Rules Of The Road Question

[KWKloeber]

Paul

No question, just adding to prev post/scenarios to note that the headings of the tug/ sail are important because it determines whether it's an overtaking vs. crossing situation.  M's estimate of the tug heading was north, plus or  minus 5 degrees. That variability turns it into either a crossing vs overtaking scenario if you calculate the tug relative to M.  5 deg one way, switches the heading from 30 deg abaft of M's beamt (overtaking) to 20 deg (crossing.)

K

[britinusa]

Confused hence the request for clarification.

M: Port Tack, Broad Reach, Heading 065ºT  @ assume 6kts (Wind must be about 300º NW by W),

Tug: Under Power, Heading N± 5º (005º -355º), visible off Port Quarter, @ assume 12kts

No collision risk.

[KWKloeber]

Confused hence the request for clarification.

M: Port Tack, Broad Reach, Heading 065ºT  @ assume 6kts (Wind must be about 300º NW by W),

Tug: Under Power, Heading N± 5º (005º -355º), visible off Port Quarter, @ assume 12kts

No collision risk.

Paul you missed my mea culpa five below.  I neglected to say the Tug is to Stbd.

-k

[britinusa]

M: Port Tack, Broad Reach, Heading 065ºT  @ assume 6kts (Wind must be about 300º NW by W),

Tug: Under Power, Heading N± 5º (005º -355º), visible off Port Stbd side Quarter, @ assume 12kts

No collision risk.

Time for some more 'assumptions'

There would appear to be a risk of collision assuming that the tug's bearing from M remains constant.

The Sailboat can see the Tug's Port Light.

So it comes down to the definition of Crossing and Overtaking.

Overtaking is from within the cone of the Stern Light.
M is on 065º and Tug on either 005º or 355º

M cannot see Tugs Stern Light

Tug could see M's Stern light if it were quite a way south, otherwise it would only see M's Stbd light.

I believe that the Tug is the stand on vessel and M should take avoiding action.

That action should be to turn behind the tug, slowing down if necessary.

That would require easing the sails for a run downwind, turning to about 120º or Gybing.

Early action would ease the tension, even requiring nothing more than bearing off a few degrees.

:)

Paul

[KWKloeber]

Paul

Ok, you're on the correct path re: being stbd, and comes down to crossing vs. overtaking. 
Since overtaking is defined as approaching 22-1/2 deg abaft of beam, M's "plus or minus" estimate of T's heading can switch the scenario between overtaking vs crossing, depending.... 

Remember tho, once a vessel is overtaking, it remains overtaking until it passes the vessel ahead.

So, I'd say, if M was in doubt of T's heading, M should assume it's the give way, or at least be prepared to take action.  T should have a more precise determination of the heading than M.  This is probably prime time scenario for a VHF call.

So I agree with your reasoning.  EXCEPT gotcha (with the two added confusions of std approach and +/- heading). 

It's still a powerboat T (displaying no signals) overtaking or crossing sailboat M. 
T being 30 deg vs 20 deg abaft of M's beam is irrelevant.
T's port bow light vs, M stern light or M's stb bow light is irrelevant.
Powerboat T gives way, sailboat M stands on.

;-)

k

[britinusa]

Ken, you are correct.
Rule 18. a)

Unless the tow was displaying appropriate day shapes for Restricted Maneuverability.

:)

Paul

[Noah]

Another collision story/lesson to ponder

http://cruisingodyssey.com/2017/12/13/ships-collide-one-thought-they-would-pass-starboard-to-starboard-the-other-port-to-port/