Wing bladder size and suggestion for backplate/harness system

[saxman242]

Thanks, I’m now looking into the Hollis ST35 which seems nice, do you have any experience with any of these?

I have a Hollis S38 and an ST22. I have nothing but good things to say about them.

 

[saxman242]

Also on a separate note the Hollis St system has a couple of D rings on each shoulder

I haven't used the st harness, but I do have the older hollis comfort harness that also came with 2 d rings on each shoulder strap. I've never found a use for the 2nd pair and just remove them.

 

[inquis]

Remember if your rig can't float you in your rig, weighted, in a flooded dry suit, you need to be able to ditch significant weight extremely reliably and pretty quickly.

With regard to the "significant/quickly" aspects, don't you think it depends on the discrepancy between wing capacity and total ballast?

I use a 22 lb/10 kg wing and 11 kg lead in colder water split between 5 kg on a weightbelt and 6 kg on the rig. I would be about 8 lbs (3.5 kg) negative if the suit totally flooded, which I can easily swim up without dropping any weight. I'd also have a fair bit of time on the way up to work out the release (which I would do if the boat/shore were not immediately accessible). Obviously, if wing capacity is woefully short, the urgency increases.

What I do think is critical is that I've worked out in advance what to do, and there is no need to panic.

 

[inquis]

I’m guessing the salt water adjustment though only counts when I’m wearing the rig no?

Yes, I see what you're saying, and you're correct. This earlier statement is in error:

With that included, your drysuit buoyancy -- and thus total ballast required -- is about 21.5 lb to be neutral

The total ballast required is the suit buoyancy plus the 6.5 lb salt water adjustment = 28 lb. With the additional 6 lbs of air, the integrated rig buoyancy winds up at -34 lbs at the start of the dive. I'm sorry for the false conclusion -- the 30 lb wing does not work with all weight integrated on the rig. As for your earlier question about 4 kg on a belt, yes the 30 lb wing would easily work in that case.

 

[-JD-]

With regard to the "significant/quickly" aspects, don't you think it depends on the discrepancy between wing capacity and total ballast?

I use a 22 lb/10 kg wing and 11 kg lead in colder water split between 5 kg on a weightbelt and 6 kg on the rig. I would be about 8 lbs (3.5 kg) negative if the suit totally flooded, which I can easily swim up without dropping any weight. I'd also have a fair bit of time on the way up to work out the release (which I would do if the boat/shore were not immediately accessible). Obviously, if wing capacity is woefully short, the urgency increases.

What I do think is critical is that I've worked out in advance what to do, and there is no need to panic.

Magnitude of the buoyancy deficit obviously makes a big difference, no doubt.
If that flood happens near the beginning of the dive when you still have significant air weight too ...

I was trying to be measured, not alarmist - I guess I missed. But, for me, it really comes down to:, in a flooded suit, in cold water, just how long do you want to be treading water as you futz around trying to get positive with limited dexterity (thick gloves and/or numbed fingers)??? To me that means the ability to ditch enough weight to be comfortably positive, easily and reliably.

I can't make the math work where I would be comfortable using a 22lb wing with a drysuit and a typical backplate rig. Even with no lead, but factoring an HP120, pony, regs, etc there just isn't much of any margin in a flood. Of course sans-suit, I float with only my mouth and nose out of the water, so I really prefer positive net bouyancy with everything else.

 

[inquis]

I can't make the math work where I would be comfortable using a 22lb wing with a drysuit and a typical backplate rig.

Aluminum plate and AL80 tank might explain it, though I rarely use that configuration. With the undergarments I use 99% of the time, I'm positive with a flooded DS (and full wing, of course) without ditching weight.

I think the takeaway on which we would agree is this stuff should be understood before getting wet. How much, if any, to ditch if the wing fails or suit floods in order to achieve a safe/controlled ascent. And honestly, understood before purchase, as the OP is fortunately doing.

ETA: OP, I briefly mentioned it before, but that's one of the other trades to consider in your selection:

• A 40 lb wing is bigger than necessary for hopefully 99.9% of your diving, but in the event of a flooded drysuit, just hit the inflator button.
• A 30 lb wing with some lead on a weightbelt is optimized for hopefully 99.9% of your diving but in the event of a flooded drysuit, you'd need to hit the inflator button AND ditch the weightbelt.

 

[Wibble]

What if I moved 4kg to a belt and kept about 8kg on the rig? 35lb wing could be good then? I know maybe at that point a 30lb wing would also be enough but I’d rather also maybe not be at the edge of what the wing can take and have a little extra.

You’ll be using steel 12 litre 232 bar tanks in Scotland. This will need less lead.

Regarding the harness, a one-piece will be fully configurable to your requirements: if you want two chest D-rings each side, that’s fine. Same with waist D-rings.

 

[Giovanni Giuriani]

Thanks everyone for all the info. I think I’ll definitely need to wait until I know how much weight I need when diving in my drysuit before making my decision. Although I might have to adjust that a bit considering I m diving currently in an Apeks black ice which is quite bulky and I’d expect maybe more positive than smaller BCs.

I’m now also looking at the OMS smartstream system with 32lb wing. Any experience with this system or brand?
I like this because it has integrated trim weight pockets on the backplate, an adjustable harness (any thoughts on these?).
It doesn’t have a steel STA which would add a little extra lead needed but I’m also not sure whether the steel STA are better/needed than just having the wing attached to the plate via the bands and then having little bars on the wing to keep the tank in place?

Sorry if I keep changing the topic of the thread but you guys have been so helpful I’m trying to get as much info as possible.

 

[brsnow]

Thanks everyone for all the info. I think I’ll definitely need to wait until I know how much weight I need when diving in my drysuit before making my decision. Although I might have to adjust that a bit considering I m diving currently in an Apeks black ice which is quite bulky and I’d expect maybe more positive than smaller BCs.

I’m now also looking at the OMS smartstream system with 32lb wing. Any experience with this system or brand?
I like this because it has integrated trim weight pockets on the backplate, an adjustable harness (any thoughts on these?).
It doesn’t have a steel STA which would add a little extra lead needed but I’m also not sure whether the steel STA are better/needed than just having the wing attached to the plate via the bands and then having little bars on the wing to keep the tank in place?

Sorry if I keep changing the topic of the thread but you guys have been so helpful I’m trying to get as much info as possible.

I added integrated weight pockets to my sub gravity aluminum paragon set up. They have different size choices, I went small. Nice thing is they come right off with one screw for my warm trips when I only need the trim pockets. Still keeps it clean and clutter free.

 

[Wibble]

I m diving currently in an Apeks black ice which is quite bulky and I’d expect maybe more positive than smaller BCs.

I’m now also looking at the OMS smartstream system with 32lb wing. Any experience with this system or brand?
I like this because it has integrated trim weight pockets on the backplate, an adjustable harness (any thoughts on these?).

I started off with a Black Ice. Sold it as soon as I moved to a backplate+wing and never looked back. Hated the silly weight pouches which fall out and break. Hated the horseshoe wing design (needed to flip sideways to balance it). Hated the cliptastic harness which wasn't properly adjustable. Hated the stupid logos and graphics.

Anyway, a simple one-piece harness costing next to nothing new is way more effective than the clip-tastic pseudo harnesses that come with the "Tech!" gear.

The backplate, for Scotland, will be a normal 3mm stainless one. Second hand -- you can't break a backplate!

You will need the single tank adapter with 4 pouches so you can use smaller weights for fine adjustment. When diving in warm locations you'll probably find you don't need any additional weight.

A "doughnut" wing is far more comfortable to dive in and doesn't suffer from the lopsided buoyancy of a horseshoe. It needs a standard dump by the left hip. Remove the toggle and tie on a Cobra Knot.


That's it.