Optimizing bottom time on repetitive deep dive.

[CuNanoTube]

A few notes. Got it on the using another gas to decompress, there are risks that I (now, obviously oxygen toxicity, dcs due to gas changes, using the wrong mix at the wrong depth, etc. ) "know" about.

I will actually be diving in a 7mm farmer john. This is not an issue as I have never been cold in the suit and the in water times on these dives are small enough that even with the loss of insulation in the suit due to depth I will not be cold.

The dives are rated "advanced" by the club, not the operator.

My father (dive buddy, certified in the 80's, so much more experienced than me) both carry pony bottles ( I carry an 19, he carries a 40), so the rock bottom reserve in our tank is not as vital.

 

[DevonDiver]

I do agree that this does not look like an appropriate dive trip for the OP. However, in his defense only he will know his experience level.

This is a sentiment I fail to understand. How does a novice diver 'know his experience level'? That requires two items of information. Firstly, the divers' capabilites. Secondly, the skill requirement of the dive.

A novice diver posses neither of those.

How can you understand your capabilities, when your actual experience is minimal? Because you 'feel' you are a good diver? That's a confidence issue...and that differs from an educated self-assessment. How can you accurately 'predict' your capacity, when you've never tested it? How do 'you know what you don't know'?

How can you understand the capabilities/skills required by a particular dive? You need experience and knowledge of the risk, the required techniques, the problems that need to be encountered... etc etc.

Most agencies recommend certain limitations for novice divers - especially max depth recommendations that are normally in line with a certification level. At the very least, they recommend conservative, prudent diving practices. They do this because they recognise that novice divers will have severe difficulty in realistically and accurately self-appraising their capacity to conduct dives beyond their thresholds.

 

[rhwestfall]

Me thinks you are talking about the Boland and the Dean Richmond. Been on these, and I wouldn't be doing 4-in-2...... Two dives, long SI between, and no second day or 1 each day. Alternate second dives like the Anna Belle Wilson (less attractive) that are shallower. The Pasaic is 90 to the mud if I remember. Just me, but this isn't being smart..... sorry.

 

[elan]

My father (dive buddy, certified in the 80's, so much more experienced than me) both carry pony bottles ( I carry an 19, he carries a 40), so the rock bottom reserve in our tank is not as vital.

How many failures can you sustain in this configuration and with this gas planning?

What is your B if you overstay on the bottom ?

 

[rongoodman]

Could you rent O2 clean tanks from the shop, so you can use Nitrox?

 

[Jim Lapenta]

If it is the Boland, I believe that is 140 or so to the mud. I love that dive. Did it with 17/26. Nice and clear headed. Also if it is those two at this time of year the temps are around 38-40 degrees F. But going back to the depth no matter what you plan to do you should mix for the bottom just to cover your butt. I won't do any Erie dives with more than 28% in back gas.

 

[ianr33]

If it is the Boland, I believe that is 140 or so to the mud. I love that dive. Did it with 17/26.

Why use a hypoxic mix on a 140 foot dive?

 

[Blackwood]

Why use a hypoxic mix on a 140 foot dive?

Sounds like a bastard mix (maybe partially used 15/ topped off with air) to me. *shrug*

 

[Dive Bug Bit Me]

This is a sentiment I fail to understand. How does a novice diver 'know his experience level'? That requires two items of information. Firstly, the divers' capabilites. Secondly, the skill requirement of the dive.

I suggest a lot depends on what diving the OP has actually done. If he has 49 dives in cold water and the last 15 were to those depths (with his AOW instructor), he probably is in a reasonable position to assess the dive. Additionally he is diving with his AOW instructor on this trip. I presume that the instructor has seen him in the water and formed a view of his skills as well. If my wild assumptions are in fact true, I would say the OP is better placed to assess this dive than I was when I had a mere 49 under my weight belt (even though I was AOW by 20 dives).

Conversely if the OP is on 25 dives and those were all in the Caribbean at 30 ft then this dive is suicide.

I expect reality is somewhere in between, so only the OP will know if he has been to 120 ft in cold water (in a supervised capacity). If this trip will be comprised of 4 pinnacle dives in succession it is a stupid undertaking.

 

[rhwestfall]

I love that dive. Did it with 17/26.

But what else did you do that day? That answere his question better. Hoping to see it again this summer. Boat will be out of storage soon, and gear is ready..... come on summer!!!!