Challenge: Collision Avoidance!

[Ex-Calif]

This is a good one Pelagic. I took the liberty of trying to plot the positions. My artwork is not near as fancy as Pelagic's though.

Naturally in a real case you wouldn't have all this time and I would have probably proceeded as I described - maybe not the right answer.

I plotted current positions and positions in 12 minutes assuming no change by any boats - this gives an idea of the problems the other skippers are trying to solve and helps predict what they might do.

We don't have a bearing to P1 so I assumed that he might be between 30 and 45 degrees of the port bow. Then I predicted the collision point.

Note that the angles of P1 create some doubt.

OT1 seems to have an easy choice. In 12 minutes she will be still be about .8nm from the danger zone at current course and speed. She should simply slow to 5 knots and be well out of the fray.

OT2 has the biggest problem - she is in the danger zone at many speeds. She is already turning 15 knots and would likely not want to go faster. In the worst case angle she will want to simply slow to 5kts. In the best case angle she wants to adjust to starboard and holds speed.

OS - Our safest course of action near term is to simply stand on the brakes and see what happens. In the worst case angle P1 passes a mile ahead. In the best case angle she passes a mile ahead.

Stepping on the gas to 14 kts gives us an arc ahead of P1 but it's tight. Adjusting to starboard helps but OT2 may make that problematic.

If P1s course or speed changes we have to rethink the plan.

I am assuming that the radar is working perfectly and we would have a bearing to P1 making this angle thing moot.

[Morgan Paul]

Originally Posted by Pelagic

Can you be more specific in what direction you would take?

No. It would be best to wait and see. By slowing down you do two things you get the two freighters off your ass and it gives you more maneuvering room to avoid the collision. If you try to speed up you will be pushing the engine to its limit and still have two big ships close behind.

[Wanderlust]

If you increase speed and continue in the same direction you are slightly reducing TCPA for P1 (now approaching at 36 knots rather than 32), and substantially extending the time you have limited manouverability (OT-2 will now be creeping closer at 1 knot relative to you).

However, while P1's movements may be unpredictable, you can be sure those on the bridges of of the freighters behind you will not be going off for a smoko break in the near future. They would also be assessing the situation, and will be unlikely to maintain course and speed. They probably have less interest in the paint scratches a Swan would cause than the big ouch from a fast moving tanker. So I would get out of their way.

Based on the stated speed and times, OT-1 is about 250 metres behind and OT-2 is 500 metres. They are also separated by 250 metres and you are roughly in the middle. You have enough time and room to turn around. I would immediatley make the 180 degree turn (to starbord as there is more time and room) and increase speed to maximum. You will be past OT-1's bow in 30 seconds followed quickly by OT-2. They will thank you for getting out of the way and giving them one less thing to think about. The chance of getting sandwiched between them is very low, because they will be working to maintain separation distance between each other anyway.

You can then sit back and watch the drama unfold.

[Morgan Paul]

You have enough time and room to turn around. I would immediatley make the 180 degree turn (to starbord as there is more time and room) and increase speed to maximum. You will be past OT-1's bow in 30 seconds followed quickly by OT-2. They will thank you for getting out of the way and giving them one less thing to think about. The chance of getting sandwiched between them is very low, because they will be working to maintain separation distance between each other anyway.

The problem with that is it might confuse the two ships behind you. You can always do a 180 after those guys pass.

[Eleven]

Advise OT1 and OT2 that I intend to reduce speed to 3kts and HOLD COURSE.
Turn on any additional lights that may help following traffic to maintain visual contact.

I'd rather be behind the following vessels with freedom to manouvre than in front with potential of being hit from behind. I both slow significantly the risk of being hit by them reduces, P1 remains the major threat, observe heading changes, they have no rudder, and avoid crossing their likely path.

[Lodesman]

Originally Posted by Karletto

it's an arpa radar, visibility doesn't matter

Except for the application of rules.

[Lodesman]

There's more than one way to skin a cat, but here's some considerations. OT2 will be 300 yards on your stbd beam in 6 minutes going 5 kts faster than you - in 6 minutes as you're being crushed by P-1, OT-2 will be 300 yards to stbd and 0.5 nm ahead of the collision - so he probably isn't as concerned about P-1 as you are. OT-1 is about 400 yards broad on your port quarter - in 7 minutes he'll be 200 yards on your port beam, so 5 minutes later he should be about 350 yards broad on your port bow -- except that's where P-1 will be, colliding with OT-1, 25 seconds before mowing you down. If you think that OT-1 is going to stand on to that collision, then slowing down or turning around may be the best answer. I personally think he'll start altering to stbd as soon as possible or he may slow down, as those are his best options. Prioritizing the contacts - P-1 is the lowest priority, even though he is closing, there is still 12 minutes where he may be able to solve his problems or alleviate the close quarters situation. OT-1 is the closest and therefore most immediate concern, followed closely by OT-2. So the priority is to not hit them, while you try to figure out what to do with P-1. imo.


Kevin

[Ex-Calif]

Well - It seems that it is all boiling down to slowing down, speeding up, holding speed, turning port or turning starboard - Go figure - LOL...

[Wotname]

Or, thinking outside the box (I just hate that phrase) - Beam me up Scotty""

[Pblais]

If P1s course or speed changes we have to rethink the plan.

It's not assured to be the same. The ship has lost steering and the engine is attempting to be manually shut down. This ship is going to do anything other than hold course and speed. The crew could be assumed to be attempting some maneuver. They are all new so they may not be able to complete it in time. Slowing the ship and perhaps a change in course would be a goal that they might get some progress on. Tripping over a swan won't change much momentum though.

You can not know what the ship will do so any information about it's current heading and speed as indicated in the scenario was just for that one point in time. Maybe the better challenge is what do you do if you are the captain of a ship that big out of control doing 22 knots headed into the fishing fleet? No early retirement plan is soon enough.

You might take the course of heading into shallow water and be sure he will run aground before you do or he catches you.

I would also have to assume OT 1 and OT 2 know that the boat is out of control too. They sure won't be steaming along with no changes either. The odd fishing boat may be in the know as well. The idea that you are the only person out there that knows is silly.

The key is when a ship is on the loose and without proper command. Everyone else is still obligated to do right. They all have to take measures to avoid a collision. No one has the right of way over P 1. If you don't take measures to avoid the collision then you were wrong as will be everyone else.

[ssullivan]

Personally, I dislike taking tests - so I'd cheat.

Considering the strait is 10-18 miles wide, I wouldn't get into the traffic lanes at all.

strait of juan de fuca map and map of the strait of juan de fuca history information page

I'd plot my course outside the shipping lanes on the Swan and keep to one side, allowing any and all commercial traffic to disregard my little boat.

I really don't allow myself into these kinds of situations in the first place.

[hellosailor]

I'm in line with Wanderlust. I'd notify VTS and do an emergency about to starboard (slightly more room there) coming to full speed west and out past the overtaking traffic, getting into clear water and not worrying about what they might try to do.

Now I've got clear water, only one oncoming "missile", and I can duck whichever way I have to in order to avoid it--and the fishing fleets. That also allows the (formerly) overtaking traffic to come up to full speed and run single file past the missile, should they choose to do so, without worrying about me.

Anything that simplifies a situation (reduces the number of players) and buys me distance and time from the problem, is probably going to make it safer. By ducking between the overtaking traffic, I'm eliminating them at a much faster speed, and simplifying the number of players.

[Pelagic]

Sean, you would be in even more trouble, fouled amongst the fishing fleet with a rogue containership bearing down upon you.

Seriously, the very well managed traffic lanes are the safest place to be in foggy conditions when there are hundred of purse seiners and gillnetters working everywhere outside them.

[Pelagic]

Originally Posted by Ex-Calif

Well - It seems that it is all boiling down to slowing down, speeding up, holding speed, turning port or turning starboard - Go figure - LOL...

Great Answers from many and as Dan said, quite a variety.

These types of scenarios we actually practised real time in ARPA radar simulators at marine college (except you were not in a Swan) and OT-1 and OT-2 were actually other students operating their virtual ships doing the same exercise in other rooms of what we thought was just navigating thru the fishing fleet to the pilot station, then it develops with all of us trying to avoid P-1.

As Paul pointed out, the rogue Super-Containership (P-1) had a habit of actually following you if you tried to finesse it by “assuming” the NUC rogue would maintain its course and speed. The simulator Instructor and DOT examiner would modify the generated target’s data to make life miserable if you tried to speed ahead of it or do a slight alteration.

The goal of that exercise was to remind Captains that even with advanced ARPA ……..“multilateral” situations can develop very quickly so you better remember the basic handling characteristics of your vessel as well as be able to quickly apply 60D=ST in your head as you wont have time to use “Trial manoeuvres” with the ARPA.

Originally Posted by Wanderlust

If you increase speed and continue in the same direction you are slightly reducing TCPA for P1 (now approaching at 36 knots rather than 32), and substantially extending the time you have limited manouverability (OT-2 will now be creeping closer at 1 knot relative to you).

However, while P1's movements may be unpredictable, you can be sure those on the bridges of of the freighters behind you will not be going off for a smoko break in the near future. They would also be assessing the situation, and will be unlikely to maintain course and speed. They probably have less interest in the paint scratches a Swan would cause than the big ouch from a fast moving tanker. So I would get out of their way.

Based on the stated speed and times, OT-1 is about 250 metres behind and OT-2 is 500 metres. They are also separated by 250 metres and you are roughly in the middle. You have enough time and room to turn around. I would immediatley make the 180 degree turn (to starbord as there is more time and room) and increase speed to maximum. You will be past OT-1's bow in 30 seconds followed quickly by OT-2. They will thank you for getting out of the way and giving them one less thing to think about. The chance of getting sandwiched between them is very low, because they will be working to maintain separation distance between each other anyway.

You can then sit back and watch the drama unfold.

Wanderlust (and Hellosailor) have explained it the best and in my opinion, I would do exactly what they suggested in a Swan informing Traffic and the other ships of my actions.

P-1 is closing at a combined speed of 32knots and will hit you in 12 minutes. If you immediately do a hard turn to starboard and come out on your reciprocal that combined speed is reduced to 12 knots and your TCPA is now 32 minutes (more if you were to increase speed as someone asked what the max was …. Wotname, I guessed at that max speed but it was a red herring anyway)

That gives P-1 more time to shut down its engine (which it miraculously does) and theoretically limits the collision impact if he chased you all over the Straits.

The Student OT-1 is ok as he should also do a hard 180 also but should wait about 1 minute for you to pass him going the other way.

Student OT-2 is screwed because he has wandered outside the traffic separation scheme in an attempt to pass both OT-1 and OS and will be punished for this.

No room to turn to Stbd because of the fishing fleet and if he just stops, continues or speeds up….it will be a messy ending!

A few holes have been punched in the simulator room after this exercise!

[Ex-Calif]

I am having a hard time reconciling the regs with the recommended actions.

The swan has 2 boats abaft the beam and should not turn in front of them.

The swan could turn to port being overtaken except the boat forward of the beam precludes this.

Regardless an emergency situation exists we only know that we are on collision with P1 and overtaken by OT1 and OT2.

An immediate 180 to starboard would not be prudent yet IMO. OT2 is only .5 miles behind and .15 to starboard beam. Arguably you could reverse an 85 foot swan in less than 1,000 feet and less than 2 minutes but now you are on a head on situation with a "likely" panicked OT2 skipper. You are also headed the wrong way in a fairway.

The radar tracks will be brightly displayed at the inquiry and I would rather be able to say - "My first course of action was to change bearing on P1 without fouling the overtaking boats. Slowing down is within the regs."

If the situation further develops you make a new decision - I would rather let OT1 pass, turn to port and cross the separation zone picking my way through the fishing boats then head back away from P1.

If OT1 reversed immediately I could also turn to port behind him Leaving OT2 room.

************************************

Rule 19

Conduct of Vessels in Restricted Visibility

(a) This rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.

(b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and condition of restricted visibility. A power driven vessel shall have her engines ready for immediate maneuver.

(c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of Section I of this Part.

(d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration in course, so far as possible the following shall be avoided:

(i) An alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken;

(ii) An alteration of course toward a vessel abeam or abaft the beam.

(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to be the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over..