At 10:08 PM 9/9/99 -0400, David B. Widen wrote:
>Thanks Jim, that is an excellent accounting of the discussion and end points
>reach by us as a group. 

>-----Original Message-----
>From:	Jim Cobb [mailto:cobber@ci*.co*]
>Sent:	Thursday, September 09, 1999 1:19 PM
>To:	Tech Diver; kirvine@sa*.ne*
>Subject:	To FT or not to FT
>
>Hi, George. Rumor has it that I am accused of "messing with your system"
>insofar as wether to use FT or not to use FT on stage bottles. We had a
>VBTech meeting where we discussed the DIR stage bottle rigging technique.
.........
>So on the FT thing, we are not always able to dive on "stroke free"
>charters, sometimes breakinng RULE #1 is part of the game. So we agreed
>(thats "we" not "me") that it would be a good idea to add FT for 2
>reasons:
>
>1. Make it absolutely clear that the number indicates MOD and not MIX.
>2. And that we are talking FEET and not METERS (Yes, we get lots of
>European divers).
>
>I really could not come up with a reason not to use FT, hell it's just a
>couple of letters and does not effect streamlining.


Jim & David, I just went on a bottle marking journey
and here's the trip report...

After 9 months of effort, we finally got aluminium 40's 
approved by the standards authority here in Oz and the 
first shipment brought into the country. I had orders 
for the entire shipment before it landed.

Anyway, this weekend I had a tank painting session and, 
on the way, made some decisions just like yours - and 
for the same reasons.

On the 50/50 bottle I put '21' (we're metric). Then I 
figured that 99% of the divers round here would read 
that as 21 percent (air) not 21 metres. So to let them 
know that the cylinder didn't contain air I added the 
letter 'm' for metres next to the '21'.

Then I put the word 'oxygen' on the 02 cylinder. And
next to it the number '6' in the same size type. Oh 
Mama it looked tres tasty. 

Then I stood the bottles on a table at the far end of 
the garage, turned off the light and looked at them.

Fucking pathetic! Not only did I now have one bottle 
marked primarily as to depth and the other as to 
contents (some system, huh?), the letter 'm' after the 
'21' added confusion, not clarity. It prevented instant 
'flash-card' recognition of the number and created a 
long typographic profile which was hard to decipher at 
distance.

In a zen-like moment of enlightenment I realised then 
that the ONLY information you're looking for and need 
underwater is depth. Just the numbers, nothing else. 

What I'd done by trying to indicate that the '21' 
didn't contain air, and by making the word 'oxygen' 
relatively too big was to pervert the DIR depth marking 
system. 

Depth is a below the water problem. It's taken care of 
by the big numbers on the bottle for use and guidance 
when diving.

Contents is an above the water problem, taken care of by 
the contents marking on the shoulder of the cylinder for 
use and guidance when filling & testing.

And I was trying to use the DIR *DEPTH* marking system 
to indicate *CONTENTS*.

So I cleaned off the 'm' and voila - the '21' jumped 
out like dog's balls. Next, I repainted the '6' on the 
02 cylinder in the same big-size numerals as the '21' 
so now the depth screams out on that cylinder too - and 
having the numerals same-size on all cylinders adds the 
consistency that makes the system work.

The word 'oxygen' in smaller type on the 02 bottle then 
becomes a discriminator - a distinctive mark at a 
distance, and an aid to orientation up closer. The 
lights-out test confirms this. More importantly, it 
also serves the purpose of marking the cylinder for 
emergency use on the surface.

Once again, the DIR system is right. I keep doing this -
making 'improvements' to the system, only to discover 
that it's already an 'improved' system. 

At least now I only DIW in the privacy of my own garage.

rgrds  billyw


--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]