Weighting options for single tank BP/W

[masterof0]

Currently I have quick ditch pockets (from my other BC) that hold 10lb's each but I suspect they wouldn't be DIR compliant? I keep looking at those plastic buckles as a failure points.

Why would the plastic buckles on your weight pockets be any less DIR compliant than the Halcyon pockets (BC System Weighting | Halcyon Dive Systems) which also have plastic buckles? To create a "ditchable" environment, you will have to introduce a buckle, velco, ripcord, etc that would allow for the weight to be removed easily. I think the bigger concern is if it can be "ditched" accidentally which would create an unsafe environment.

 

[mts0628]

1. I could mount weights on the waistband (lead coloured weight).
2. I could securely mount weights on the plate itself (black coloured weights) this would be like the DSS plates.
3. I could do neither/either 1 or 2 and keep using the quick ditch pockets + belt.

Another question: How do I determine (given these variables)how much weight should be ditchable? If I'm close to neutral with an empty tank at my safety stop is the ditchable portion the weight of the gas (about 5-6lb's).

Hi Dale:
I feel ya' about not being able to buy even a tank!

Now to the matter at hand: first let me say that there will be more knowledgeable people to tell you about DIR but I will give you my opinion on weight distribution. I would use a weight belt, keeping the weights off of my harness. Sure in an emergency we can ditch our canister lights (but I hope we never have to- $$) but I wonder how well those weights would slide off of the harness belt? And forget about the left side with the threaded buckle...

I am trying to find the web page that shows a guy melting lead onto the centre channel of his back plate. He dammed the ends with plumbers putty IIRC, and overall, it was pretty neat. The question came about changing out the STA to bands, but I think that would be easily remedied by making a dam around your wing nuts (maybe get some metal tubing cut to size and trimmed for contours and of course flush with the contour of the plate itself). There's a use for your bare weights. Of course the person had ditchable weight as you should as well. I dunno how much weight that would alleviate from your belt/ pouches, but it's a start. I would then put those coated weights on a weight belt.

And finally, as far as your buoyancy: any weight ditched from, as you said a "close to neutral" standpoint would make you just that much more buoyant. Remember though, we should not be so overweighted that we could not achieve positive buoyancy with the ditching of something. If you have to ditch 20 pounds to help yourself in an emergency, something might be wrong.

I will try to locate that page for you so you get a better idea of the project at hand. Melting lead is pretty easy, but most importantly- don't breathe the fumes. Oh- and never cool molten metal with water (or anything liquid for that matter).

With kindest regards,
Thomas

 

[mts0628]

Here it is! Also, look at this. DO everything outside. Canada? Bundle up too!

Thomas

 

[ligersandtions]

To determine if you need ditchable weight, you need to know how much weight you need (when you're properly weighted) versus how much you can swim up when you have a full tank and a catastrophic wing failure. You can simulate this by dropping down to depth (say 80+ feet) with a full tank and removing all the air from you wing (and keeping a tight squeeze on your drysuit). If you can swim your entire rig up from depth with no aid from your wing or drysuit, you should be fine with having no ditchable weight (i.e. you can put your weight belt on under your crotch strap). If, however, you find that you are unable to swim your full rig up with no help from you wing or drysuit, you will need to have ditchable weight (in the amount of the difference between what you need to be properly weighted and what you can swim up yourself).

If this is incorrect, someone please help me out here. I know this is the way I did it when I was diving in a wetsuit (made sure I could swim up my entire rig at the beginning of the dive from my deepest point with no aid from my wing), but I'm not sure if you have to worry as much about ditchable weight when you have both the wing and drysuit to function as a buoyancy compensator. I assume you would not consider a catastrophic wing failure simultaneous with a catastrophic drysuit failure, but that would be the most conservative way to go...

 

[b1gcountry]

Here's another idea: This is a tail weight pouch from DeepSeaSupply. I use it when I'm using twin AL80's w/ a 4# soft weight (and a DS). I'm not sure you whether you can use it on your single tank rig... maybe...

https://www.deepseasupply.com/index.php?product=10

They won't work with single tanks. They don't even work well with double tanks.

Tom

 

[Gombessa]

If this is incorrect, someone please help me out here. I know this is the way I did it when I was diving in a wetsuit

As you said, when you're diving dry and cold, you gotta rely on your redundant buoyancy. My rig, with full tanks, is about 45lb negative. With a dreaded simultaneous wing and drysuit failure at the beginning of the dive, dropping my ~12lb of ditchable weight still isn't going to be enough to get to/stay at the surface. But short of being hit by something bitey, that's not a likely scenario that I'm planning for.

They won't work with single tanks. They don't even work well with double tanks.

Yeah, I use a tail weight pouch right now. It doesn't work as well as a true tail weight (the soft weight you put inside doesn't fall between the tanks very well, and pushes against the bottom of the BP) but it's good enough.

To those who talk about "ditching" a can light, remember that handing off to your buddy, who should be right there with you, is ditching. But can lights nowadays are 0-3lb negative, almost to the point where there's not much use in ditching them...

 

[gxsr_sarge]

They won't work with single tanks. They don't even work well with double tanks.

Tom

Tom,

With doubles, what's there not to work? You just insert a 4 or 5# soft weight and it just hangs down from the bottom bolt b/t the bp and the tank. The bp "molds" the soft weight into the crevice between the tanks and stays put. The only thing one needs to remember is after the first dive or so, to tighten the wingnut a bit more. I used to just jamb a soft weight in that same spot but it once squeezed its way through the tanks and got lost.

 

[b1gcountry]

Tom,

With doubles, what's there not to work? You just insert a 4 or 5# soft weight and it just hangs down from the bottom bolt b/t the bp and the tank. The bp "molds" the soft weight into the crevice between the tanks and stays put. The only thing one needs to remember is after the first dive or so, to tighten the wingnut a bit more. I used to just jamb a soft weight in that same spot but it once squeezed its way through the tanks and got lost.

The tail pocket pushes the BP away from the tanks. Instead of the tanks riding on the BP, it's now riding on the tail weight. I've not been able to get more than 2lbs into a tail weight without it making the BP bulge out (and wobble). I use a Fred T BP which has a fairly significant bend to it. If you're using a shallow bend BP like the OMS, you will probably have more room to play with.

Tom

 

[Reg Braithwaite]

With a dreaded simultaneous wing and drysuit failure at the beginning of the dive, dropping my ~12lb of ditchable weight still isn't going to be enough to get to/stay at the surface. But short of being hit by something bitey, that's not a likely scenario that I'm planning for.

Your call, of course, but speaking as a n00b single tank diver, what worries me is doing a giant stride into the water and hearing a whoosh as my tank valve O-ring fails. It's a single point of failure for wing and dry suit on a single-tank, single valve rig. Maybe the valve O-ring is an unlikely failure, but my general point of paranoia is that with a single valve, any gas failure hits your breathing and both sources of buoyancy at once. Being able to swim the rig directly or ditch enough weight to swim the rig seems prudent.

 

[Gombessa]

Your call, of course, but speaking as a n00b single tank diver, what worries me is doing a giant stride into the water and hearing a whoosh as my tank valve O-ring fails. It's a single point of failure for wing and dry suit on a single-tank, single valve rig. Maybe the valve O-ring is an unlikely failure, but my general point of paranoia is that with a single valve, any gas failure hits your breathing and both sources of buoyancy at once. Being able to swim the rig directly or ditch enough weight to swim the rig seems prudent.

Hey Reg,

A couple of observations:

1. I can't say I know firsthand what happens when a tank o-ring fails. Does the regulator cease to function completely? If not, you've got two minutes or so to breathe the reg, get situated and fill your wing/suit. Establishing positive buoyancy shouldn't be a problem in this case.

2. Isn't your wing already inflated when you jump in? I don't hear much about negative entries except in cases of getting down in ridiculous current (in which I simply wouldn't dive).

3. If you're truly worried about this, you could go with an argon (or airgon) bottle, or use an H-valve.

4. Realistically, if you're on a boat and just jump off, something as drastic and loud as a catastrophic tank o-ring failure would get everyone's attention, especially the tender's.

5. As long as you can stay on the surface, your tank will be getting lighter as you lose your 6-10lb of gas. I imagine you'd be able to get back on the boat in your hypothetical before it empties and starts taking on water. And if you're really worried about losing *all*your gas that quickly without even being able to fill your wing, what are you going to do when the tank instantly empties and instantly takes on 5-8 gallons of water and suddenly becomes 35-40lb negative? I don't think your ditchable weight will help then.

6. If you get into doubles, you may find yourself running into situations where you simply cannot be balanced if you're intent on stacking multiple failures including your redundancy. With a single tank, you can usually avoid it. But later on, you need to decide whether you really want to be keeping over 35lb on your belt in order to account for an unlikely double-failure.

7. And finally, in case it helps and to keep this on-topic, the rig in question is considered balanced by GUE standards. It's neutral at 10ft with 300psi, and in the worst case is swimmable to the surface with a full tank and either drysuit or wing total failure.