Ellen MacArthur wrote:

How come? You got it wrong too when in your other post you
talked about one of the boats being overtaken.

I see you people need a hint: Subtract the angles. Does the
result fit the definition of overtake?

A vessel shall be deemed to be overtaking when coming up with another vessel
from a direction more than 22.5 degrees abaft her beam, ...

You have described the course that each vessel is on, the subtraction of one
from the other being 28 degrees - but this doesn't pertain to the direction
from the beam of the vessel being overtaken. You didn't define their
positions, only their courses, and stated that their courses look like they
will converge (which, for colreg purposes, is close enough to be considered
a potential collision situation).

So, we have a boat on 208deg, and another (catching up on the first) on
180deg, with a convergence point ahead if they maintain these courses.
Whether the catching boat is 22.5deg abaft of the other boat's beam is
unknown - they could be on a collision course, or not, depending on their
positions. See...

http://sports.webshots.com/photo/826...48327613VRqQxV

In the left-hand diagram, the green boat is overtaking the red one, but it
isn't in the right-hand diagram because it's ahead of the green one's
imaginary line representing 22.5deg abaft her beam. Until you define their
positions, it cannot be said for sure that the situation is an overtaking
one.

In lieu of that, I would say that the windward boat has to keep clear.


--
Capt Scumbalino

On Wed, 13 Sep 2006 00:00:02 +0100, "Capt. Scumbalino"
wrote:

Ellen MacArthur wrote:

How come? You got it wrong too when in your other post you
talked about one of the boats being overtaken.

I see you people need a hint: Subtract the angles. Does the
result fit the definition of overtake?

A vessel shall be deemed to be overtaking when coming up with another vessel
from a direction more than 22.5 degrees abaft her beam, ...

You have described the course that each vessel is on, the subtraction of one
from the other being 28 degrees - but this doesn't pertain to the direction
from the beam of the vessel being overtaken. You didn't define their
positions, only their courses, and stated that their courses look like they
will converge (which, for colreg purposes, is close enough to be considered
a potential collision situation).

"The one catching up is going on a course of 180 degrees" If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.

So, we have a boat on 208deg, and another (catching up on the first) on
180deg, with a convergence point ahead if they maintain these courses.
Whether the catching boat is 22.5deg abaft of the other boat's beam is
unknown - they could be on a collision course, or not, depending on their
positions. See...

http://sports.webshots.com/photo/826...48327613VRqQxV

In the left-hand diagram, the green boat is overtaking the red one, but it
isn't in the right-hand diagram because it's ahead of the green one's
imaginary line representing 22.5deg abaft her beam. Until you define their
positions, it cannot be said for sure that the situation is an overtaking
one.

In lieu of that, I would say that the windward boat has to keep clear.

On Wed, 13 Sep 2006 00:12:02 +0100, Goofball_star_dot_etal
wrote:

On Wed, 13 Sep 2006 00:00:02 +0100, "Capt. Scumbalino"
wrote:

Ellen MacArthur wrote:

How come? You got it wrong too when in your other post you
talked about one of the boats being overtaken.

I see you people need a hint: Subtract the angles. Does the
result fit the definition of overtake?

A vessel shall be deemed to be overtaking when coming up with another vessel
from a direction more than 22.5 degrees abaft her beam, ...

You have described the course that each vessel is on, the subtraction of one
from the other being 28 degrees - but this doesn't pertain to the direction
from the beam of the vessel being overtaken. You didn't define their
positions, only their courses, and stated that their courses look like they
will converge (which, for colreg purposes, is close enough to be considered
a potential collision situation).

"The one catching up is going on a course of 180 degrees" If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.

Oops! 90+ 14...


So, we have a boat on 208deg, and another (catching up on the first) on
180deg, with a convergence point ahead if they maintain these courses.
Whether the catching boat is 22.5deg abaft of the other boat's beam is
unknown - they could be on a collision course, or not, depending on their
positions. See...

http://sports.webshots.com/photo/826...48327613VRqQxV

In the left-hand diagram, the green boat is overtaking the red one, but it
isn't in the right-hand diagram because it's ahead of the green one's
imaginary line representing 22.5deg abaft her beam. Until you define their
positions, it cannot be said for sure that the situation is an overtaking
one.

In lieu of that, I would say that the windward boat has to keep clear.

Goofball_star_dot_etal wrote:

"The one catching up is going on a course of 180 degrees" If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.

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.


--
Capt Scumbalino

Capt. Scumbalino wrote:
Goofball_star_dot_etal wrote:

"The one catching up is going on a course of 180 degrees" If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.

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.


Ha....speed....said it was a variable....

.... 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.


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.

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!

Fresh Breezes- Doug King

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.

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.


Jeff wrote:
"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"?

No, *I* wouldn't but then I'm not the one trying to write a
tricky question.


Remember, if it was ever more than 22.5 abaft the beam it's overtaking.
And, if there's any doubt, overtaking is assumed.


Right, that's why the running lights are arranged the way
they are. Although I never heard a skipper say to a crew
"Take a transit off the running light blinder & tell me if
that other boat bears more or less that 22.5 degrees aft of
our beam." The phrase just doesn't have that nautical flair
to it.



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.

So what's the big deal? The boat "catching up" has to dodge
the other one, which is pretty much what everybody has said.
If "Ellen M" has any point-awarding authority then she
should give everybody some.

DSK

DSK wrote:
....



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.

So what's the big deal? The boat "catching up" has to dodge the other
one, which is pretty much what everybody has said. If "Ellen M" has any
point-awarding authority then she should give everybody some.

Ellen mis-understands the rule and claims the heading imply this is
not overtaking. She get -100 points for not understanding her own quiz.

On Wed, 13 Sep 2006 00:49:02 +0100, "Capt. Scumbalino"
wrote:

Goofball_star_dot_etal wrote:

"The one catching up is going on a course of 180 degrees" If they are
to converge "the direction from the beam of the vessel being
overtaken" must be less than 28 degrees.

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.

Yes, I had a bad brain fart.
It was specified in the question that the situation to be considered
was that they would collide if both boats maintained course and speed.
("if it looks like they're going to hit each other"). Drawing vectors
back from the projected collision point you can say that the faster
("catching up"), 180 degree, boat has to be doing more than 1.45 times
the speed of the other, for it to be within the being overtaken
(white) sector of the 208 degree boat.