Using a pony. Mix?

[Colliam7]

What is special about those 3 particular U-boats that makes them "The Trifecta"? There are more U-boats sunk along the coast. I know of the U-1105 and U-853, at least.

Think about it - I am in NC. There are three diveable U-boats off the NC coast, all sitting where they ended up after being sunk in hostile action. People coming to my office, in NC, could more readily relate to something off the NC coast than they could to a boat off the Rhode Island coast, or something that had been sunk, then raised, repositioned, sunk again etc, up in MD. I would like to dive the 853 as a matter of fact.

 

[Lorenzoid]

I specifically said "change to my pony, for whatever reason" on purpose - so as to not give any basis to just assume I ran out of gas. I was specifically thinking of other possibilities like 1st stage failure or a blown HP hose.

My comment was in response to westfall's comment about a scenario that included running out of no-deco time at the same time as having to switch to the pony.

 

[stuartv]

Think about it - I am in NC. There are three diveable U-boats off the NC coast, all sitting where they ended up after being sunk in hostile action. People coming to my office, in NC, could more readily relate to something off the NC coast than they could to a boat off the Rhode Island coast, or something that had been sunk, then raised, repositioned, sunk again etc, up in MD. I would like to dive the 853 as a matter of fact.

Gotcha. I gather that those are the only 3 off NC that are diveable and sunk in action. That makes sense. Are those 3 plus the 2 I mentioned the only diveable U-boats on the whole East Coast?

 

[rivers]

U-869, but that's not a recreational dive

 

[stuartv]

answering your question with another: What is your gas plan for this (you and your buddy)? What are the reserves and how are they managed?

If you want to ride that NDL that tight, you should have a lot more into a plan than "I'll switch to my pony"... as said right after my post, you are realistically bordering a technical dive.

What is the deco requirement (and the quantity of gas needed) if you trip that NDL? Do you have have it?

Your earlier post pretty strongly implied that there is NO dive plan that would work given the 3 parameters I originally posited (depth, time, gas mixture), so why don't you justify that instead of trying to get me to throw out some half-thought-through plan that you can poke a hole in and use to vindicate your insult?

Doing some quick calculations, based on my average SAC from my last few dives (i.e. calculating based on RMV of .6 cu ft/min), it looks like I would consume 92 cu ft of gas. Are you suggesting that there is no safe Rec dive plan that involves using 92 cu ft and getting out with an adequate reserve? Because, otherwise, your "nice dive plan" passive-aggression just comes across as implying that you think I'm too stupid to develop such a plan.

Now, obviously (well, it's obvious to me, anyway), whatever plan I dive with would include "if I use my air faster than I planned for, then I'll get out sooner." Is there something wrong with making a plan based on a best-case for air consumption and then vetting it and planning contingencies for worst-case consumption also? E.g. "I'll assume SAC=.6 and plan to stay down for 29 minutes. But, if I'm down to 1000 psi after 15 minutes, then I'll start my ascent immediately."

---------- Post added February 27th, 2015 at 02:08 PM ----------

U-869, but that's not a recreational dive

I see that that is in 240' of water. Okay, I'll put it on my list for last, after I dive the other 5 and have a few hundred dives and a crap-ton more training in my log.

 

[rivers]

Your earlier post pretty strongly implied that there is NO dive plan that would work given the 3 parameters I originally posited (depth, time, gas mixture), so why don't you justify that instead of trying to get me to throw out some half-thought-through plan that you can poke a hole in and use to vindicate your insult?

Doing some quick calculations, based on my average SAC from my last few dives (i.e. calculating based on RMV of .6 cu ft/min), it looks like I would consume 92 cu ft of gas. Are you suggesting that there is no safe Rec dive plan that involves using 92 cu ft and getting out with an adequate reserve? Because, otherwise, your "nice dive plan" passive-aggression just comes across as implying that you think I'm too stupid to develop such a plan.

Now, obviously (well, it's obvious to me, anyway), whatever plan I dive with would include "if I use my air faster than I planned for, then I'll get out sooner." Is there something wrong with making a plan based on a best-case for air consumption and then vetting it and planning contingencies for worst-case consumption also? E.g. "I'll assume SAC=.6 and plan to stay down for 29 minutes. But, if I'm down to 1000 psi after 15 minutes, then I'll start my ascent immediately."

---------- Post added February 27th, 2015 at 02:08 PM ----------



I see that that is in 240' of water. Okay, I'll put it on my list for last, after I dive the other 5 and have a few hundred dives and a crap-ton more training in my log.

But how much gas would you need to get 2 divers to the surface with a stressed SAC rate from the most critical point in the dive (on the bottom) while completing any and all stops? If you're diving as a buddy team, that's really the best way to calculate how much gas you should have in reserve.

 

[rhwestfall]

Perceive the intent as you wish, no malice intended. Likely would have been an interesting discussion around a table where body language and other factors are seen......

To me, critical thinking, and exploring the root of the problem for resolution is more important. Planning (and/or mitigating) from there starts you on the clearer path, or exposes areas in need of additional investigation.

 

[dumpsterDiver]

Your earlier post pretty strongly implied that there is NO dive plan that would work given the 3 parameters I originally posited (depth, time, gas mixture), so why don't you justify that instead of trying to get me to throw out some half-thought-through plan that you can poke a hole in and use to vindicate your insult?

Doing some quick calculations, based on my average SAC from my last few dives (i.e. calculating based on RMV of .6 cu ft/min), it looks like I would consume 92 cu ft of gas. Are you suggesting that there is no safe Rec dive plan that involves using 92 cu ft and getting out with an adequate reserve? Because, otherwise, your "nice dive plan" passive-aggression just comes across as implying that you think I'm too stupid to develop such a plan.

Now, obviously (well, it's obvious to me, anyway), whatever plan I dive with would include "if I use my air faster than I planned for, then I'll get out sooner." Is there something wrong with making a plan based on a best-case for air consumption and then vetting it and planning contingencies for worst-case consumption also? E.g. "I'll assume SAC=.6 and plan to stay down for 29 minutes. But, if I'm down to 1000 psi after 15 minutes, then I'll start my ascent immediately."

---------- Post added February 27th, 2015 at 02:08 PM ----------



I see that that is in 240' of water. Okay, I'll put it on my list for last, after I dive the other 5 and have a few hundred dives and a crap-ton more training in my log.

A SAC of 0.6 is pretty low for a new diver in cool water, thick suits, currents and kicking. I'm not saying it is wrong, but planning for a SAC of 0.8 or so, might be better. A lot depends on what kind of conditions you were in before to generate the Sac estimate of 0.6.. I know I go over 0.8 sometimes.

 

[TONY CHANEY]

Your earlier post pretty strongly implied that there is NO dive plan that would work given the 3 parameters I originally posited (depth, time, gas mixture), so why don't you justify that instead of trying to get me to throw out some half-thought-through plan that you can poke a hole in and use to vindicate your insult?

Doing some quick calculations, based on my average SAC from my last few dives (i.e. calculating based on RMV of .6 cu ft/min), it looks like I would consume 92 cu ft of gas. Are you suggesting that there is no safe Rec dive plan that involves using 92 cu ft and getting out with an adequate reserve? Because, otherwise, your "nice dive plan" passive-aggression just comes across as implying that you think I'm too stupid to develop such a plan.

Now, obviously (well, it's obvious to me, anyway), whatever plan I dive with would include "if I use my air faster than I planned for, then I'll get out sooner." Is there something wrong with making a plan based on a best-case for air consumption and then vetting it and planning contingencies for worst-case consumption also? E.g. "I'll assume SAC=.6 and plan to stay down for 29 minutes. But, if I'm down to 1000 psi after 15 minutes, then I'll start my ascent immediately."

Stuartv, I do not know several of the divers that have posted and I am sure that I do not know westfall but I feel that you might want to read his post again. He (I guess) is trying his best to give you some very good free advice. Please take some time time to dissect what he just told you. I really know of no "tech diver" and yes you are pushing into that area, that plans their gas on their best SAC rate. There is no ideal / best SAC rate when facing serious situation as free flows, high flow caves, currents, buddy freaking out, working, gas used for drysuits, lift bags, etc. If you double your SAC rate and then look at the numbers you will, more than likely, be taken back a step at the amount of gas REALLY needed...even if you do not use it. It is really a true situation of needing it and not having it compared to needing it and not having it. Several of have said that we would not push the NDL that close without proper training.

What we or most are trying to say is we care about you and trying to help. So if you want to continue down the path that you are asking about then feel free to do so...there are no police down there. Please do not take this as I am coming down on you....we all have learned and would rather assist you on the surface (internet) that at depth or at the hospital. Please take from us and question yourself. "If I have seen further it is by standing on the shoulders of Giants." Sir Newton

 

[Colliam7]

Is there something wrong with making a plan based on a best-case for air consumption and then vetting it and planning contingencies for worst-case consumption also? E.g. "I'll assume SAC=.6 and plan to stay down for 29 minutes. But, if I'm down to 1000 psi after 15 minutes, then I'll start my ascent immediately."

OK, a reasonable question, and - for me at least - the answer is, 'Yes, there is something wrong with it.' The dive 'mission' should be defined on the basis of how much time you can reasonably expect to spend at depth (among other things). While 'mission' is usually associated with technical diving, it really is, or should be, part of good recreational dive planning as well. If you set a mission goal on the basis of an optimistic SAC, there may be a psychological impetus to stay 'just a few minutes longer' in order to do what you planned, rather than begin your ascent when you realize that your gas supply is being consumed faster than anticipated. Admittedly, that is a 'soft' assessment - a disciplined diver would, of course, never find them selves doing that. But, it is that very diver behavior that gets people in trouble, i.e. trying to do too much during a dive and putting themselves on the edge of safety to do it.

In fairness, other divers may firmly disagree with my view on this, and I would accept that my view may be on the very conservative end of the spectrum. But, I believe, I practice, and I teach, that it is better to plan for the worst (higher SAC being a good example) and then be pleased when conditions are somewhat better than expected, than to plan for the best and have to react during the dive to conflicting priorities and unanticipated circumstances.
---------- Post added February 27th, 2015 at 02:08 PM ----------

Gotcha. I gather that those are the only 3 off NC that are diveable and sunk in action. That makes sense. Are those 3 plus the 2 I mentioned the only diveable U-boats on the whole East Coast?

As rivers mentioned, the U-869 is dievable, for those with technical training. I am not aware of others beyond those 6.

Let us know what U-boat your class dives on - given your location I presume the U-1105 is the closest. I'd be curious about your overall experience after the class is finished.