All, 
   
  Because they operate in hostile environments, 
  submarines are inherently dangerous.  Accordingly, the ABS imposes strict 
  PVHO guidelines over subs designed for commercial use.  Homebuilt 
  submarines are not similarly regulated, though; in fact, there are little or 
  no controls on their design, construction, or operation. Two reasons why this 
  is so may be: (1) heretofore, there haven't been enough homebuilt submarines 
  to warrant governmental regulation; and (2) we have a good safety record: to 
  date, not one known fatality due to the implosion of a homebuilt pressure 
  hull.
   
  Now, however, with websites such as PSUBS 
  creating a forum where anyone can seek or offer advice, increasing 
  numbers of homebuilt enthusiasts are designing and building subs of their 
  own.  Resultantly, experienced subbers have cause for concern 
  because misadventures involving the inexperienced (beyond being 
  tragic) may engender restrictions on a pursuit we presently enjoy great 
  freedom in.  To avoid this, I believe we need to maintain high 
  standards of credibility within our ranks; and this implies encouraging 
  the use of caution and common sense in sub-related activities.
   
  Pros like Phil, Carsten, Captain George, and 
  others have proven their abilities, and have the 
  facilities, to design and build exceptionally capable submarines; but 
  that doesn't mean the amateur enthusiast can do the same in his own back 
  yard.  As many of us know, there's a lot more to submarines than meets 
  the eye; and as I've said before, this is one of those things where what you 
  don't know can hurt you.
   
  If you, as a homebuilt submarine enthusiast, know 
  you have a solid foundation in the design, construction, and operational 
  skills required to achieve a successful deep-diving sub, I salute you and wish 
  you all the best.  However, (IMOHO) if you 
  don't even know how to find your own waterline you probably shouldn't 
  attempt a deep-diving sub as your first project.  To me, that's like 
  a first-time novice homebuilt aircraft enthusiast setting out to build a 
  spacecraft: absurd from the standpoint that he'll probably never succeed, 
  but dangerous from the standpoint that he might kill himself (and/or someone 
  else) if he tries.
   
  I'd like to open this discussion to obtain the 
  opinions of others, for the sake of all concerned.  What do you guys 
  think might be some factors defining safe and unsafe  
  parameters for the first-time homebuilt submarine enthusiast designing and 
  building his own sub?
   
  Pat