JimsCAL: We don't have any regs on that down here - or at least none that would apply to me besides "do anything stupid and we'll bust your a$$.."
SoC: Thanks for your reply. Polishing the fuel is a great idea and something I will do, but unless it's working continually it isn't going to get all the water out of the tank, especially after it's been sitting for a week or three.. whereas opening a drain tap will.
Dabnis: Doing that now - but the water comes back out of solution if the boat isn't used for a while. Again, I'd like to take it out once and for all.
I thought as much.. but thanks for the pointer about MIG.
Any suggestions where to get the fittings?? (please don't say an auto parts store.. I've been down that road already)
Obviously I'd have to put something underneath to catch any drips, but seriously, all of the major Oil Co's use exactly what I've described on the bottom of their filter vessels which could be running anywhere between a vaccuum and over 1000kPa. Is a little unpressurised marine diesel tank a problem - really??