Diving Performance - Beyond Drag (article Series And Discussion)

[ronscuba]

Standard aluminum 80's at all the different places I've dove.

I probably could dive without the wing when I don't wear a wetsuit. I put air in at the beginning of the dive, basically vent everything towards the end of the dive. According to my calculations, the tank and my gear swings from -4 to close to neutral when the tank goes from full to 500 psi.

I am one of those people when wearing just a bathing suit, will sink if I exhale. I am on the lean side. It's not that out of the ordinary and nice diving without weight. Makes buoyancy control much easier. I think what makes me odd is, I don't wear a wetsuit. If you got rid of the neoprene, you would see a lot more people like me.

 

[dumpsterDiver]

Being thin does not affect your need for a BC..If you were fat, you might need to wear some lead, but you would have no increase in weight swing during the dive. and... you might even be safer, because you would have some ditchable lead in an emergency..LOL.. say like an underwater heart attack..

 

[REVAN]

I am one of those people when wearing just a bathing suit, will sink if I exhale.

Same with me. Full lungs, I float with most of my head above water. Full exhale, I sink. I am neutral with about 1/4 lung full. This means that I want my kit and everything I'm wearing to be neutral at 15 to 20 feet depth when the tank has about 500 psi remaining (this is assuming that I will be diving at depths greater than 20 feet for my planned dive). If there is no compressible neoprene like materials in any of that gear, the depth dependency is removed from the buoyancy considerations.

If divers used these guidelines for weighting, only the tech divers would have a use for a BC with more than 10 pounds lifting capacity. Many divers wouldn't need a BC, and the ones that use them could have a much smaller and more streamlined kit. I estimate my ideal BC would be an 8 pound system (about half of your BC), and I'd only wear that when diving my 6mm wetsuit.

 

[ronscuba]

Deep Sea Supply sells a 12 lb wing. It is designed for back mounting, with the tank slung. I imagine you could come up with a way to wear it in the front similar to Johns BCD, so you can mount the tank on the back of the plate.

 

[fjpatrum]

Wow, interesting turn to this thread. Thanks, @John C. Ratliff for stepping into the discussion.

 

[ronscuba]

fjpatrum, where do you typically dive and what kind of gear/fins do you have ?

 

[Doc Harry]

Revan, your assumption that speed is good is wrong. All wrong.

 

[REVAN]

Revan, your assumption that speed is good is wrong. All wrong.

I'll counterpoint that statement with the overwhelming evidence that nature disagrees with you, not me.

 

[Reku]

In regards to the Christmas tree discussion and drag.

I've got ... 10 D rings, 1 circle ring, 1 double ring, 2 door handles on my sms75 - 2 on each hip spaced apart at 0, 45, 135,180 degree points (for floaty AL tanks) 2 on each shoulder (bottom set is for backgas tank chokers and deco tanks, top set is stage tanks and reg/inflator clip offs). The middle circle ring holds the bungee loop retainers. 1 butt d ring for safety/jump reels, lift bag. 1 front D ring for the scooter attachment.

And then there's that weird double ring on the back used to butt mount my canister and hold the dsmb, smb and wreck reel. The door handles only are used to hold backgas/deco/stage tank leashes.

So in my case I have a lot of D rings/clip off points BUT they all have exact purposes - they are not just to hang random stuff from - I don't carry random stuff - everything else goes in my pockets: tables shears, jon line, etc.

If I didn't SM AL tanks every so often I would only have 6 D rings. Drag is minimal when I am setup to sidemount correctly - no one wants to get snagged on a random rock in highflow cave....or on a sharp edge of a wreck ... been there done that - it sucks.

To each their own I suppose - YMMV.

 

[REVAN]

To be clear, the comment was that the gear that has the tech look can allow someone to attach a lot of equipment to become a "Christmas tree Diver", by virtue of having a lot of D-rings. Not that a Tech diver is a "Christmas tree Diver".

In my view, tech diving involves great thought toward assembling equipment appropriate to doing the dive that is being attempted and training to be able to efficiently use that equipment under the conditions of the dive to mitigate risk to acceptable levels. There is nothing haphazard about it.

However, even without going the "Christmas Tree" rout, Tech has become something of a fashion. There are some divers that are drawn to the cool looking equipment without addressing the issue of using "the right tool for the job". Evidence can be found here on SB with posts like this: Treat every dive like a tech dive

Just because the mountain climbers that go to the top of Everest look cool in their gear, that's no reason to dress like them with crimps, packs, O2, etc... when going for a walk around central park. That's reductio ad absurdum, but I think it helps drive my point that recreational divers would be better served with gear that looks more like my setup than a kit designed for diving the Andrea Doria.