On Fri, 11 Sep 1998 16:15:56 +1000 (EST), David Reinhard wrote:

>Hi,
>        I have been a lurker on this list for a few months, and have found
>it (usually) a good source of information. I have a couple of questions that
>would be best answered by the WKPP (but all opinions welcome), if someone
>could oblige me. In particular I found the reply about why stage bottles
>should be on the left of particular interest, so I am hoping that I may get
>a reply of similar quality. Forgive my ignorance on these matters but I am
>just trying to learn to dive safer.


Stages are carried exclusively on the left so that they do not interfere with
donation of the long 
hose, which is run off of the right post.  The light cannister is worn on the
right hip, and stages 
on the right side could potentially damage the canister.  As well, the
discharge thrust from a 
scooter (operated with right hand) will be on the right side, and so stages are
on the left to 
avoid interference with the flow.


>1.  I have seen 80/20 nitrox described as stroke mix, and I am not quite
>sure why. Is there a particular problem with 80/20? How about other mixes
>such as 50/50, 60/40, 70/30 or even 100%? I have been using 50/50 since I
>can come onto it at around 60ft and I feel it is important to try to reduce
>or prevent bubble formation, rather than trying to remove bubbles that have
>already formed. Is this a reasonable strategy? I have tried to search the
>archives for discussions on 80/20 but didn't turn up much of use (its
>probably there but I couldn't find it).


For a detailed answer to this question, search the archives at 
www.aquanaut.com/bin/mlist/aquanaut/techdiver  for a post with subject: "A
(Baker's) Dozen Reasons 
why we do not use 80/20"


>2. I believe that the WKPP have developed deco schedules/techniques that are
>rather out of the ordinary (but haven't been made public yet). I am
>wondering if these schedules have any relevance to the diving I do, or are
>we talking about very long and deep dives with extended deco times such as
>the WKPP do? (Most of my "deeper" diving is in the 100ft to 160ft range in
>open water, with bottom times that would usually not require more than about
>15-20 min deco). Basically I am wondering if the WKPP have developed
>anything that would make my diving safer, from the DCS point of view. (I
>appreciate that you may not wish to reveal all yet but I am curious if there
>is something in the pipeline that may benefit me in the future).


I can't answer this question authoritatively, but my guess is that there is a
lot to be learned 
from this organization.


>3.  I gather that the WKPP are using deep stops (since they are on ZPlan).
>This concept seems to make a lot of sense to me. Do the WKPP see this as an
>essential element of deco? Has this strategy been effective in reducing or
>preventing DCS cases. For the shallower dives (eg 100 - 160ft) that your
>support dives may do are you also using 'deep' stops? Has anyone empirically
>evaluated "Pyle style" stops versus "WKPP style" deep stops?


I have personally noticed the benefits of deep stops in my own diving.  Be
aware that the WKPP 
style deep stops as implemented in ZPlan assume an instantaneous ascent rate
from the first deep 
stop to the first stop given by Buhlman's algorithm.  For anything other than
an extreme bottom 
time, such as is common practice in WKPP exploration dives, the WKPP stops just
mimick the regular 
Buhlman ascent rate.  The stop times increase logarithmically as the tissues
approach saturation 
(getting close to 3 hour BT at 300 feet).  Thus the Pyle algorithm seems more
appropriate for less 
extreme dives.  If you haven't read Richard's article on deep stops, follow the
link on Jim Cobb's 
trimix page (www.cisatlantic.com/trimix/trimix.html).


>4.  Just wondering what the origin of the word 'stroke' is? (I understand
>what the term means, but were did it come from?)


I think Parker Turner coined the phrase, but someone from the WKPP can probably
answer this one.


>Thanks in advance to anyone who may be able to help me with the above
>questions,  
>
>Dave 

-Sean


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