Wing size for 5mm wetsuit aluminum 80

[cool_hardware52]

Measuring the buoyancy of my wet or dry suit did nothing to get my weighting with doubles sorted out. Getting in the water fully geared up and checking to see what weight I needed did.

It would have if you understood the concept. A pretty miseriable day (by your own discription) could have been more productive had you arrived at the dive site better prepared. Dive days are precious, at least to me. I want to use them well.

I'd also note that Pretty much *every* respondent on you other thread noted you likely overweighted. How did they know?

"Go to a pool and figure out how much weight it takes to sink your wetsuit."

Okay, why not just gear up and get in then see how much weight it takes?

Why not arrive at the dive site already weighted damn close? In water weight checks can be reserved for fine tuning *IF* you know how buoyant your suit is.

Also, how much weight should one take to test the sinking of one's wetsuit? If you can give a ballpark for that, then doesn't that mean you can give a ball park for how much buoyancy the suit provides?

Really? How about *enough* to get the job done....

I meant to ask this before. Doing it that way or your earlier suggestion of putting it in a mesh bag and weighting that both leave me wondering how do you know you've gotten all the air out?

Use reasonable care. If you really can't get the air out test with suit unzipped, and unrolled. You will need a bigger bucket.

Why not put it on, get in the water, burp the suit to let any trapped air out, and see how much weight it takes to sink yourself with it on? Won't that then give you a better number because, one, you know you aren't sinking trapped air, and, two, your number implicitly factors in your personal buoyancy, too?

Apparently you still don't grasp what information is required for wing selection. What we want is the buoyancy of the suit, not the diver. Buoyancy compensators are used to compensate for things that change wrt to depth, and personal buoyancy does not change as long as we are breathing compressed gas.

Personal buoyancy will impact total weighting, but most people greatly over estimate the buoyancy impacts of being a few lbs over their "ideal" weight. "Ya I need 47 lbs of lead cuz I'm a floater" Em, probably not if you aren't Jaba the Hut.

And if you're getting in with the suit to check it, why not get fully geared up? At that point, like Tobin is fond of saying, it's simple arithmetic to work backwards into your suit's buoyancy if you want to. And you are not "estimating" the weight of your rig/pieces/parts.

I've *NEVER* said that. I have posted repeatedly that *once the exposure suit buoyancy is known* weighting is simple integer math.

Is it possible to estimate the buoyancy of a divers exposure suit based on their current configuration? Sure, I'm asked to do so 2-3 times every day.

Doing so has the potential to introduce many errors.

1) Does the diver actually know what cylinders they have been using? A surprising number have no idea, "er, uh you know the regular ones"

2) Was the diver properly weighted to begin with? Most newly minted divers are overweighted.

3) Was the ballast used accurately reported? I have divers that want me to believe they are using 8 lbs with a fluffy jacket, buoyant al 80 and a 7mm wetsuit. They either can't remember, don't know, or are to embarrassed to report they were using 28 lbs.

4) What is the inherent buoyancy of the Jacket / vest BC the diver is using? Can they fully vent it?

Testing the suit eliminates all these error sources, and it often clearly shows the diver that they were over weighted, often grossly over weighted. "So you are 5'10" and 185 lbs, sounds like you are neutral or close to it in your swim trunks. Why then when we wrap you in neoprene that we know to be 18 lbs positive do you think you need 48 lbs of ballast to go diving?" I can almost hear the light bulbs turning on over the phone.

Drysuits unfortunately cannot be tested without the diver, but a few questions about height and weight and fitness will provide a clue about whether you have an diver that may be something other than neutral. Most divers are pretty close to neutral given they make us out of salt water.....

I'd ask, how is the diver harmed by testing their suit and understanding how that impacts their gear choices?

Tobin

 

[dmaziuk]

If you can put it on and get in a pool then clearly that is the best way to do it. I have, in the past, just rolled it up tight, sunk it, turned it a few times and started weighing. Was there a little air in the thing? Maybe but now we are talking a couple of ounces.

I wouldn't be surprised if doing it in the pool gives you far more variance from the gas trapped in your colon than what you get from what's left trapped after sink-roll-turn over a few times in the bathtub. Not to mention how precisely you can actually control the amount of air in your lungs.

 

[gbtech]

So how exactly do you test wetsuit buoyancy? Put it in the mesh bag together with some weights and submerge it in the batch tub?

Thanks

 

[cool_hardware52]

So how exactly do you test wetsuit buoyancy? Put it in the mesh bag together with some weights and submerge it in the batch tub?

Thanks

Roll it up (without trapping a huge bubble) I usually wrap a weight belt around it.

Throw it in the water.

Add lead until it just sinks.

Weigh the lead.

Tobin

 

[OldNSalty]

I wouldn't be surprised if doing it in the pool gives you far more variance from the gas trapped in your colon than what you get from what's left trapped after sink-roll-turn over a few times in the bathtub. Not to mention how precisely you can actually control the amount of air in your lungs.

True. I stand corrected.

 

[halocline]

I wouldn't worry too much about being completely precise when trying to measure the buoyancy of your wetsuit by sinking it in a pool or tub. Just do the best you can. There are lots of little variances with 'exact' weighting needs anyways. If I haven't gone diving in a while, I'll frequently need an extra pound or two on the first dive anyway until my suit and gear gets really soaked.

It's just not that exact. You want to have the minimum weight needed to sustain a stop with an empty wing at 10 ft, and at least for me, that seems to change day to day by a pound or so.

The problem is when divers have no idea and are often 5lbs or more (sometimes a lot more) overweighted. I tend to see this with bloaty-floaty jacket BCs that are far more buoyant at the beginning of a dive than at the end, and often difficult to completely vent. The diver needs much more weight to get down than to stay down. Dive technique is another culprit.

 

[stuartv]

I'd also note that Pretty much *every* respondent on you other thread noted you likely overweighted. How did they know?

True. So, apparently, everyone (else?) was able to give a ball park on required weighting without just kicking it back to me and saying "what's the buoyancy of your suit". And that's with a drysuit. The OP on this thread asked about a 5mm wetsuit and you couldn't give him a ball park answer to his question? You were required to ask him to actually measure his suit buoyancy before you could offer him some help?

What we want is the buoyancy of the suit, not the diver.
...

"So you are 5'10" and 185 lbs, sounds like you are neutral or close to it in your swim trunks..."

So you are comfortable estimating that a diver is neutral(-ish) in swim trunks, but not comfortable estimating the buoyancy of a wetsuit while the diver is wearing it (and nothing else)? And comfortable with determining buoyancy of a drysuit when the diver is wearing it, but not a wetsuit?

Got it.

 

[redacted]

True. So, apparently, everyone (else?) was able to give a ball park on required weighting without just kicking it back to me and saying "what's the buoyancy of your suit". And that's with a drysuit. The OP on this thread asked about a 5mm wetsuit and you couldn't give him a ball park answer to his question? You were required to ask him to actually measure his suit buoyancy before you could offer him some help?



So you are comfortable estimating that a diver is neutral(-ish) in swim trunks, but not comfortable estimating the buoyancy of a wetsuit while the diver is wearing it (and nothing else)? And comfortable with determining buoyancy of a drysuit when the diver is wearing it, but not a wetsuit?

Got it.

A guy asked me for a phone number once. I did not know the number so I gave him an estimate. It did not work very well.

 

[stuartv]

Is it possible to estimate the buoyancy of a divers exposure suit based on their current configuration? Sure...

A guy asked me for a phone number once. I did not know the number so I gave him an estimate. It did not work very well.

LOL

 

[tbone1004]

the issue with doing it geared up, or even just you in the wetsuit, is most divers do not have the ability to exhale completely and not overbreathe which leads to a constant 4-6lbs of being overweight.

Example.
Last week I was working with a bunch of new students during OWT. Due to various circumstances, I was diving VERY overweight. Double PST130's, kydex plate, and a 5mm wetsuit that is ~6lbs positive since it has been crushed. Double 130's are somewhere between 35-40lbs negative when full. This was checkout dives, so everything was kept shallow with quite a bit of it around 15-20 ft. The bubble was HUGE and because of that, I was having to do a significant amount of adjusting vs. that same configuration with a single 72 where I don't need a wing.
If you look at the video you sent me of your valve drill, you are overbreathing quite a bit. If you weight yourself by the math, then you force yourself to learn how to dive in a neutrally buoyant rig. Granted this only works with wetsuits because drysuits are controlled by you, and their buoyancy is a function of how warm you want to be and is a balancing act between your desire to stay warm, and your irritation with dealing with a large bubble. If you breathe like you were in the video while trying to do a weight check in a wetsuit, you would be overweighting yourself. That simple. Most divers can't be trusted to exhale fully and then breathe "normally" i.e. no different that you sitting on the couch when doing a weight check, so doing it as a math problem forces the divers to learn how to actually dive a neutrally buoyant rig, make a table of your positive and negative items and figure out your weighting before you get to the dive site, and if you decide to dive heavy for whatever reason *reasons usually include teaching, working dives, setting anchors, etc etc where you need to be 2-4lbs heavy to assist in somewhat rapid descents*, then you can do it.