4 deep dives in one day on Duane and Bibb

[stealthtransam]

RJack. Thank you for the comments. You are correct I hope i never have to make a free ascent from 130 fsw.

As for your comments on your psi calculations for turn around no I haven't calculated those yet. I just purchased the 117's. All of my calculations have been based on 80's so if all of my calculations are based on the 80's I should have the added air in reserve on the 117's.

I've performed 12 dives of 100 ft or deeper in the last 1-2 years. 2 of which were last month. I do dive every 2-3 months. So i'm familiar with my breathing rate at 100-130ft on an 80cu tank.

 

[Blackwood]

So i'm familiar with my breathing rate at 100-130ft on an 80cu tank.

So what is your expected depth consumption rate with a 117 at 120'?

 

[stealthtransam]

I dont know what my expected depth consumption rate is with the 117 at 120 yet i'm going to guess 20% lower psi consumption then on an 80 for right now. I plan on going to Blue grotto and doing some studies on my breathing at 100ft on the 117's. right now i burn 100 psi/ minute in heavy current, salt water on an 80. and 150psi/minute at 130ft in heavy current, salt water diving. For mild current/drift diving 80psi/minute at 100ft I have no drift diving numbers to compare at 130ft. so i'm going to base it on my next closest number of 120ft of 125-130psi/minute in fresh water (very calm).

i'm a 190lbs 6ft male i dive 10-14 lbs of lead depending on exposure suit on the AL 80's.

 

[rjack321]

RJack. Thank you for the comments. You are correct I hope i never have to make a free ascent from 130 fsw.

How much deeper are these dives than your comfortable free ascent depth? With only a few mins of bottom time you won't go far from the anchor unless its in one direction with a free ascent.

 

[mk706]

Under the props in the Spiegle you'll get 145fsw. That's beyond recreational limits. Most of the good bits are overhead. Spiegle is a much better technical dive.

Seem to recall the sand at the Duane at about 130fsw.

 

[stealthtransam]

I have no problems with a free assent from 130ft. Every dive with the exception of 3 dives to 100+ft i've have been free ascents.

 

[stealthtransam]

I do appreciate everyones input it does add to my double checking and making sure I have calculated every variable that I can. Thanks all for the comments. It is nice to know there are other people out there that do there math before a dive.

This really was just me looking for a good software program to check my math on and maybe make it easier to play with the variables. i've love to see a good program for me to put in my tank size, air consumption rate, O2% dive depth and have it spit out the options for the day to give me the most even diving though the day =) I also dive my computer but it's it's always best practice in my own opinion do work it out on paper and bring a dive slate with for deep dives as a backup and a sanity check.

last time i hit sand on the speigle was 127fsw at the port rear side. I was looking for the prop =)

 

[rjack321]

I do appreciate everyones input it does add to my double checking and making sure I have calculated every variable that I can. Thanks all for the comments. It is nice to know there are other people out there that do there math before a dive.

This really was just me looking for a good software program to check my math on and maybe make it easier to play with the variables. i've love to see a good program for me to put in my tank size, air consumption rate, O2% dive depth and have it spit out the options for the day to give me the most even diving though the day =) I also dive my computer but it's it's always best practice in my own opinion do work it out on paper and bring a dive slate with for deep dives as a backup and a sanity check.

last time i hit sand on the speigle was 127fsw at the port rear side. I was looking for the prop =)

I have no idea what your definition of "even" is. But really, there are classes on how to make these plans so you aren't just riding your computer. There's no magic software that understands all your tradeoffs. Its pretty clear these dives are way beyond your planning capacity. But with 50-100 dives you probably don't wanna hear that since you've gotten away with 12 other "deep" dives in the last 2 years.

 

[Blackwood]

I dont know what my expected depth consumption rate is with the 117 at 120 yet i'm going to guess 20% lower psi consumption then on an 80 for right now. I plan on going to Blue grotto and doing some studies on my breathing at 100ft on the 117's. right now i burn 100 psi/ minute in heavy current, salt water on an 80. and 150psi/minute at 130ft in heavy current, salt water diving. For mild current/drift diving 80psi/minute at 100ft I have no drift diving numbers to compare at 130ft. so i'm going to base it on my next closest number of 120ft of 125-130psi/minute in fresh water (very calm).

i'm a 190lbs 6ft male i dive 10-14 lbs of lead depending on exposure suit on the AL 80's.

If you know in an 80, you can calculate it for any other tank. Then you can giggle test that against whatever your NDL methodology says, and figure out when to turn back to the upline in order to avoid a free ascent.

 

[MauiScubaSteve]

oops, double, sorry