Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

In my experience and I have quite a bit of commercial experience, over 30 years, and through my formal education (Cal Maritime)...it really is not as complex as this thread is making it appear. I also have an unlimited radar endorsement on my license which involves some pretty complex plotting. So I know what complex is and what is unnecessary.

It's a disservice to recreational boaters to make it seem this complex. The more complex it is made, the greater the chance there is for an error. More complex also does not necessarily mean greater accuracy either. Sorry, I just disagree and I think we need to agree to disagree. :)

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Well, I think everyone is right here.

You're right that it doesn't need to be this complex IF you can make sure that every crossing is visibly safe. It means taking action far enough ahead, though, and not waiting until a mile off. EVM showed in his drawings how well it works to simply point at him, at least if you do it early enough, and if your courses are roughly perpendicular.

But the complex issues we've discussed here are not without practical application. In very busy waters -- note well though, OPEN WATER -- you will fairly often get into a situation where you don't have the luxury of just pointing at his stern until he gets past you -- because you've got other traffic you have to juggle. THEN you need to be able to figure out more exactly what's going on and how to set up the crossing, and there all this stuff becomes relevant.

You are also absolutely right if you're talking about collision avoidance in bays or harbors or lakes or any other pilotage waters -- just don't cross the fairway or wherever it is, that you can see where he's going to be, until he's past you -- easy peasy. But in open water you can get into situations where you just can't see where he's going to be or how you're going to cross with him. Then you need to drill deeper. The previous post by EVM shows really well how hard certain crossings can be to visualize. I think it's extremely useful to know what you can and can't eyeball. Many of us just don't know.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

I'm talking about all meeting, crossing and overtaking situations, anywhere.

Stick to the basics and the chances are excellent that you will be fine.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

I think these ARE the basics, aren't they?

We're not proposing a new or complicated technique, we're explaining WHY the basics are important.

I mean, specifically:

1. Take action early

2. Take positive action

3. Pass at a safe CPA.

None of that is complicated, and it's all explained in the COLREGS.

Don't you agree?

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

My postings were not to show how complex crossings are. I agree with you that they are not all that complex. And my goal is not not make them look complex but rather to avoid looking at them as simple.

The simple view is: I won'e even think about ships until they get 1 nm (i.e. close to) from me, then I'll just duck behind them. That is what I was calling seat of your pants navigation.

I hope that this thread brings home that when there are large speed differences between the boat and the ship a close crossing situation can be "fully developed" when the ship is 5 miles out. And that as recreational sailors we should be paying attention to any ship we see visually and electronically to decide if we have a close crossing situation developing.

When I run across a ship that is holding a constant bearing (in open water or with the ship in a VTS) I often just drop my speed. This of course presumes that I have detected the ship from a distance. Our relative bearings start changing (which is an obvious action) and the CPA on AIS opens up considerably.


Regards

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

I don't see how you think this is being made complex? I think many recreational boaters simply can't picture the relationship between the vessels when there actually is a risk of collision. I'm under the distinct impression that many boaters alter course and/or slow down for commercial vessels that would have passed miles away from them regardless. Certainly many things written in this thread seem to suggest a general misunderstanding of the relative motion of vessels in risk of collision situations. It doesn't do anyone a disservice to be educated on the geometry of those interactions.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

That's what I learned in my example back on page 17 or 18. It's also what I learned from this thread.

Most of us think in terms of similar speeds, like in sailboat racing, or in harbors where speeds are not all that dissimilar. Once it gets to 3:1 and 4:1, it is a completely different ballgame.

Thanks again.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Precisely!

Large commercial ships are (should be) equipped with professionally trained crew dedicated solely to navigation.

The average rec yacht at sea is equipped with a man and woman on alternate watches who are responsible for EVERYTHING.

It is unreasonable to expect that all rec yacht crew members have the training and experience in navigation of the professional seamen on commercial ships.

For those to refer to rec yachts as WAFI's is not only disrespectful, but a sign of their total ignorance of reality.

Much of this thread has been perverted by always looking at the worst case scenarios and posing that all situations should be treated as such. That is pure nonsense.

The average rec boater who is familiar with colregs and basic navigation is fine.

They do not need to learn advanced navigation techniques as used on the bridge of a 200 m commercial vessel. Of course they may do so if they desire, it is just not necessary.

Undeniable Facts:

1. Potential collision danger to John Q. increases proportionally with the size, weight, and speed of the ship on collision course.

2. It behooves commercial shipping to travel at a speed that produces acceptable profit / risk balance (which is all really tied to mullah).

3. When a risk of collision is first considered, it behooves the commercial vessel to take early action and plot a course change (even if they are stand on) so as to not have to slow down, in the event a rec yacht does something unexpected, that could require them to slow down.

4. Many of the arguments for applying more involved navigation techniques in congested waters are because commercial shipping is going 20 knots.

5. When a commercial vessel is travelling in congested waters they are required to slow down to a "safe speed".

6. If a commercial vessel is travelling at such a speed in congested waters as to make "normal" navigation practices for rec boats insufficient, one could easily argue that the commercial vessel was not travelling at "safe speed" under the conditions.

7. A rec boat is not required to have radar or AIS. A commercial vessel is. Obviously, the laws of the sea indicate that commercial vessels are held to a higher level of navigation expertise than rec boats.

8. In open waters with no congestion, keeping a good distance makes sense.

9. Never cross a bow when avoidable (most important of all).

Not a fact but a suspicion...

If the limited crew on rec boats are attempting to perform higher level navigation procedures (like those performed on the bridge of large commercial vessels) than they have the humans resources aboard capable of performing, accidents may result.

In closing, navigation really does not have to be this complicated on a recreational vessel, but, everyone is free to make it as complicated as they wish.

Except in poor visibility, just looking out the window and being aware of what is around you, and their relative bearing from you, will suffice.

Nav electronics that will provide alarms and plots may be nice to have (if one is so inclined); but are not essential.

If trying to do anything more will distract you from keeping a proper eyeball watch, DON'T DO IT.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Hi Rod, Welcome back!

In an ideal world some of what you say is true and others not so much. I've placed comments in the quoted text.

I am likely an exception in that I knew celestial navigation long before I got my Masters ticket. But the point I want to make is that recreational boaters are not exempt from knowing and following COLREGS or other navigational rules that apply to the waters on which they sail.

One of the first things I learned is that at least for the USCG in the event of a collision everyone (both vessels) are at fault. Now there is a degree to that fault but both screwed up.

It appears that you are trying to shove the responsibility for collision avoidance onto the commercial ship, "professionally trained crew" etc. This has some truth but does not absolve anyone from their responsibility.

Besides, at sea the mate on watch might be the 3rd mate assisted by an AB. The AB is actually steering the ship and keeping a lookout while the mate is futzing around with who knows what and not keeping an eye out. No slight to the AB, just showing that watch can be to lesser trained and lesser experienced watch standers.

I think it would be well to keep the discussion on crossing of a boat and a ship in open waters. Congested waters bring on new challenges and require more skill of all involved.



Again welcome back

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Please use quotations properly.

You now have many of your comments embedded with mine, and we see things quite differently.

Of course all craft are obliged to comply with ColRegs. Non argument.

Small rec boats are not required to have AIS or Radar, nor even a VHF.

To suggest the crew of small craft should have the same level of navigation training skill as commercial ships is ridiculous in my opinion.

In one breath some are claiming a number of boaters don't know Colregs at all. Yet in the next breath suggest they should spend all their time at the plotting. table. At some point, somewhere, we have to be realistic.

Incorrect! I Am not trying to shove all responsibility for collision avoidance on the commericial ship. What I am saying is that they should be held to a higher level of responsibility and the average cruiser should not be held to higher standard than the average cruiser (all complying with Colregs a given.)

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Well Rod suggested that a big ship should act as give way vessel even if they are the stand on. I can't square that suggestion with "all complying with Colregs a given". Either we all comply with the Colregs or we don't. Can't have it both ways.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Disagree. Plenty out there and a few on here who match the description perfectly.



Disagree (Who is John Q?) Big ships tend to be predictable, sail by the colregs and generally know what they're doing - generally not difficult to avoid using the colregs. Fishing boats and wafi's/motor boats can be at times completely unpredictable and either have no knowledge of the regs or not really bother with them. Easier to miss them as they are smaller.


Depends on the your definition of 'congested waters' English channel is one of the busiest places on the planet for ships - they don't slow down.




A lot of sailors prefer to use a bit more info if available, rule 7a.



Not too difficult to do more than one thing at a time :rolleyes:

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Welcome back, Rod.

I think this has been well answered by the previous posters, but just a couple of comments:

1. Certainly it is true, as we were discussing a little earlier, that most recreational sailors in most waters don't need to know that much about collision avoidance MOST of the time, and that most of us get by just fine just by keeping our eyes open and using common sense. My Dad, who only just recently swallowed the anchor after a lifetime of sailing all over the East Coast, Caribbean, Gulf of Mexico, Central America, etc., didn't even know how to use his hand bearing compass, as far as I know. And keeping your eyes open and using common sense is certainly the first and primary thing -- so so far, no disagreement.

2. But the thing is, is this -- all that is just fine, until it's not. What do you do, when you get into a situation, where you can't see what to do? Where you needed to have been understanding in a long time ago, and doing something which is not obvious to the naked eye? For some of us it might happen only once in a lifetime, but once is enough, isn't it? It's true that most of the time you can just bob along and the highly skilled professionals on the ships' bridges will just deal with it for you, but what about that day when the third mate on watch is watching porn on his laptop instead of the radar, or someone fell asleep, or they just don't see you? It happens -- it's happened to me. The first time I took my old Dad across the English Channel, he just about soiled himself -- how do you do this? How do you know where to slot in? Is that one going to run us down? (actually it was a completely different one we had the problem with). So sure -- advanced techniques are for "worst case" scenarios, which might not happen often, which means you might get along fine without them for years or decades, but what about when that "worst case" scenario does happen? Actually the "worst case" scenario may be fairly common in some waters, but that's just by the way.

3. No one ever advocated using advanced collision avoidance technique for every crossing. In fact, it has been specifically stated that most of the time, even in the English Channel, you can obviously see that a crossing is safe, or can easily make it safe, and don't need to do anything else.

4. As to what "behooves" commercial shipping to do -- I don't think it's reasonable to expect ships to slow down in congested but open water, just because there might be a recreational sailor out there who doesn't know the rules or know how to maneuver properly. Time is money for the pros, and on the contrary, if we are doing it for fun and mixing it up in their turf, it behooves US to have a decent level of competency. In open water, full sea speed is a "safe speed", even if the traffic is pretty heavy. Watch the Dover Straits on Shipfinder to see what they actually do -- and that is the reality we have to deal with. We shouldn't be out there at all if we don't have the knowledge and skill.

5. As to human resources -- yes, it is certainly harder when you're single handed, to deal with heavy traffic. What the eyeball tells you is not enough, and it's tricky to be on deck being well oriented visually and at the same time do a good job on the radar, AIS, and radio. On my boat, these jobs are assigned to different people when possible. When I'm single handed, I am more cautious when dealing with heavy traffic.

6. As to abandoning other tasks if it distracts you from visual watch -- have to disagree here. I agree that a competent visual watch is essential, but that absolutely does not exempt you from other essential tasks like proper pilotage, navigation, and collision avoidance. If you can't do it all competently, then you need to stay at home, or take on crew. All of these things are essential, and one is not a substitute for the other. You would never say "Forget the chart and depth sounder, if it distracts you from your lookout", would you? Well the same thing applies to collision avoidance -- which may require much more than just looking around with your bare eyes. Don't be a WAFI!

Cheers.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

So it appears that mariners of all types (pro and recreational) are a bit hazy on COLREGS. To combat this the ACTS project was started. Their website has a good learning tool intended to increase our understanding of COLREGS.


https://www.ecolregs.com/index.php?o...id=293&lang=en

Here is what they say:

The International Regulations for Preventing Collisions at Sea 1972 (COLREGs) are a set of rules to be followed by navigation officers to avoid collisions at sea. It is one of the most important International Conventions that all seagoing Officers must understand and be able to apply to real world situations. However, case law, as stated in the MARS and MAIB reports, indicates that many of the basic principles of the COLREGs are improperly understood and applied. It is also common practice to use the VHF Radio, although it is not prescribed in the COLREGs. C4FF's recent investigation into COLREGs found almost 50 percent of seafarers throughout the world disregard/ignore the COLREGs at sea when they are taking actions to avoid collisions. In order to create safer seas it is essential that seafarers should have a thorough understanding of the COLREGs rules and their application.

A new major and prestigious EU funded project called ACTs (Avoiding Collisions aT Sea) will address this issue by investigating the current problems in applying COLREGs. The project partners will then develop a new online course making it simpler and easier to understand COLREGs. The ACTs consortium is made up of major EU maritime education and training organisations who wish to reduce the number of collisions, and to make the seas safer.

Re: Collision Avoidance, Cones of Uncertainty, and Appropriate CPA
 

Interesting! So we now have a new classification: LAFI... License assisted f'n idiots.

The language evolves to meet new requirements!

Jim