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Doug,
I'm
aware of very few actual "accidents" in PSUBS that we could use. There's a
couple of items in Kittredge's books that are of high value, like the time he
got blown out of his boat upon surfacing due to a very slow escape of air in the
cabin during the course of a long dive. That one led me to add an overpressure
valve to Snoopy, and it turned out to be needed on the very first dive. I
certainly appreciated George's telling that story. Of course we should
list the few accidents like that, but I'd like to propose we widen this to
"incidents". My definition of those is not just big life threatening items but
small things unlikely to be found in the likes of ABS. As an example, I'd cite
the time a prop fell off Snoopy and left me going in circles. I think the cause
was a bit of seaweed which had jammed the prop, and unwound it when I hit
reverse. Snoopy's prop nuts are now drilled and wired, and others might
want to save themselves a headache by doing that to begin with. Other examples
not likely to be in ABS but specific to subs might be how to deal with trailer
launches, towing, etc.
What
if we start small with a repository of tips like that? Ray and Jon, how would
you like to implement it?
thanks,
Alec
Doug,
Thanks for your insightful comments on how to
progress safety in our PSUB community. My terse digestion of your
comments boil down two a few key points:
- focus on the precursors to accidents, and shift
from outcome measures to process measures
- psubs community could implement this "focus on
the precursors to accidents" by establishing an area on the
website for lessons learned, common mistakes, safety observations.
- psubs community could implement a process
oriented safety focus by encouraging adherence to "a set of best safety
practices for designing, fabricating, testing, operating and maintaining
psubs" such as design guides developed by ABS, Lloyd's,
PVHO.
I for one concur and think we do a lot of this
through the existing forum. There is however, a missing piece, the
independent review.
If you actually try to get your new psub
certified as A1 by ABS, then an independent review of your design would be
conducted by an ABS inspector that would go over every aspect of the design
and then be present for certain milestones of the fabrication and
testing. This normally requires a lot of iterations on the design, were
ABS questions an issue, and designer defends design with technical
backup.
The problem is cost. Most psubbers are
willing to follow design guidelines such as ABS the best they can but do not
want to fork out the big bucks that buys the time to conduct the detail
independent review and the onsite monitoring of fabrication and testing.
The part that I see is missing then (assuming you
are not independently wealthy) is the independent safety
review. In the oil and gas industry in the US, they use something called
Process Safety Management (PSM). After the
detailed design work is done but before the design in
implemented, a team is brought together to conduct the Process Safety
Review. This team includes the designer, plus a diverse
set of outsiders such as instrumentation techs, experience
operations folks, electricians, engineers etc. They meet for a day
or so and go ever aspect of the design asking a lot of "what if" questions
focused around safety. As an example, for a process vessel design,
someone might ask, what would happen if a particular control valve stuck,
or what happens if a pressure sensor goes out or what happens if the
pressure relief valve fails. These PSM reviews almost always
generate a list of items that need fixing that the designer just did not
think of or was not aware of. A safer design is almost
always the byproduct of this kind of review.
I toyed with the idea of conducting a Process
Safety Review for my boat after I had completed all the design work and
documentation. I considered flying a few fellow psubbers in for a
weekend to do the review. In the end, I did not follow through as did
not want to pay the expense. What I did in stead was to package all of
design documentation and prints for my boat and send them to a fellow psubber
that had actually built a boat who agreed to review the work. I
then, via email, answered many, many questions over a 3 month period.
This feed back identified several weaknesses in my design that I subsequently
addressed in the final design. While this approach was not as
comprehensive as having ABS involvement and it does not result in
an ABS A1 classification of my boat, it has I think helped in improving the
overall design and safety of my boat.
How did I meet the fellow psubber, of course by
attending a Psubs convention.
Cliff
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