Apeks bp/w + Reg set package enough lift? (30lbs)

[Berry Ke]

Hi there,

I have been searching for a general rule to decide how much lift capacity I need but I just can really wrap my head around it.

I'm interested in buying this set Apeks Single Cylinder Tek Set

It's a pretty good price considering what all the pieces (regulator set + bp/w) cost separately. My only concern is that the lift capacity is a little small (30lbs) for my needs.
I dive cold fresh and warm sea water with a 7mm wetsuit with cap, I dive 12L or 15L single tank. I weight 72kg and use 6kg lead in fresh water.

Unfortunately I'm not able to test this setup on the water so only way for to decide if this is enough is to calculate it. Which I don't know how/don't feel confident doing in my own before buying such a piece. I'm going to give the shop a call tomorrow anyway to check if it's possible to get this deal with a 40lbs blatter, but if they can't do that I'd still like to get this package if the lift is enough.

Any suggestions/opinion on the lift or this package in general?

 

[Froggle]

I find my 30lb wing to be more than adequate for cold water diving with a 15litre cylinder, a heavy torch and 10kg of lead. I generally use a dry suit but I've also used it with a 7mm semi-dry with hood and gloves.
By comparison my wing for manifolded twin 12's and stages is only 45lbs.

 

[runsongas]

I use a 30lb apeks wing for a hp100 and a drysuit running 24lbs total ballast without issues in norcal. the 40 is rarely necessary except if you were using high amounts of weight to compensate a very large amount of neoprene and a large tank.

 

[Berry Ke]

Okay, maybe it's the newbies reflex like more is better?

I hope I don't need to go thrue the hassle of getting the shop to adapt the package /change the battery with a bigger one, but if it is needed I think either the WTX4 or the WTX-D40 would the best options. They seem fairly equal, anyone knows if one is better than the other for single tank?

 

[Froggle]

The WTX-D40 is a single cylinder wing with 40lbs of lift. The WTX4 is a horseshoe shaped 45lb twinset wing so is unsuitable for singles as it's too wide and will wrap around the cylinder.
I was a little concerned when I first got my 30lb wing but, after seeing a video a buddy took at 36 metres showing the wing to be nowhere near fully inflated, I stopped worrying about it. I've even recovered a 10kg weight belt from 22 metres that a buddy accidentally dropped from the surface whilst I was using it.
Ultimately you're better off with as small a wing as you can get away with as it's more streamlined in the water.
The only thing that I would say about the package is that it has no STA included and I find 15 litre cylinders to be a little unstable without.

 

[stuartv]

If you only need 6kg of lead with your 7mm suit, a 30# wing should be plenty of lift.

 

[John C. Ratliff]

Hi there,

I have been searching for a general rule to decide how much lift capacity I need but I just can really wrap my head around it.

I'm interested in buying this set Apeks Single Cylinder Tek Set

It's a pretty good price considering what all the pieces (regulator set + bp/w) cost separately. My only concern is that the lift capacity is a little small (30lbs) for my needs.
I dive cold fresh and warm sea water with a 7mm wetsuit with cap, I dive 12L or 15L single tank. I weight 72kg (159 lbs) and use 6kg (13.2 lbs) lead in fresh water.

Unfortunately I'm not able to test this setup on the water so only way for to decide if this is enough is to calculate it. Which I don't know how/don't feel confident doing in my own before buying such a piece. I'm going to give the shop a call tomorrow anyway to check if it's possible to get this deal with a 40lbs blatter, but if they can't do that I'd still like to get this package if the lift is enough.

Any suggestions/opinion on the lift or this package in general?

Just looking at your weight and the amount of lead you use above (which I converted to pounds), I doubt you need more than 30 pounds of lift. Remember that BCD stands for "buoyancy compensation device." You are simply compensating for the loss of buoyancy of your wet suit. You apparently already have your tanks, so find the specs on the tanks to see how negative they are at the beginning of the dive when full. Add to that the weight of the stainless steel backplate, and the amount of weight you are using. Assume that you'll loose all the buoyancy in your suit at about sixty feet of fresh water, and your BCD will need to compensate for that loss with its lift capability for you to remain neutrally buoyant in the water.

You can test your buoyancy needs by taking your full wetsuit into a pool and a weight belt, and finding the amount of weight needed at the surface so that on a full breath, only your eyes are above water. That is the total weight you need to be neutral in the water. At depth, your wetsuit will loose almost all of that weight and your BCD will need to compensate for that amount of loss.

Because salt water is more dense, you'll need proportionately more weight, and, "...Fresh water has a density of 1.0 while salt water has a density of 1.025. From this, you can see that salt water is slightly heavier than fresh water. The ratio between the two is 41:40...".
http://geography.about.com/od/physi...ference-Between-Salt-Water-vs-Fresh-Water.htm
Therefore you will need proportionately more weight in salt water, but since both the wetsuit and the tank, backplate/weights are slightly more buoyed up in salt water, you probably don't need an increase in the BCD capacity.

SeaRat

 

[elmo]

I rarely dive single tank and wetsuit now, but when I did it was a 12l steel tank with a 7mm wetsuit, hood, and a 25lb wing. That was plenty of lift. I weigh a little more than you and used a little less weight with an aluminium backplate. 25-30lb is ideal for a single tank if you're reasonably weighted. More and you're just creating extra drag, and on the surface extra lift will push you face foreward (easy to overcome but why give yourself a hassle). You'll get used to floating on the surface with your head out of the water but shoulders under.

 

[HantsDiver]

The wing will be fine.

However are you sure you could swim up from depth in the event of a wing failure? It doesn't matter if it's 30/40lb if it fails.

If you arn't your options are: drysuit or a lift bag.Both will work fine in the event of a problem.

 

[stuartv]

Remember that BCD stands for "buoyancy compensation device." You are simply compensating for the loss of buoyancy of your wet suit.

... and the weight of the gas in your tank(s).

If your suit loses 20# of buoyancy at depth, a 20# wing is not enough. Even if you are only carrying a single AL80, it holds 6# of gas, so, at the start of you dive, after your suit loses 20#, you will be 26# negative on the bottom.