Posted by MHK on January 04, 2001 at 10:35:29:
In Reply to: The Cosmology of DIR on the West Coast - Part 3. posted by seahunt on January 03, 2001 at 22:22:55:
Seahunt,
Let me start by saying that I appreciate the thorough and thoughtful analysis. As you may imagine I have an alternative viewpoint but I believe exchanges of this nature are healthy..
Overall I agree with your comments with respect to definitions that can be used for purposes of discussion, I agree that the certification agaencies, absent GUE, caters to the lowest common denominator and then I'll provide my thoughts..
I come from the mindset that DIR is applicable to ALL forms of diving even though it derives it's roots from the technical and cave diving communities and I simply don't find your arguements compelling to dispell my beliefs for the reasons that I will setforth below, but it is useful from my perspective to atleast gain a better understanding of your thoughts..
I'll also add a minor disclaimer with respect to my essay respecting DIR as it relates to recreational diving. The essay was intended to provide a *brief overview* and was not intended to be all encompassing. Very often new posters come on one of the various scuba forums and ask what is DIR so I thought I'd simply put together a boilerplate answer. JJ will be releasing in the next month the *official* DIR book relating to recreational diving.. When I was with JJ over Thanksgiving I peeked at the drafts and I'm leaving tomorrow for Florida for 10 days and JJ has requested that I review the final draft before print. It is approximatley 100 pages so my sense is that the level of detail that you seek that was lacking in my essay will be detailed appropriately.
Notwithstanding the foregoing, let me address your comments for clarification..
No deep air - I have posted often that we recommend Nitrox for dives above 100' and then trimix from 100' and deeper. And as for your comments about SoCal diver's rarely going deeper than 100' I STRONGLY disagree. I'll site for example Farnsworth Bank, USS Moody, Caissons, Ship Rock, oil rigs just to name a few.. It happens with alarming frequency. Bear in mind that I recognize your comments with respect to the 100' - 130 range and while I believe it is safer to use trimix in those depths I could just as well understand the use of Nitrox in the 100' - 130' range..
Using the proper mix for the dive-
I'm not sure how you do not recognize this as a issue directly applicable to California diving. This suggestion transcends geographic borders. As I noted above, all too many divers are diving much deeper than recreational limits and are doing so with improper bottom gas and no deco gas.. This analysis applies equally well to your commenst respecting EAD's and EAD's at 100'.. I'm not sure how often you go on the commercial boats ( I'll note that I'm on them every weekend ) and I see various clubs, shops and open boats and without exception there are always diver's that exceed recomended limits..
Unified team concepts we have beaten to death ad nausem so a re-hash here probably isn't productive and moreover isn't an issue unique to California diving.. One either accepts or rejects the buddy system.
Limiting your P02's to 1.4 probably has more of an application in the technical environment I'll stipulate, but my hope is that more and more diver's will look to Normoxic or Hyperoxic trimixes in the very near future and this point is important. Particularly in light of the fact that PADI will introduce it's new HotX program at DEMA the end of this month.. PADI mass marketing campaign for Trimix use will certainly result in more diver's using hyperoxic mixes.
Increased pre-dive preparations involves several components that once again apply very well to California.. As you note viewing conditions, but also reviewing and maintaining gear, dive profiles and contingency planning. For example, if you read Terry May's New Years day trip report about the Palawan. We had a team of divers that for the 1st 2 dives of the day didn't come up any where near the Great Escape and had very long surface swims back. On the last dive very fortunately they came up the anchor line because we had a fog back move in after the divers entered the water. The fog was so thick that you couldn't see from bow to stern. Had these two diver's did the same thing on dive 3 that they had done all day they would have never found the boat and contingency planning and pre-dive preparation would have been of tantamount importance. ( ie; whistles, flares, surf mats and the like )...
Incorporating deep stops..
This is one of the most important advances in decompression analysis in the last couple of decades and can very well be backed up. All the research has been published and is there should you so desire.
The general rule of thumb with respect to deep stops deep stops relate to recreational diving is that you cut in half your maximun depth and your first required stop. So for example in most recreational profiles 15' for 3 minutes is the rule of thumb. So if you did a 100' dive you would build 30 second stops in at 10' increments beginning at 40' ( 100' - 15' = 85' then divide that by 2 = ~42'). BTW, the notion of deep stops is widely accepted and is very clearly applicable to California. Decompression algorithms are not an exact science and almost without exception all the leading decompression modelers accept this premise.
As to physical fitness I would urge you to reconsider your viewpoint particularly when a diver surfaces very far from the boat, down current nad has a huge surface swim back.. Furthermore, the benefits of physical fitness of course decrease your air consumption and thereby allow for extended bottom times among other decompression benefits. Why doesn't this apply to Calif????
Minimalism and streamlinning _ as to reduction of drag for game bags, I'm not sure DIR has an answer for the coefficients of drag issues relating to game bags ;-)
But your comments about not being revolutionary is noted. We often say that DIR isn't all new nor is it a concept whose ideas are all invented by JJ or George. DIR has eveolved ( and continues to evolve on a daily basis, I'll speak to that point later in my analysis ) as a result of many ideas from many pioneering diver's.
And the solo diving comments we'll just have to agree to disagree on..
Perhaps I see DIR through rose colored glasses and strangly believe that not only is DIR applicable to California recreational diving but it is in point of fact desirable.
I still havent seen in your analysis an overall, big picture detriment to DIR. While you have putforth your beliefs that it isn't applicable, and I've supplied my comments with respect to why it is, you haven't made the case, atleast in my mind, that a diver in Calif. diving DIR is somehow compromised.
Furthermore, I'd like to spend a little time on the notion that I posed in another post about if I don't need something at 400' you should at 60'.
Let's look at that..
Obvioulsy a diver doing a dive to 400' warrants advanced contingency planning and adequate redundancy. It therefore stands to reason that that diver would require more, not less, than the diver doing a recreational 60'. So why I posed my question the way I did is because if I don't need it at 400' it's a pretty easy leap of faith that it probably isn'y needed at 60', and I'd invite you to indicate something that is needed at 60' so we can discuss specifics...Accordingly, the DIR approach to minimalism and streamlinning stands on it's merits. If you take away the additional gas and deco gas needed at 400', my rig is the exact same rig at 60' and it provides me everything that I need.
The old adage that necessity is the motherhood of invention comes to mind with respect to DIR. As we noted DIR was developed in the Florida cave system.. The reason was that it was a direct result of the alarming number of fatalities occuring in the cave systems which caused landowners to preclude diver's from entering the caves, it also caused government intervention and made the diver's themselves more attentive to their diving habits.
In today's world, diver's are no longer properly or adequately taught to dive. They are handed a CD-Rom told to view it, given a few lectures and are sold a C-card. I wholly note that in your analysis you keep talking about California diver's as if they are all taught how to dive in our waters. Take for example the tourist that learns how to dive at Club Med or in Cayman and then doesn't do a dive for years then decides to get on a boat out here. By your own admission California has it nuainces that require additional attention, do you believe this hypothetical diver is capable??? It appears that the German tourist that perished last week on the Yukon falls into such catagory..
I'll also note for the record that DIR is constantly evolving and the leaders of the DIR movement are continually trying new things to come up with better and safer diving practices. I would imagine that George and JJ and several other noteworthy DIR advocates spend more time that anyone studying new gear, working with designer's to modify and improve gear. It was surprising to me that when I decided to convert to DIR I spent a fair amount of time with George and JJ and every time that I posed an idea that I thought could improve DIR and brought it up, not only had they thought of it already, tried it already but could give me 2 or 3 reasons why DIR was better. This is a very important point as the DIR movement gains speed. There are many people who proport to be DIR so my comment has always been if they can't tell you WHY they do something than I would be mindful of their advise and comments. It's one thing to know HOW to do something but the WHY is more important than the HOW. It speaks directly to the commitment of the individual. If they haven't spent the time to learn it than they shouldn't be spouting off about it..
My point is that while I appreciate the diligent effort on your part to provide your theory about DIR and it's [in]applicability to California I respectfully disagree and would argue that DIR makes a diver safer, more equipped to handle California and is equally applicable in the recreational environment as it is to the technical environment..
Regards