to explicitly point out the loss in buoyancy caused by wetsuit compression, which at 120', is significant, and back it up with some math.

 

[Spectre]

Karl_in_Calif once bubbled...
Any back inflation B/C with a stated wing capacity that equals or exceeds the sum of your lead weights plus the negative buoyancy of your full tanks, plus flashlight, plus reg, plus camera etc should work.

This is incorrect. Your wing capacity needs to be able to offset two things. The negative weight of the gas in your tanks, and the negative weight of the compression of your exposure suit.

That's it. Nothing more. The heaviest you will be is on the bottom at the very beginning of a dive, because you have the full weight of the gas in your tanks, combined with the compression of your suit. As you use the gas, you get lighter and remove gas from your wing. As you ascend, you vent the gas that expands from your wing, and the gas that was compensating for the compression of your suit.

 

[LittleFrog]

bwerb once bubbled...


Chavodel8en...as your comfort level in the water increases, you will find you need less weight to submerge.

Yepperz...I was able to drop 8 lbs. within a few dives after completing my OW classes and look forward to dropping a few more.

I'm always looking for more buddies, Chavodel8en....PM me if you'd like to dive.

~LittleFrog