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

[PfcAJ]

Who’s telling you this? If you need to ditch some weight, it’s fine.

The example this thread is revolving around is extreme and illustrates why drysuits are preferred.

It means to be properly weighted and not overweighted. If one needs to ditch weights to swim up the diver is overweighted. A heavy wetsuit requiring a lot of weight to descend and necessitating "ditch-able" weights to be able to swim up is unbalanced and a drysuit is recommended.

 

[PfcAJ]

I am not deliberately being obtuse or trying to stir the pot. Perhaps DIR has not defined a balanced rig well. Whether it allows ditchable weight or not (and still be balanced) seems to be unclear, yet to me, this is the most basic of questions.

Also the idea that all (DIR) accidents happen only when diving as a team (apparently by definition) then it makes no sense to worry about carrying too much weight because.. hey your buddy will ALWAYS be there to use his BC to help haul your ass up should your BC fail.. Right? This reliance upon the omnipotent and ever-present buddy is not something that resonates well with me.

It shouldn’t resonate well with you.

You should never be in a spot where you need to rely on your buddy. Buddy aid/rescue is like 2 or 3 steps down the list.

 

[johndiver999]

The need to ditch weights to swim up is by definition an unbalanced rig. Therefore, if a 7mm suit is needed the diver would use the correct tool for the job; a drysuit.

Apparently your definition is not universally accepted.

 

[jadairiii]

The answer is to use a carbon fiber backplate......

Carbon Fiber backplate.....the financial weight alone will sink the poor guy!

Aluminum plates are like, $75.00. Plus it wont implode at depth.....

 

[admikar]

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.

How? 133 is around 3800 liters. For doubles it's around 17lb. Where are extra 4lb coming from?

 

[Nick_Radov]

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.

And this is why we limit back gas weight to something around 15lbs maximum for ocean diving. Either increase the helium content to cut the gas weight, or use lower capacity doubles and bring a stage if you need more bottom gas. Proper mix selection factors in to whether you have a balanced rig or not.

 

[jborg]

How? 133 is around 3800 liters. For doubles it's around 17lb. Where are extra 4lb coming from?

133 * 2 cuft = 7.5 m³
7.5 m³ × 1.29 kg/m³ = 9.7 kg = 21.4 lb

Though you might hope there's some minimum gas involved to make it a little less of a swing, obviously.

 

[rjack321]

Not sure I want to wade into this thread mess but...

It's mathematically impossible if you're diving someplace without a hard floor that functionally limits your thick wetsuit's compression (some bays, lakes or caves)

 

[JoeTPhilly]

Apparently your definition is not universally accepted.

It appears so. It seems it revolves around the ditch-able vs. non-ditch-able weight.

 

[JoeTPhilly]

Who’s telling you this? If you need to ditch some weight, it’s fine.

The example this thread is revolving around is extreme and illustrates why drysuits are preferred

I guess it the GUE Kobayashi Maru...LOL

Maybe I am reading it all wrong. The example appears in Beginning With the End in Mind and Fundamentals course workbook. Below are the numbers. In the book they make mention of ditch-able weights and it seems the diver is good to go by just dropping the 12 pound weight belt as seen below. The Course workbook doesn't have much text so a discussion can take place. The question being what happens when the diver ditches their weight belt at the beginning of the dive with full tanks?

It seems to me what they want a student to get out of it is to be properly weighted and so you wouldn't need ditch-able weights and to also point out in this example a diver would be better off in a drysuit. In fact, the comment was if you need more than a 3mm wetsuit, just dive dry. Am I seeing this wrong?

Thanks for reading.