DIR- Generic Bulk without warmth?

[Barefoot_Lawyer]

In my Fundies class I dove an AL backplate with zero weight and still had a decent amount of air in my wing at 500psi with HP100 doubles. I am wondering if anyone has a good recommendation for something to add some bulk / buoyancy without being too hot. The 4E Arctic is too good at being low bulk for me I guess. Otherwise a set of AL80 doubles may be in my future.

 

[Big-swede]

Add some extra air in your drysuit or wing. That does the trick for me when i want to be more floaty.

 

[DiveLikeAMuppet]

Eat more to get gain a bit of floaty bioprene? Or buy a carbon fibre backplate for warm water diving?

You don’t want bulky undersuit unless you need it for warmth.

 

[ginti]

Why do you want to have more gas in the drysuit? Your situation is actually optimal

PS Water temperature?

 

[elmo]

My suggestions would be to try one or all of
a) dive with aluminium cylinders so you need less buoyancy
b) dive in colder water
c) slow down and relax. You’ll probably find you want more warmth

If that doesn’t do it for you and really need high-volume low-warmth undergarments then go for cotton. Thermal properties are poor and it can be bulky. Find that really comfortable pair of old cotton tracksuit pants, a cotton t-shirt and a cotton jumper.

 

[Badger7]

In my Fundies class I dove an AL backplate with zero weight and still had a decent amount of air in my wing at 500psi with HP100 doubles. I am wondering if anyone has a good recommendation for something to add some bulk / buoyancy without being too hot. The 4E Arctic is too good at being low bulk for me I guess. Otherwise a set of AL80 doubles may be in my future.

Yeah, I understand your line of thinking, but if you need that extra gas to be neutral, the only benefit of moving it from your wing to the suit is that its easier to dump the expanding gas from the suit on ascent. Other than that, it would be really nice to be able to shed the extra gas entirely, and less weight same volume is the only thing that's going to get the job done. The other thing about just forcing the extra air into your suit with bulkier undergarments is you have no control where the extra air is going to sit and entirely possible it might push your trim out of wack in the process. Plus, there's no such thing as bulk without warmth underwater. On the surface you could be looking for undergarments that are bulky but permeable to let some steam out and air through, but once you zip up your trilam, bulk is going to equal insulation.

Do you have any feel for the amount you're overweight? Switching to a pair of AL80s from a pair of HP100s will be the buoyancy equivalent of dropping 7.6 pounds of lead. You'd also be losing 47cuft of gas, which sounds like a pretty ****** tradeoff. Something tells me you're not 8 pounds heavier than neutral. I wonder if we can shed some weight elsewhere?

I quantified how much doubles are going to put me overweight by dialing in neutral with a single tank. I'm currently at 2 pounds of lead with current drysuit undergarments, single HP100, steel backplate, fully kitted out. Adding another 500psi HP100, a manifold and hardware, another 1st stage, and stainless tank bands will add about 7.2 pounds. Dropping the lead brings that to 5.2 over, switching from a steel backplate to an AL backplate should bring that down to 2 pounds overweight. Lets for a moment assume that's your target, that at 500psi you're sitting with sufficient air in the wing to lift those 2 excess pounds of weight.

What other options do we have to drop a couple pounds of negative buoyancy other than the tanks? Carbon fiber BP was mentioned, but that comes at a pretty hefty cost for only a .5 pound weight savings, but certainly on the table for discussion. Aluminum triglides and d-rings? Lighter backup lights or backup lights with the same weight and larger volume? Lighter primary light? Fins that are the same stiffness but less dense? Plastic waist buckle instead of stainless? Delrin spool vs aluminum? Point being, I'm wondering if you can shed that extra weight elsewhere instead of just moving the gas? What else do you have on you that is heavy metal that you can switch to aluminum or delrin?

I've got a set of spring scales for determining the negative buoyancy of objects underwater. Next time we're diving the same mudhole I could bring them with to see if any of your gear is more negative than you're expecting, and quantify it.

 

[ginti]

Yeah, I understand your line of thinking, but if you need that extra gas to be neutral, the only benefit of moving it from your wing to the suit is that its easier to dump the expanding gas from the suit on ascent.

I am not sure if I can follow you.

Gas in the suit is harder to dump than gas in the wing because it can move much more. More gas in the drysuit usually means gas going to the legs or moving around, making it more difficult to dump, not easier (or, at least, making it more difficult to dump the gas one needs to dump).

 

[Badger7]

I am not sure if I can follow you.

Gas in the suit is harder to dump than gas in the wing because it can move much more. More gas in the drysuit usually means gas going to the legs or moving around, making it more difficult to dump, not easier (or, at least, making it more difficult to dump the gas one needs to dump).

I dunno, If I've got a spool in my left hand and reeling line with my right hand during an ascent, I need to temporarily free up a hand to dump wing gas from my dump valve or deflator button. Dumping gas from the suit is just a matter of running the valve wide open and lifting an elbow, hands free. One feels slightly easier than the other to me. "Extra gas" during ascent expansion rises to the highest point in the suit. Making the shoulder dump the highest spot during ascent means the expanded gas bubbles right out. You can feel free to extend your legs if you feel they're trapping some extra gas. Obviously we need to dump off expanding gas in both during ascent, it isn't either/or, but I do find it slightly easier to manage the expanding gas bubble on ascent in the suit than the gas in the wing for reasons stated above.

Maybe an entirely bad example, I was just trying to illustrate that moving gas from the wing to the suit might have a small benefit, but still might not be the best move. If you don't have a bunch of extra gas in your wing or suit at the end of the dive, less needs to be dumped on the way up.

In an ideal world I'd like to end a dive with zero gas in the wing so I don't need to manage it at all on the way up, just take really deep breaths and slowly exhale, let the shoulder dump do its job. However, I'd bet OP is more often than not doing two MDL dives on the same set of doubles, so he's going to be managing quite a bit of gas in his wing during the first ascent anyway, its not avoidable, but he's saying current situation is less than ideal because even in the perfect scenario of finishing a dive with 500psi minimum gas, he still has a "decent amount" of air in his wing to remain neutral, and hasn't quite reached the holy grail of the perfectly balanced rig.

 

[Barefoot_Lawyer]

Yeah, I understand your line of thinking, but if you need that extra gas to be neutral, the only benefit of moving it from your wing to the suit is that its easier to dump the expanding gas from the suit on ascent. Other than that, it would be really nice to be able to shed the extra gas entirely, and less weight same volume is the only thing that's going to get the job done. The other thing about just forcing the extra air into your suit with bulkier undergarments is you have no control where the extra air is going to sit and entirely possible it might push your trim out of wack in the process. Plus, there's no such thing as bulk without warmth underwater. On the surface you could be looking for undergarments that are bulky but permeable to let some steam out and air through, but once you zip up your trilam, bulk is going to equal insulation.

Do you have any feel for the amount you're overweight? Switching to a pair of AL80s from a pair of HP100s will be the buoyancy equivalent of dropping 7.6 pounds of lead. You'd also be losing 47cuft of gas, which sounds like a pretty ****** tradeoff. Something tells me you're not 8 pounds heavier than neutral. I wonder if we can shed some weight elsewhere?

I quantified how much doubles are going to put me overweight by dialing in neutral with a single tank. I'm currently at 2 pounds of lead with current drysuit undergarments, single HP100, steel backplate, fully kitted out. Adding another 500psi HP100, a manifold and hardware, another 1st stage, and stainless tank bands will add about 7.2 pounds. Dropping the lead brings that to 5.2 over, switching from a steel backplate to an AL backplate should bring that down to 2 pounds overweight. Lets for a moment assume that's your target, that at 500psi you're sitting with sufficient air in the wing to lift those 2 excess pounds of weight.

What other options do we have to drop a couple pounds of negative buoyancy other than the tanks? Carbon fiber BP was mentioned, but that comes at a pretty hefty cost for only a .5 pound weight savings, but certainly on the table for discussion. Aluminum triglides and d-rings? Lighter backup lights or backup lights with the same weight and larger volume? Lighter primary light? Fins that are the same stiffness but less dense? Plastic waist buckle instead of stainless? Delrin spool vs aluminum? Point being, I'm wondering if you can shed that extra weight elsewhere instead of just moving the gas? What else do you have on you that is heavy metal that you can switch to aluminum or delrin?

I've got a set of spring scales for determining the negative buoyancy of objects underwater. Next time we're diving the same mudhole I could bring them with to see if any of your gear is more negative than you're expecting, and quantify it.

I am looking for something bulky but not compressible that would hopefully hold the air (mostly) in one spot for what I would call a summer fundies-depth-only setup to mimick wearing more thermals without being as warm. If I go to 30’ or especially 60’ at Wazee, the Arctic by itself is not enough. I would wear enough extra buoyancy (gloves, thicker hood, long underwear) for warmth that I get a lot closer to zero air in my wing. 15 to 20 feet is above the thermocline and is pretty warm. I also don’t want to roast on the surface. I am nearly positive I will be diving AL80’s with Emoke for my tech upgrade, but I should ask. PS - Don’t threaten me with a good time!

PS Water temperature?

Fundies @Gilboa in Ohio was 78 degrees. Fundies tech upgrade practice @Wazee is 70+ right now at 20’, but that’s a 3 hour drive. The mud hole 1 hour from my house (Square Lake) is 75.

 

[Badger7]

I am nearly positive I will be diving AL80’s with Emoke for my tech upgrade, but I should ask. PS - Don’t threaten me with a good time!

If this is going to be the case, you're going to want to manifold up a pair of AL80s now to make sure you're comfortable with the trim and bouyancy before heading down to MX. Still freshwater right? You can use your existing valves and bands on a pair of AL80s and hit the local dive spot, make sure there's no surprises and figure out exactly how much lead you need to add and where to put it.

For local diving with steel tanks, if you need more bulk AND more warmth - maybe consider layering, even something non-scuba, like a plain fleece sweatshirt and pants over your current undergarments. I'm surprised though, we're not that different in shape or size, and I dumped my arctics entirely at Wazee, even at 80' and 39 degrees, just using a thin merino base later with Meshtec top and bottoms, which are just slightly less warm than arctics, but are very breezy topside for cooling off during a SI.