Collision avoidance at night

[StuM]

Originally Posted by RSB333

When all three lights I see ahead,
I turn to Starboard and show my red
Green to green, Red to Red
Perfect safety, go ahead!

But if to starboard a Red should appear
It is my duty to keep clear
To act as judgement says is proper
to Port or Starboard, Back or Stop her

And if upon my Port is seen
a Steamer's starboard light of Green
I hold my course and watch to see
that Green to port keeps clear of me

Both in safety and in doubt
always keep a good lookout
In danger, with no room to turn,
Ease her, stop her, Go Astern

Which may have been relevant if you were a power vessel, but not when you are a sailing vessel "close-hauled on a port tack".


Doggerel is no substitute for knowledge of the actual Regulations and as you have clearly indicated can be dangerous.

[TeddyDiver]

Some saying about the possibility of the other vessel at constant bearing bearing away which is basicly impossible at night (if you didn't see their compass lights or eye balls earlier), so it's allways a vessel on a collision course..

[GeneM]

You are right to question the answer, because it doesn't agree with the rule. For license exams, you can submit a protest to the question when you submit your test.

If you are close hauled with the wind on the port side, you are almost going into the wind, a few points off to stbd. The green light you see has to be a sailboat under sail on your port side, because of no mast head light or towing vessel near.

So, the green light means the boat is pionted across your bow. On steady bearing means that the other boat is to windward.

Therefore, both boats have the wind on the same side. The rule says the boat to windward gives way (International rules). So, you should stand-on, maintain course and speed.

I taught the rules at a Maritime Academy and found issues with questions often. Just get the right thing in your head and plan to protest if necessary.

The question writer was probably trying to get at the part where the determination is uncertain and failed.

Practically, boats don't follow the rules so, just make sure you don't hit anything.

For your question, it's easy to see that the other boat is on the port tack and would show green. You, also on the port tack, with the sail off to stbd gives you a clear view of the green.

[Kian]

Originally Posted by GeneM

Therefore, both boats have the wind on the same side. The rule says the boat to windward gives way (International rules). So, you should stand-on, maintain course and speed.

Please have a look through the thread, there are a number of diagrams that show that the situation as described in the answer, with the other boat on a starboard tack, is possible if the other boat is somewhere between a run and a broad reach. Which would make you the give way vessel.

[StuM]

Originally Posted by Kian

Please have a look through the thread, there are a number of diagrams that show that the situation as described in the answer, with the other boat on a starboard tack, is possible if the other boat is somewhere between a run and a broad reach. Which would make you the give way vessel.

More to the point, as you say the other boat could be on a starboard tack. Regardless of whether it is or not, the fact that you don't know means that Rule 12 (a) (iii) applies:






if a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on the port or on the starboard side, she shall keep out of the way of the other.

[Dockhead]

Originally Posted by hamburking

The question never said the other boat was a sailboat, and it does not matter.

That the other vessel is a sailboat is indicated by the lights. As Stu said, it does matter, and very much so. If it were a sailboat on a port tack, you would be required to stand on.

Originally Posted by hamburking

It does not matter that you are on a sailboat...you must avoid collision. Considerations of point of sail, or starboard tack over port, are only for sailboat races, not COLREGS.

Stu has addressed this, but worth emphasizing -- Read Rule 12!!!

Originally Posted by hamburking

To be clear, your boat actually has the right of way, and the other boat should "starboard their wheel and show their red". But my experience is that I'm in a little sailboat and the other guy is a mega ton freighter who likely can't even see me...so I'm going to turn and get the hell out of there!

You really need to read the Rules, because none of this is correct.

1. There is no such thing as "right of way" under the Rules -- the obligation in some cases to stand on has nothing to do at all with having right of way on land.

2. There is a lot more to the order of maneuvering than starboard before port, which cannot be summed up in any poem. And in this case, the OP is give way, not stand on.

3. "Turn and get the hell out of there" is the wrong maneuver (and dangerously wrong) in some cases.

[AKA-None]

If you have a right to do something means you have the option to do or not to do. If you have an obligation then you must do. You can’t give up an obligation but you can give up a right. Does that help?

[Martkimwat]

In that situation I always recall the first couple of lines of verse to remember the rules that was in my old Sea Cadet manual, which went "Green to green, red to red, perfect safety, go ahead", it then went on,"but if to starboard red appears, it is your duty to keep clear, to starboard, port, back or stop 'er!" Since this situation does NOT apply here, [action needs to be taken, on the basis that you are on port tack, it is your duty to keep clear, bearing away will not rectify the situation as you will still be red to green, therefore the only option that will change the picture to one of harmony, is to tack and thus become Green to green. On a more obvious point, whether the boat is on port or starboard running down the wind above you, he will be showing you his starboard side and therefore a green light, you do not know which tack he may be on, therefore you must assume he is on Starboard and has right of way, if he in not, it is still the safe thing to do since the other boat, on seeing your red light to starboard will assume initially that you are the right of way boat and give way by gybing onto starboard which will change his aspect since he will need to bear away to do this and if he bears away sufficiently to pass you astern, you will then see his red light, in which case you will both be red to red and it will be safe for you to proceed. However, bear in mind that as soon as he sees you and becomes aware you are a sailing vessel (lights displayed) it is highly likely, he would want to prudently put himself on starboard tack by gybing so that he can pass behind you if needs be, but also knowing that for you to be on his starboard showing red, that you must be on port tack, this also make him the stand on vessel, hence the assumption that he is likely to be on starboard tack. When you tack it will be through a full 90 degrees to port, which although initially tuning towards him will take you well past the reciprocal heading, he will see your lights change to green and will know you have turned and will also see 'green to green' and know he is safe to proceed on course. Note that this is only the case where the other boat is close on your port bow as stated. If further out on your starboard bow (say 45º) his aspect will either increase or decrease depending on relative speeds, if it increases, you will soon see his red light, if it decreases you will soon be in the situation above and the correct action as above will then be evident. Sorry it's a bit long winded, a mobile diagram would make it immediately obvious and lot simpler to explain but I don't know how to post them.

[Lodesman]

Originally Posted by Martkimwat

bearing away will not rectify the situation as you will still be red to green, therefore the only option that will change the picture to one of harmony, is to tack and thus become Green to green.

Bearing away will correct the situation, as you will no longer be headed for the point in the ocean where you would have met. That is the bearing will decrease, the green will turn to red and all will be well.
If you choose to tack, ie. turn to port, then you better hope he is stbd other than the equally likely port tack, in which case he would likely take action by turning to stbd and into you.

[Martkimwat]

Originally Posted by Lodesman

Bearing away will correct the situation, as you will no longer be headed for the point in the ocean where you would have met. That is the bearing will decrease, the green will turn to red and all will be well.
If you choose to tack, ie. turn to port, then you better hope he is stbd other than the equally likely port tack, in which case he would likely take action by turning to stbd and into you.

If the other vessel turns to port, anything more than a couple of degrees, he will have to gybe to do so and will then be on Starboard tack, at which point he becomes the stand on vessel and whether or not he is aware of you being a sailing vessel or not. If he is, he will know you cannot be on starboard tack, if he is not, and assumes you are a power vessel, he will still be the stand on vessel. The port tack vessel hard on the wind cannot make the same assumptions if she has 'read' the other vessels lights correctly (ie it is a sailing vessel) and therefore the safest option is to tack away, which is what the yacht master scenario says is the correct answer, and I believe the collective knowledge of the RYA exam setters is most probably greater than yours or mine.

[Martkimwat]

Originally Posted by dokondr

Greats pictures, thanks! Hope you will allow me to take a liberty and use them for further clarifications:

A - is our boat, B - is another boat.

RYA Answer:
- Tack. It is a yacht which could be on either tack. You should assume it is on a starboard and take avoiding action.

1) B is on a port tack. What can go wrong:
- They (B) will see your (A) red and start bearing away and the same time you (A) are tacking to collision. As on the attached picture.
To avoid this A should tack to beam or broad reach. And still collision or no collision depends on timing and distance of maneuvers of both boats !

In your diagram, one would hope that the vessels were not as close as this before action was taken, but lets for a moment put that aside, for there to be a collision in this scenario, boat A would need to travelling nearly three times the speed of boat B. When boat A tacks, it will be a very quick change of direction whereas when boat B starts to turn, she must first gybe-onto STARBOARD- (thereby becoming the stand on vessel) and then round up, to do this in a controlled manner will mean she will have to do it relatively slowly if she is not end up on her beam ends. By the time she is on a parallel or closing bearing with boat A, boat A will be further ahead, and being the faster boat, will be drawing away, all this assuming that boat B, taking longer to manoeuvre, does not see boat A tack much more quickly even if both boats were travelling at the same speed. Your diagram does not equate to the real world. for there to be a risk of collision with two boats of similar speed in your scenario they would not have each other close on the bow of each other but more like 45º off their respective bows, the same dynamics would apply, boat A would tack much quicker than boat B could gybe and then round up, and therefore boat A would be well ahead of boat B by the time it completed its manoeuvre. Going back to your scenario showing the boats as close as they are, both watch keepers would have to be asleep to get into that level of proximity before action was taken.

[Lodesman]

Originally Posted by Martkimwat

If the other vessel turns to port, anything more than a couple of degrees, he will have to gybe to do so and will then be on Starboard tack,

I think you should go back and look a some of the diagrams - they explain the possibilities. The other vessel is either on a port tack, beam or broad reach and upwind so clearly the give way and his most likely course of action is to bear off turning to stbd; or on a stbd tack on a run or very broad reach - he would likely hold course, but if he wanted to do a 17(a)ii manoeuvre, doubtful he'd want to gybe, so again a turn to stbd.

at which point he becomes the stand on vessel and whether or not he is aware of you being a sailing vessel or not.

You don't manoeuvre and "become the stand on vessel"

If he is, he will know you cannot be on starboard tack, if he is not, and assumes you are a power vessel, he will still be the stand on vessel. The port tack vessel hard on the wind cannot make the same assumptions if she has 'read' the other vessels lights correctly (ie it is a sailing vessel) and therefore the safest option is to tack away, which is what the yacht master scenario says is the correct answer, and I believe the collective knowledge of the RYA exam setters is most probably greater than yours or mine.

Let's get this straight - any competent authority (such as RYA) does not craft questions where you assume the other vessel might possibly have a light out, or a moron at the helm. They specifically put you in a sailing vessel, which will be properly lit, and give the proper lights for the vessel you are encountering - a stbd running light only - so a sailing vessel.

Then there's your terminology - "tack away" what is that? You tack into the wind, not "away" from it. So a tack, in this case a turn to port would take you into the likely path of the other boat if he was to take action. Turning away from the wind, or falling off aka turning to stbd would take you away from the collision point if the other vessel stands on, and will not interfere with his manoeuvre if he doesn't stand on. And if he does the stupid thing and turns to port, thus maintaining a steady bearing with you, it will put the collision point further out, giving you more time to assess and deal with the situation.

[Martkimwat]

Originally Posted by Lodesman

Let's get this straight - any competent authority (such as RYA) does not craft questions where you assume the other vessel might possibly have a light out, or a moron at the helm. They specifically put you in a sailing vessel, which will be properly lit, and give the proper lights for the vessel you are encountering - a stbd running light only - so a sailing vessel.

Then there's your terminology - "tack away" what is that? You tack into the wind, not "away" from it. So a tack, in this case a turn to port would take you into the likely path of the other boat if he was to take action. Turning away from the wind, or falling off aka turning to stbd would take you away from the collision point if the other vessel stands on, and will not interfere with his manoeuvre if he doesn't stand on. And if he does the stupid thing and turns to port, thus maintaining a steady bearing with you, it will put the collision point further out, giving you more time to assess and deal with the situation.

My phrase to Tack away meant any from the situation, I am quite aware what a tack is and for you to pick up on that shows you are being obtuse and looking for an argument, rather than trying to understand the situation being explained, which you patently don't since it is not possible boat B to turn towards you without either already being on starboard tack or for her to Gybe on to Starboard tack, If you don't believe me, get yourself a piece of paper and a pencil and draw the scenario out, you will see it is quite impossible without being on starboard tack long before the vessel is anywhere near turning into you unless that vessel has found a way of sailing backwards towards you. If you cannot see what is plain to see, there is no point in trying to explain it to you further, I just hope I don't come across you sailing in the Solent or the South of England generally, or anywhere for that matter.

[dokondr]

Originally Posted by Martkimwat

In your diagram, one would hope that the vessels were not as close as this before action was taken, but lets for a moment put that aside, for there to be a collision in this scenario, boat A would need to travelling nearly three times the speed of boat B. When boat A tacks, it will be a very quick change of direction whereas when boat B starts to turn, she must first gybe-onto STARBOARD- (thereby becoming the stand on vessel) and then round up, to do this in a controlled manner will mean she will have to do it relatively slowly if she is not end up on her beam ends. By the time she is on a parallel or closing bearing with boat A, boat A will be further ahead, and being the faster boat, will be drawing away, all this assuming that boat B, taking longer to manoeuvre, does not see boat A tack much more quickly even if both boats were travelling at the same speed. Your diagram does not equate to the real world. for there to be a risk of collision with two boats of similar speed in your scenario they would not have each other close on the bow of each other but more like 45º off their respective bows, the same dynamics would apply, boat A would tack much quicker than boat B could gybe and then round up, and therefore boat A would be well ahead of boat B by the time it completed its manoeuvre. Going back to your scenario showing the boats as close as they are, both watch keepers would have to be asleep to get into that level of proximity before action was taken.

You final thought: "Going back to your scenario showing the boats as close as they are, both watch keepers would have to be asleep to get into that level of proximity before action was taken" is quite possible in real world, I think. One skipper for sure may be asleep and on autopilot.


So I would suggest the following end-to-end solution:


But first, great effort to solve this, thanks everybody! Many interesting ideas and some of them very close to the right solution :-)
So the question:
- 1.1. You are close-hauled on port tack at night. On your port bow, on a steady bearing, is a green light. What do you do?

And now the correct answer:
- Tack. Another yacht could be on either tack. You should assume it is on a starboard and take avoiding action.

There is no steaming light visible, therefore vessel is under sail. When two vessels under sail cross, the stand on vessel is the one on a starboard tack, IRPCS Rule 12(a)(i).

And the Rule about which this question is all about is 12(a)(iii):

(iii). if a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on the port or on the starboard side, she shall keep out of the way of the other.

A quick tack is the right action to take -- no time for VHF or searchlights. The Rules are clear about what to do. After we finish the tack another boat should see our green light and will rightly continue on the previous course as a stand-on vessel.

Have a look at the attached drawings: A - our boat, B - another boat. Tack is the right action but nevertheless we need be careful doing it! It may happen so another boat B will see our red light a second before we start the tack and will, according to the rules change course and we will be on the collision course. So we can still have a collision if we do it wrong. To avoid collision, after the tack A should be on a beam reach not close-hauled. Tacking to close-hauled course is dangerous!

[waterman46]

Originally Posted by dokondr

Here is a RYA question again (for everybody to be on the same page):
Q1.
1. You are close-hauled on port tack at night. On your port bow, on a steady bearing, is a green light. What do you do?


And here is my sketch (please bear with my drawing skills) showing initial situation how I understand it. Is it correct, what you think?

Not right - the question says the green light is on the PORT bow, but you show it dead ahead.

If the green light is dead ahead and not changing bearing, that boat has to be not moving at all. Or his running lights are a little angled compared to his centerline. Anyway the answer is the same, you should tack.