DSK wrote:
.... If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.


It's also possible that they would converge from far enough away that
there is no clear ahead or clear astern. This is defined in the racing
rules but not (IIRC) the ColRegs.

It is covered - if it's converging instead of overtaking, then for
sailboats it becomes windward/leeward or port/starboard.

There is no "clear astern" or "overlap" in the ColRegs. The
"overtaking" relationship is established if a slower boat sees a
faster 22.5 degrees or more abaft the beam. After that, the
relationship is not changed until the fast boat is past and clear.





Capt. Scumbalino wrote:
Whether or not they converge is a function of their current positions,
their
courses and their speeds. Have a look at my diagram linked to
elsewhere. If
the red boat is doing 1kt, and the green one 100kts, then the green
one will
be past the red one - will pass over the red boat's projected course -
long
before the red boat gets to the same point.

The direction from the beam has nothing to do with convergence, but is a
means of defining whether the situation is an overtaking one.


Does it make any difference which one is to windward and which one is to
leeward? I can't believe you all have chewed this over and nobody has
realized that.

"Catching up" makes it hard to have this anything other than
overtaking. If you saw a boat slightly behind your beam (say 20
degrees) and slowly converging, would you call it "catching up"?
Remember, if it was ever more than 22.5 abaft the beam it's
overtaking. And, if there's any doubt, overtaking is assumed.


As I make it out, if the two are both on starboard tack, and the faster
one (catching up) is heading 180 and the other 208, then the one first
one (catching up) will be to windward as they converge. That gives the
other boat a double right of way!

Yes, if this is converging, the slower boat is to leeward and is still
standon.