Which XDeep BCD should I get? Help me with my analysis paralysis

[LeggoDiveyDivey]

1. Interesting app - what is it?
2. That's a huge amount of lead, are you sure? Just for reference, with a very similar setup I might use ~2kgs

<EDIT> I made some back of the envelope, hand-waving estimates a little while ago Apeks WTX D18

1. Scuba buoyancy calculator
2. Yes to be conservative I based it on what I used with a 7mm. So its:
7mm+: 8kgs (I sink fast, so likely overweighted)
5mm: 4-6kgs.
Rash-3mm: 2-3kgs.

Its my first time trying it out so its a learning journey too.

 

[boqurant]

Thanks for the link, I'll take a look.
Re the 8kgs, fair enough if that's for 7mm - I thought you still meant the 3mm, given that the (very rough) rule of thumb is 0.9kg bouyancy per mm (and your screenshot has +1.8kg for the wetsuit). Still seems a little on the heavy side so worth experimenting...

Re the wing, you'll be fine with the conventional 11 to 13 kg sizes, really no need for any more unless you're diving doubles. Give it a try, and I'd be surprised if (once rig is balanced) if you ever inflate it more than 1/2 full when subsurface

 

[LeggoDiveyDivey]

Thanks for the link, I'll take a look.
Re the 8kgs, fair enough if that's for 7mm - I thought you still meant the 3mm, given that the (very rough) rule of thumb is 0.9kg bouyancy per mm (and your screenshot has +1.8kg for the wetsuit). Still seems a little on the heavy side so worth experimenting...

Re the wing, you'll be fine with the conventional 11 to 13 kg sizes, really no need for any more unless you're diving doubles. Give it a try, and I'd be surprised if (once rig is balanced) if you ever inflate it more than 1/2 full when subsurface

It's a tough one! Since it would be sinking about 600 usd into trying something out. On hindsight im sure the cost would be minimal in comparison to the other bits but still.

I agree that the math leans into the Zeos 28 being quite right buoyancy wise, and it might be nice not having to flap around with a large wing.

 

[Pearlman]

I assumed the requirement was for warm water diving. A 7mm wetsuit certainly isn’t for tropical waters, maybe more for temperate waters (South Africa? Galapagos?). If diving colder waters with 7mm and lots of lead then the Zen with 19kg lift may be more appropriate.

On the other hand I’ve never worn (since the lockdown) more than a Scubapro 0.5mm full wetsuit or a 1.5mm shorty in the waters of the southern Indian Ocean to the east Andaman sea and extending into the Indo-China-Pacific waters of the Philippines (ok Nusa Penida required a rental 5mm)…

Hence I came to the belated conclusion after the purchase that I never needed a Zen in the first place and I could have settled for a Zeos had I been wiser before the purchase.

 

[boqurant]

Yep, and a few searches around SB will find related discussions / advice to the effect that - the additional lift of your BC (assuming a properly balanced rig, and achieving that balance might require a "baseline" amount of lift) is mainly needed at the start of an OC dive to displace the weight of to-be-consumed gas, and the compression of your wetsuit.

Eg. On a single AL80 this is approx +2kg worth of required lift, and assume a wetsuit compresses down to a little over half, so a 3mm needs perhaps +1kg lift. Swapping to the outside case for a 7mm, this is still just +3kg lift: combined +5kg total.

One might notice the difference of a few kg lift when bobbing around on the surface, and if in rough seas you might want a life raft of a BC, but otherwise its just unused flappy fabric

 

[Pearlman]

It just occurred to me that the Zeos has a standard design backplate. Does this mean that one could buy another larger wing of any brand (or use ones existing old purchase) and fit it on to the Zeos BP for 7mm cold water diving? And the OP could swap it out and travel to tropical destinations with the Zeos …? But then typically one had want a SS BP to reduce the amount of lead for the dives …

 

[boqurant]

In principle, absolutely: the modularity and standardization is a huge appeal of DIR / GUE / Hogarthian rigs

 

[LeggoDiveyDivey]

It just occurred to me that the Zeos has a standard design backplate. Does this mean that one could buy another larger wing of any brand (or use ones existing old purchase) and fit it on to the Zeos BP for 7mm cold water diving? And the OP could swap it out and travel to tropical destinations with the Zeos …? But then typically one had want a SS BP to reduce the amount of lead for the dives …

Yes thats correct, in my mind:
Zeos = XDeep's standard offering. Standard plate, harness, wing etc. Offers 13kg or 17kg of lift.
Zen = XDeep's custom offering.

I mostly dive in tropical/subtropical waters, and the coldest I've done is 18C with a 7mm, don't plan on going colder.
Coldest:
Regs (1st, 2nd, stages, octo, SPG): 1.5kg
Fins: 2kg
Steel tank: 2kg
Weights: 8kg
Total: 13.5kg
Verdict: Zeos 38 or Zen

Tropical waters:
Regs (1st, 2nd, stages, octo, SPG): 1.5kg
Fins: 2kg
Steel tank: 1.5kg
Weights: 2kg
Total: 7kg
Verdict: Zeos 28 or Zen.

 

[lexvil]

Start with less brand, less math and more diving.

 

[boqurant]

Yes thats correct, in my mind:
Zeos = XDeep's standard offering. Standard plate, harness, wing etc. Offers 13kg or 17kg of lift.
Zen = XDeep's custom offering.

I mostly dive in tropical/subtropical waters, and the coldest I've done is 18C with a 7mm, don't plan on going colder.
Coldest:
Regs (1st, 2nd, stages, octo, SPG): 1.5kg
Fins: 2kg
Steel tank: 2kg
Weights: 8kg
Total: 13.5kg
Verdict: Zeos 38 or Zen

Tropical waters:
Regs (1st, 2nd, stages, octo, SPG): 1.5kg
Fins: 2kg
Steel tank: 1.5kg
Weights: 2kg
Total: 7kg
Verdict: Zeos 28 or Zen.

Are your fins really 2kg negative?

Either way, I think you'll just have to give it a try and see what you're comfortable with. I maintain the Zeos 28 will do everything you need and is the better platform all-round and long-term. XDeep is good stuff, though you're paying a not-insignificant markup for branding. Plenty of less-expensive equivalents abound, e.g. DGX DGX Custom - DGX Gears Singles Harness / Backplate / Wing Package