double tank weighting issue?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

May I ask why you need a wight belt with doubles? They are usually heavy enough not to need a belt?!!! So what is going on with your set up? You shouldn't have to wear one! Did I miss something?

I'm fine in the thin undergarments, but when I don my Pinnacle Merino wool ones, I find that I need about 8lbs extra to be neutral at empty. I dive twin X8's with a steel BP.
 
Yes, indeed, you have missed plenty.

Your non-ditchable weight would ideally make you neutral (not buoyant) in the water at the beginning of your dive. And your weight belt would provide the added ballast to make you neutral at the end of your dive, when your tanks are lighter.

Thus at any point in your dive you could ensure neutral or slightly positive buoyancy by dropping your belt if absolutely necessary, if an NDL dive, or else allow you to establish positive buoyancy at the surface at the end of your dive.

That is what you are missing.

no not really. My point was in a dive with a deco obligation, I don't want inadvertently ditchable weight - and all "ditchable" systems can be inadvertently ditched. so, I want to be weighted so I am neutral with 0 psi in my tanks - to avoid any problems maintaining my position in the water column while airsharing at a deco stop.
 
Gill nets fish for everything

Science, baby, science.

If I were to get caught in a gill net, the last thing I would want to do is come out of my rig.

I weighed in on the previous thread and realize that I'm probably beating my head against the wall here, but let's see some pictures of this balanced rig with the 26 lbs of flotation attached to it. I suspect a picture will be worth a thousand posts in this case. :D
 
And just for comparison, in my double Worthington LP85s, steel H plate, can light, crushed neo suit, and Pinnacle merino undergarments (for MA waters), I have a 6# belt. Not too bad at all. It's about what I wear in a single (HP100) and weighted DSS plate.
 
If I were to get caught in a gill net, the last thing I would want to do is come out of my rig.
How would you disentangle?

I weighed in on the previous thread and realize that I'm probably beating my head against the wall here, but let's see some pictures of this balanced rig with the 26 lbs of flotation attached to it. I suspect a picture will be worth a thousand posts in this case. :D
I may have some pictures of our Farber experiment. I'd been out to Hawaii to work with Rich Pyle. That was some time ago, prior to the availibility of the Cis-Lunar equipment he now uses. I was looking into the use of his open circuit rig by some of our geologists who needed to do some very deep diving in the South Pacific. We had a couple of donated Farber 100s kicking around the dive locker. Nobody had any real use for them and we were using them as part of our fly-away surface supplied system. We decided to experiment with some concepts and used the 100s for that. If memory serves, they whole thing weighed in at about 100 lbs. (giving new meaning to the moniker "100"). In the water, with the foam, they were fine, with the usual inertia effects of that sort of load, but out of the water they were a complete pain.
 
And just for comparison, in my double Worthington LP85s, steel H plate, can light, crushed neo suit, and Pinnacle merino undergarments (for MA waters), I have a 6# belt. Not too bad at all. It's about what I wear in a single (HP100) and weighted DSS plate.

For single tank diving, my belt is normally around 6 lbs. This roughly approximates the weight of the gas in the tank, and therefore it is the perfect amount of ditchable weight for either a drysuit or for a thin wetsuit.

For twin tank diving, my belt is normally around 14 lbs, for the same reasons.

This is what I would also recommend for others, since that is what I am doing as well.

Additionally, I recommend against thick wetsuits under any circumstances, except freediving in cold waters. Thick wetsuits are a cheap solution for cold water scuba, but a very bad and dangerous solution. Therefore in all the above posts, I am presuming the use of either a drysuit or else of a thin wetsuit.

Going with no ditchable weight, it seems to me, is fraught with dangers. And although ignorance of the dangers is bliss, it is not smart.
 
no not really. My point was in a dive with a deco obligation, I don't want inadvertently ditchable weight - and all "ditchable" systems can be inadvertently ditched. so, I want to be weighted so I am neutral with 0 psi in my tanks - to avoid any problems maintaining my position in the water column while airsharing at a deco stop.

Now you are ignoring the early stage of the dive that is pre-deco, as well as the late stage of the dive, when you are in deco but your back-tanks are almost empty.

Thal has also pointed out the need to be neutral as well outside of your rig, if you should need to take it off underwater to disentangle.

As I said before, you are missing a lot.
 
Going with no ditchable weight, it seems to me, is fraught with dangers. And although ignorance of the dangers is bliss, it is not smart.

For most in this conversation the difference is between a balanced rig (DIR) or balanced rig+balanced diver (Thal). Not sure why you think ditchable weight is crucial. I know I'm much more worried about my belt detaching (which I had happen at 90' on the Yukon, and yes, I run it under my crotch strap) than about the need to ditch weight. I can stay at the surface with an empty wing and little gas in my suit just fine for short stays (I know, it's how I jump into the water), and can always ditch gear if needed.
 

Back
Top Bottom