DIR- GUE Balanced rig with a thick wetsuit - mathematically impossible?

[L13]

Are you suggesting that having a flooded suit or either kind makes it negatively buoyant? Any water that gets into a suit doesn't make it heavier(until you exit the water)

No, but the weight you used to sink it when it was full of air does make you negative.

Have a plan.

 

[jadairiii]

.... common DPV motors always spun clockwise which implies you have to drive the scooter with your right hand and stages naturally go on the left to stay out of the prop wash. But divers who lack experience with tow-behind scooters sometimes struggle to follow that logic.

Dont forget, more than the issue of the prop wash, we had some pretty big can lights on our right side. Bottles on your right would limit your ability to access that light to turn it on/off, and the can light was actually "ditch weight" in an emergency (they were a tad heavy "back in the day"). Even today, per DIR, dont cover your can light with a stage/deco bottle.

Second, hose routing doesn't work either, all hoses come from the left, over the right shoulder.

Obviously, before someone chimes in, this is back-mount only, side-mount is a different tool, different protocols.

 

[Celt]

Are you suggesting that having a flooded suit or either kind makes it negatively buoyant? Any water that gets into a suit doesn't make it heavier(until you exit the water)
I had a dive shop owner warn me that if my drysuit flooded, I would drown.

If you replace air with water yes you lose buoyancy. I’ve been in both flooded, the neoprene will maintain the buoyancy of the material, the bag suit will be neutral but the drag of both will be such that’s it’s impossible to swim up. I tore open the zipper of a Nothern Diver 8mm neoprene dry suit working under a bridge and in order not to dump my weight belt i had to crawl up an embankment. I cut the boot of an Otter Britannic bag suit climbing out of a heat exchanger on a wreck we were salvaging copper off.

 

[admikar]

So, long story short: yes, you can't dive balanced rig in a thick wetsuit?

 

[Nick_Radov]

For you DIR folks. Based on my SAC (pretty much right in the middle) I used double 100's prior to going closed circuit. I know other OC tech divers who use bigger tanks for the dives they do.

In my drysuit with my thickest undergarments in salt water the steel tanks with a AL 40 deco bottle has me overweighted with zero lead, what is the balanced rig answer to this?

The answer is to use a carbon fiber backplate. If that still leaves you overweighted then trade your back tanks for different ones that are less negatively buoyant. It's not the size of the tanks that matters as much as the buoyancy.

The deco bottle isn't really a factor here. A full deco bottle is going to be a few pounds negative, but if you have a wing failure at the beginning of the dive when your back tanks are still full then you can ditch the deco bottle (or hand it off to a buddy if time allows). At that point you won't have built up much of a deco obligation anyway so you don't need the deco bottle. If you have a wing failure at the end of your bottom time then you will have used up much of your back gas and will be lighter anyway.

 

[OTF]

For CC diving it’s a bit more complex and there are different philosophies. Mine is that I need to be able to hold a 3m stop neutral with empty wing and dry suit, empty tanks and flooded rebreather (I do not account for the loop lift in order to reduce weight needed and I am willing to flood it in case I need in a bailout situation).

Assuming you're not ditching weight how is that remotely possible? Neuteral with flooded loop AND empty wing/drysuit?

 

[Nick_Radov]

so wearing a weightbelt is unbalanced? Is that the definition? I'm so confused? So it is ok to drop a $1500 canister light, but not 8 lbs of lead in an emergency? Is that the situation?

No one is seriously suggesting dropping canister lights anymore. That was more of a historical thing from back when some tech divers had halogen primary lights with huge 14Ah lead-acid battery canisters which were around 7lbs negative. No one has used those for decades. Modern lithium battery canisters are close to neutral thus pointless to ditch. If you do have to ditch (or hand off) any gear underwater to manage a wing failure then it's more likely to be full stages or maybe other tools.

Having some ditchable lead on a weight belt or integrated pouches can be a good idea in certain circumstances such as open water diving where you might have to float on the surface for a long time while waiting for the boat or swimming back to shore. If you're really in trouble then I guess you can ditch your entire rig and let it sink, but it's easier and cheaper to drop a weight belt. The DAN reports are full of cases where OW divers had a problem at depth and managed to return to the surface, but then failed to establish positive buoyancy and drowned.

 

[LFMarm]

Assuming you're not ditching weight how is that remotely possible? Neuteral with flooded loop AND empty wing/drysuit?

Empty tanks are adding lift

 

[crofrog]

the glock is worn on the right and used as a longhose retainer

Only if you're using a cordless light, otherwise it goes in the right pocket.

 

[crofrog]

There used to be more emphasis on ditchable weight in the past with GUE, and a balanced rig may or may not have included ditchable weight. Newer Fundies courses now seem to concentrate more on proper weighting, redundant buoyancy (drysuit, DSMB), and a balanced rig without the promotion of ditchable weight, but it is still mentioned.

DSMB isn't considered for redundant buoyancy if you need to have enough gas that it requires you to need redundant buoyancy the answer is to use a drysuit.

In my drysuit with my thickest undergarments in salt water the steel tanks with a AL 40 deco bottle has me overweighted with zero lead, what is the balanced rig answer to this?

Yeah, that happens. The drysuit provides redundant buoyancy in the event of a wing failure.

Are you suggesting that having a flooded suit or either kind makes it negatively buoyant? Any water that gets into a suit doesn't make it heavier(until you exit the water)
I had a dive shop owner warn me that if my drysuit flooded, I would drown.

It loses whatever positive buoyancy it was contributing when it floods. Even entirely squeezed my thick undergarments produce substantial positive buoyancy that would go away in the event of a suit flood, which is why it's essential your wing has adequate lift to support the weight of your equipment at the start of the dive, or you have things you can ditch.

So, long story short: yes, you can't dive balanced rig in a thick wetsuit?

Not with large tanks because of the swing of the gas weight

The answer is to use a carbon fiber backplate. If that still leaves you overweighted then trade your back tanks for different ones that are less negatively buoyant. It's not the size of the tanks that matters as much as the buoyancy.

My double 133's have about a 21lb swing from full to empty. There is no way to dive those in a way that doesn't start with you being overweighted if you're going to end the dive 21lb lighter. That's something that people who only dive singles or AL tanks don't have to contend with.