Buoyancy Plan

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PoPo Diver

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Ok guys and gals, I have an idea and I want to vett it first.
I’ve got a dive Saturday, the first one back in the water in 130 days. So the first dive will be a weight/bouyancy check and skills drills. That being said, pre-winter I was close to the elusive “hover”. So here’s my plan:

Using my full kit (drysuit, AL80 twinset, etc), I’m thinking about putting a stage bottle on the platform at 20 feet. I’ll bleed my back gas to 500 PSI, and breath off the stage to get the weight check, in full kit, with the 500 PSI most literature recommends. I’ll have two team mates with me if something happens outside of the plan and the stage is a fresh tank. Has anyone ever done or seen something like this? I’m not a fan of doing weight check at the end of the dive for a couple reasons, mostly Bc I don’t wanna fight my position and trim during the dive when I could be hammering essential skills.
 
Your plan will work. However, I find it easier to use full tanks, weight for eye level, then add 10 lbs to compensate for the weight you'll lose taking those 2 tanks to 500 psi.

Edit: You can also do this at depth with a full tank if that's where your pile of weights are. Setting the total weight should be quick, so no appreciable change from breathing. Again, get neutral with a full tank, empty BC, and desired amount of suit squeeze; and then add 10 lbs.

FWIW, that is actually 2x the typical reserve of 12.9 cuft (500 psi in a single AL80). Your call, of course.
 
I’m not a fan of doing weight check at the end of the dive for a couple reasons, mostly Bc I don’t wanna fight my position and trim during the dive when I could be hammering essential skills.

I would say trim IS an essential skill. Use the stage if you want, but there's no need to drain your tanks to set trim.
 
Put 750 in your back gas, dive the stage attached to you. Dial in your trim, then ditch the stage and finalize your buoyancy. A full stage is maybe 3 pounds negative (assuming its a Alum 80, which it should be)

The stage gives you all the time to get comfortable again, then, once ditched you have 250 psi to dial in you buoyancy, which at 20', should give you plenty of time. The added benefit is you get to practice with the stag too. Fun day for all!
 
Ok guys and gals, I have an idea and I want to vett it first.
I’ve got a dive Saturday, the first one back in the water in 130 days. So the first dive will be a weight/bouyancy check and skills drills. That being said, pre-winter I was close to the elusive “hover”. So here’s my plan:

Using my full kit (drysuit, AL80 twinset, etc), I’m thinking about putting a stage bottle on the platform at 20 feet. I’ll bleed my back gas to 500 PSI, and breath off the stage to get the weight check, in full kit, with the 500 PSI most literature recommends. I’ll have two team mates with me if something happens outside of the plan and the stage is a fresh tank. Has anyone ever done or seen something like this? I’m not a fan of doing weight check at the end of the dive for a couple reasons, mostly Bc I don’t wanna fight my position and trim during the dive when I could be hammering essential skills.

Another option is to search for and review the buoyancy swing for your tanks, weight yourself to be more or less neutral with full tanks and then add the extra weight to compensate for the buoyancy swing.

Check this sheet for tank buoyancy swings: SCUBA Cylinder Specifications – Huron Scuba, Snorkel & Adventure Travel Inc. PADI 5 star IDC in Ann Arbor, MI
Or this sheet: Updated SCUBA tank specifications list -- in PDF and spreadsheet

Heads up, if you have Luxfer S80s as your tanks, in TMassey's sheet (second link) you should look at the Neutral 80s. If I recall correctly, Luxfer switched the designation of their neutral 80 to S80 years ago. Using the Luxfer S80 from the Huron Scuba Sheet as an example, there's about a 5lb buoyancy swing for each tank, so once you get neutral with full tanks, just add an additional 10lbs like another poster suggested.
 
Another option is to search for and review the buoyancy swing for your tanks, weight yourself to be more or less neutral with full tanks and then add the extra weight to compensate for the buoyancy swing.

Check this sheet for tank buoyancy swings: SCUBA Cylinder Specifications – Huron Scuba, Snorkel & Adventure Travel Inc. PADI 5 star IDC in Ann Arbor, MI
Or this sheet: Updated SCUBA tank specifications list -- in PDF and spreadsheet

Heads up, if you have Luxfer S80s as your tanks, in TMassey's sheet (second link) you should look at the Neutral 80s. If I recall correctly, Luxfer switched the designation of their neutral 80 to S80 years ago. Using the Luxfer S80 from the Huron Scuba Sheet as an example, there's about a 5lb buoyancy swing for each tank, so once you get neutral with full tanks, just add an additional 10lbs like another poster suggested.

I just sold a set of neutral 80s that were born in 2016. They have the N designation still. So possibly newer than that they changed it
 
https://www.shearwater.com/products/teric/
http://cavediveflorida.com/Rum_House.htm

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