NavList:

>> I also get the impresion that there no regulations that say how close you have to be.  When we flew there were national and international regs that governed the accuracity of your fix and procedures to follow if you found you were off course.  I am sure there are similar rules in a channel or port but not on the open ocean.<<

John,

I think part of what you may be looking for does not exist, namely regulations governing the required precision of fixes on the high seas.  There ARE some comprehensive international regulations in place, but they focus primarily on the prevention of collisions between vessels. 

     There are 46 rules, and the prudent mariner will
      internalize most of them (plus Annex IV) before 
      sailing at night or straying very far offshore.  
      See http://laws-lois.justice.gc.ca/eng/regulations/C.R.C.,_c._1416/page-4.html 
      for a list of these standardized regs plus a few 
      local tweaks introduced by the Canadian gov't
      for local waters.

As for the accuracy of fixes, the prudent mariner recognizes that there is a continuum of what is possible under different conditions.  But he wants his navigation to be as accurate as possible at all times.  He does NOT want to wake up to the sound of crashing surf on rocks when he still thought he was 50 miles offshore.  If the prudent mariner judges that conditions are poor, and that the accuracy of his current fix is degraded, he will take steps to compensate for his imperfect knowledge.

For instance, if his electronic navigation is down because he got a bad batch of diesel (which means that several days ago he lost the ability to recharge his battery banks), and there was a communication breakdown with his wife as to who was responsible to check the handheld GPS batteries for corrosion, he needs to have a sense of just how accurate his celestial fixes are likely to be.  In reading navigational texts, you will run into the phrase "circle of uncertainty" (or even "ellipse of uncertainty").  Having a sense of how BAD your fix might be tells you how far you need to aim to the south (or to the north) of the entrance to the Strait of Juan de Fuca rather than setting a direct course to it.  This way, you know whether to turn north or south when you arrive at a shoreline you don't recognize.

If you think your circle of uncertainty is really small, then you might choose to aim directly at the mouth of the strait and expect to hit it on the first try.

Bob