Help with choosing BPW lift

[Filipe Marques da Costa]

Hello everyone,

I'm a beginner diver with around 40 dives over the last year. I've dived enough to understand the importance of owning your own equipment and I am at the moment trying to choose my first BPW. I've read a lot about the subject and the many topics on this forum gave me a world of information that has helped me come to some conclusions. I'm very close to making a decision but would appreciate some insight from more experienced divers.

At the moment I'm very inclined to go with the XDeep Zeos standard. However I am on the fence regarding the lift (28 vs 38). I've read a bit and even played with a fantastic excel spreadsheet I found on these forums that helps calculate necessary wing lift. But I'd like to hear your experience on this. I am 170cm tall and weight about 68kg. I plan to dive 95% of the time single 12L steel tanks, on a 7mm wetsuit, eventually progressing to a dry suit next winter perhaps; I'm choosing the steel backplate. I'm concerned the 28 lbs is cutting it a bit too close. Can anyone provide some experience on this?

 

[Wibble]

A smaller wing is more streamlined. If you’re correctly weighted you don’t need much more than the weight of the variables— gas and SMB+reel — so small is fine. A Halcyon Eclipse 28 pound / 13kg with single tank adapter is great.

 

[BlueTrin]

In addition to what Wibble said, because you are not diving a drysuit, you need to add the change of buoyancy of your 7mm at depth.

 

[Shabaday]

Hello everyone,

I'm a beginner diver with around 40 dives over the last year. I've dived enough to understand the importance of owning your own equipment and I am at the moment trying to choose my first BPW. I've read a lot about the subject and the many topics on this forum gave me a world of information that has helped me come to some conclusions. I'm very close to making a decision but would appreciate some insight from more experienced divers.

At the moment I'm very inclined to go with the XDeep Zeos standard. However I am on the fence regarding the lift (28 vs 38). I've read a bit and even played with a fantastic excel spreadsheet I found on these forums that helps calculate necessary wing lift. But I'd like to hear your experience on this. I am 170cm tall and weight about 68kg. I plan to dive 95% of the time single 12L steel tanks, on a 7mm wetsuit, eventually progressing to a dry suit next winter perhaps; I'm choosing the steel backplate. I'm concerned the 28 lbs is cutting it a bit too close. Can anyone provide some experience on this?

I have the Xdeep Zen in SS and the Xdeep Ghost for travel. I find the lift in those to be quite adequate and quite streamlined. I believe it is closer to 19kg for the Zen and 17kg for the Ghost.

 

[inquis]

The wing compensates for the weight of the gas you haven't breathed and wetsuit compression. A 12 L has about 5.5 lb non-reserve gas. An XL Bare Reactive 7mm (single layer) wetsuit has 16 lb of buoyancy. When properly weighted, the most the wing would need to lift is 22ish lb, usually will be less, so the 28 lb would be plenty in that case. If you have a double-layer 7mm, the 38 lb would be a better choice.

 

[Wibble]

The wing compensates for the weight of the gas you haven't breathed and wetsuit compression. A 12 L has about 5.5 lb non-reserve gas. An XL Bare Reactive 7mm (single layer) wetsuit has 16 lb of buoyancy. When properly weighted, the most the wing would need to lift is 22ish lb, usually will be less, so the 28 lb would be plenty in that case. If you have a double-layer 7mm, the 38 lb would be a better choice.

Is it really as much as 16lb/6kg of buoyancy change with a wetsuit from surface to "deep"?

(I never dive in a wetsuit so please excuse my ignorance!)

 

[inquis]

Is it really as much as 16lb/6kg of buoyancy change with a wetsuit from surface to "deep"?

No, but it will never be more than that.

 

[Wibble]

No, but it will never be more than that.

OK.

What's the sort of depth that this change takes place? First 10 metres (33ft)? Or deeper?

 

[inquis]

What's the sort of depth that this change takes place?

Assuming the suit is made of air (as the most compression loss it could ever have), it's 1/2x at 10 m, 1/3x at 20 m (66% loss), etc. A conservative estimate to be sure! For simplicity, I just use 100% loss as an upper bound. The 1/atm is a tighter (more realistic) bound. Reality is even less.

 

[Wibble]

Thanks, good to know. Kind of think one day I might dive in a place that's warm enough to use a wetsuit!

Although the other benefit of a drysuit's the redundant buoyancy.