4 deep dives in one day on Duane and Bibb

[MauiScubaSteve]

The Wreck of the Duane

The mast and crow’s nest, protruding high above the hull, can be seen at 60 feet. At 70 feet, just forward of amidships, is the navigating bridge. The superstructure deck is at 90 feet and the main deck lies at l00 feet.

FWIW, My log book shows the main deck of the Duane as 108 fsw, and my AOW Instructor had written permission from PADI to conduct the Deep Dive to the Duane's deck. I have made a number of dives on the Duane, and never bothered to go below the main deck; I would have if a bull shark or goliath grouper had been down there. There was a bull shark at the sand (~120') when I was solo diving a Draeger Dolphin rebreather, but I had promised the Captain I would not go below the main deck, so I did not go below the main deck.

USCG Bibb - Key Largo SCUBA Site - Dive Spots

In 1987, the Bibb and another cutter, the Duane, were stripped and prepared for sinking. The doors above the main deck were removed, but the hull was sealed. The Bibb rests on her starboard side in 130 feet of water. The port railing can be reached at 95 feet.

FWIW, my computer registered 137 fsw, laying in the sand for the Bibb grouper picture below (LP95, 28% mix).

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If we are talking PADI tables, and EAD, touching the sand at the Duane (~120') on 28% means a max dive time of 16 minutes. If you did indeed reach the max time (M), after an hour you are group D, giving a 15 minute max dive time for the deck on 32% (~110').

After a 2 hour lunch you are group B, so "just above" the sand at the Bibb means max dive time on 28% is 8 minutes. Then after an hour a 60' max depth dive on 36% could be up to 42 minutes. All of that is contingent on my math being right, and probably lunch will be longer than 2 hours.

Personally, if I were you I would plan on NOT going below the main deck of the Duane on the first dive (~110'), staying above the main deck on the second (~90'), diving 32% on both Duane dives, then 28% on the Bibb and 36% on the final reef dive. I personally see no problems with conservatively riding my computer.

If a bull shark or goliath grouper were sand level at the Duane, I would make an gentle photo foray and let my computer figure out the numbers. That would not violate my training as my Advanced Nitrox training, shortly after taking the pictures above, is ppO2 1.6/1.8. That also means I now have no issue with 32% on the Bibb, but current might keep me from going all the way to the sand.

 

[stealthtransam]

Rjack... Thank you for your opinion... I understand you have 1000+ dives under your hat. But I do not feel you have any knowledge on my scuba education nor what classes I have taken. I am no expert now are diving the wrecks in the FL keys new to me. I have in fact taken classes on wreck diving, deep diving, and dive planing. I see the point of this thread did not in fact emphasis that I was not just looking to "ride my computer" I am doing the math both in advance ensuring it with multiple ways to double check it. Many months in advance at that.

I will restate that the purpose of this thread that I have started has nothing to do with my preparation skills or how many more dives I plan on doing before July when I dive this charter as well as test out my new tanks and characterize them. This thread was started to ask for a tool to compare my hand calculated values against another method. If anything I feel that my due diligence is very high on this. And I take my safety in very high regards.

 

[stealthtransam]

halemano Thank you for the photos. I'm guessing your times were based on a 1.6 pO2? My numbers came out considerable more conservative. I came out with 10/10/7/ but i was using 1.4pO2 and rounding down on the PADI tables.

FYI I shoot a similar camera i shoot the Oly 4000 in the PT-010

 

[mk706]

stealthtransam, you sound like a tech diver in the making. Why not knock out a couple courses while you're down there and do those sites right?

 

[stealthtransam]

MK thank you for the comment and suggestion. I'm actually already in the process of researching and signing up for some tech courses with local dive shops but i want to finish my rescue courses first. I am also certified with the Red cross for numerous training.

My open water instructor was was a navy dive instructor and has egged me on to tech diving for some time now. my dive buddy for the last 4 years was a Marine as well so I think he's interested as well in tech. so water and diving run deep in my group of friends.

 

[stealthtransam]

halemanō is your bail out bottle a 30 or 40?

 

[mk706]

No need for another thread on stage bottles. They should only come in two sizes: 40 & 80. Especially if you're going to grow into tech.

Key Largo is one of the best areas to train for tech. Highly recommend working through Silent World. Chris and his staff offer a full line of dive instruction, but their passion is clearly tech (particularly rebreathers). Chris has instructors from GUE, IANTD, TDI & PADI-TEC. Great to learn with an instructor who teaches new tech students a couple times a month.

 

[stealthtransam]

The keys are only a few hour drive for me so I'll keep Silent World in mind for later this year or next year. Thanks MK

 

[MauiScubaSteve]

halemano Thank you for the photos. I'm guessing your times were based on a 1.6 pO2? My numbers came out considerable more conservative. I came out with 10/10/7/ but i was using 1.4pO2 and rounding down on the PADI tables.

(123 + 33) x .72/.79 - 33 = 109.2' (EAD of 123' on 28%)

So for all intensive purposes, the sand at the Duane on 28% is like the deck of the Duane on air; rounding for the tables would be 110' which an old PADI RDP gives 16 minutes as the NDL, pressure group M.

An hour later, PG is D. Next dive going no deeper than the deck...

(108 + 33) x .68/.79 - 33 = 88.4' (EAD of 108' on 32%)

Old RDP from above has 15 minutes for 90' repetitive NDL; ending pressure group Q.

Two hours later, PG is B. Next dive max depth 132'.....

(132 + 33) x .72/.79 - 33 = 117.4' (EAD of 132' on 28%)

RDP shows 8 minutes for 120' repetitive NDL; ending pressure group K.

123, 108, 132; 1 hour, 2 hours, 1 hour; 28, 32, 28, 36

1.4 at deck of Duane on dive #2 and at sand of Bibb.

 

[stealthtransam]

yours and my RDP is slightly different but I pulled up one on line and it seams like your going to the black. I was going to the last grey to not push it, and 1 hour puts me into group C on my RDP. I also was looking at doing 28 on all 3 dives as to hopefully not mix gasses. I like your math better then mine thought I have to say. It's something to think about. I've never dove with this dive shop before and the blends will be hot fills so until I get the tanks back and analyze them for the first day of diving i might stick with my original idea of 28's on all 3 dives