Freighters vs. Sailboats

[jackdale]

Originally Posted by chrisjs

Jackdale:
What is the TSS?? When I looked up TSS, I found "toxic shock syndrome".

Traffic Separation Scheme (Zone). There is one between Newport and Block Island.

See Rule 10. Navigation Rules Online

[cappy208]

Originally Posted by Seaworthy Lass

If your tracks are even slightly divergent (and this may not be obvious at a distance) and you are getting a constant bearing, no collision will occur.

constant bearing is a GOOD indicator.

This is of particular significance if you have made a significant change in course and still find the other vessel is still on a constant bearing. It need not be because they made a course correction at the same time. It may just be that your tracks are diverging now. You will not collide then, despite the constant bearing.

Now, there is something for all of you to think about .

This is a 'trick question' from the RADAR observers class. There are two examples of this. The opposite course from collision, and induced errors (like my first collision example!)

[jackdale]

Originally Posted by chrisjs

Wrong TSS!!
There is no TSS between Block Island, Newport or the Narragansett.
psneeld: I agree with you about CBDR. Just that we have been in situations where it was very difficult to apply, then were very glad to have the AIS.

This one

[jackdale]

Originally Posted by cappy208

constant bearing is a GOOD indicator.

And it beats digging around the chart table for SWL's table.

If I was concerned the next thing I would do it put the radar EBL on the target or use MARPA or AIS (if available). I sail lots of OPBs, so I use what is available.

[cappy208]

Originally Posted by jackdale

Traffic Separation Scheme (Zone). There is one between Newport and Block Island.

See Rule 10. Navigation Rules Online

Oh, this is going to be a long reply.
Regulated lanes in Penobscot Me,

Portland IN/OUT

Boston

Buzzadrs Bay Regulated lanes

New York Nan to ambrose, hudson to ambrose, south to ambrose

Delaware Bay East, south east

Chesapeake Bay, East, South

Tortugas Straights,

Entire traffic lanes from Mississippi to Brownsville, all offshore traffic lanes.

(This is just what I am intimately familiar with) P.S. there are more!

[Seaworthy Lass]

Originally Posted by jackdale

And it beats digging around the chart table for SWL's table.

If I was concerned the next thing I would do it put the radar EBL on the target or use MARPA or AIS (if available). I sail lots of OPBs.

My table is not a substitute for line-of-sight or HBC methods.

For example you are NOT on collision course with a freighter. How much can you increase your speed by before it is a problem irrespective of your heading?

I am only just beginning to explore the table's possibilities.

How about instead of posting negative comments, you look at it closely and see where the table may be useful and we will all benefit .

[cappy208]

Originally Posted by Seaworthy Lass

I am only just beginning to explore the table's possibilities.

How about instead of posting negative comments, you look at it closely and see where the table may be useful and we will all benefit .

I think that is exactly the issue. The table depends upon accurate speed info. Unless you KNOW, It isn't so. Assumptions only exaggerate the issue.

[Lodesman]

This is the section from Cockcroft/Lameijer, along with the diagram they used.

The four stages in a collision situation


When two vessels in sight of each other are approaching with no
change of compass bearing, so that when there is risk of collision one
of them is required to keep out of the way by a Rule from Section 11,
there may be four stages relating to the permitted or required action
for each vessel:


1. At long range, before risk of collision exists, both vessels are
free to take any action.


2. When risk of collision first begins to apply the give-way vessel
is required to take early and substantial action to achieve a safe
passing distance and the other vessel must keep her course and
speed.


3. When it becomes apparent that the give-way vessel is not taking
appropriate action in compliance with the Rules the stand-on vessel is
required to give the whistle signal prescribed in Rule 34(d) and is
permitted to take action to avoid collision by her mancuvre alone, but a
power-driven vessel must not alter course to port to avoid another powerdriven
vessel crossing from her own port side. The give-way vessel is not
relieved of her obligation to keep out of the way.


4. When collision cannot be avoided by the give-way vessel alone
the stand-on vessel is required to take such action as will best aid to
avoid collision.


The distances at which the various stages begin to apply will vary
considerably. They will be much greater for high speed vessels
involved in a fine crossing situation. For a crossing situation involving
two power-driven vessels in the open sea it is suggested that the
outer limit of the second stage might be of the order of 5 to 8 miles
and that the outer limit for the third stage would be about 2 to 3 miles.

[Seaworthy Lass]

Originally Posted by cappy208

I think that is exactly the issue. The table depends upon accurate speed info. Unless you KNOW, It isn't so.

No it doesn't. Just take some conservative values. There is still SOME useful information to gain even using extremely conservative figures.

For example. You are doing 4 knots. If the freighter is closing in quickly take the speed of the freighter as 10 knots (it is more likely to be doing 16-18 knots so using 10 knots gives you a large margin of error). You estimate your angle off his bow is 40 degrees.
The table tells you lots:

- Firstly, there is no risk of collision.
- Secondly if you need to get out of the way of another freighter you could safely turn in towards the oncoming path of the first freighter.
- Thirdly, you could increase your speed to 6 knots and there would still be no risk of collision.

Or if you see from MARPA or AIS that his speed is 18 knots say, you know looking at the table that if your angle off his bow is 30 degrees, you could double your speed and you would still not collide (what other info gives you that?). This is just the tip of the iceberg.

It is getting late here, but I am sure if I put my thinking cap on in the morning, I would come up with other useful info we could gain if anyone is interested.

Just because a new idea is presented, there is no reason to slam it down without considering all the possibilities .

[psneeld]

Sarcastic because I know better...not only about the silly table but people in these forums that try to argue such things.

Not resistant to new ideas...as long as they replace something by being better...not more archaic and complex.

CBDR is simple, absolute and effective. Tough to beat with a table that requires thought, looking at something sometimes in an unfriendly environment and you have to GUESS at speeds and bearings (on a small boat at sea).

Just those things alone make arguing for it show the amount of real experience someone has trying to defend it.

Not saying don't use it...just learn CBDR first for the newbies...you do them a disservice if you don't push that at least.

[evm1024]

Coming in late and scanning posts....


Why were we using arc sin a few pages back and not arc tan to decide the angle off the bow in a crossing situation?

Regards

[cappy208]

Originally Posted by evm1024

Coming in late and scanning posts....


Why were we using arc sin a few pages back and not arc tan to decide the angle off the bow in a crossing situation?

Regards

Because I am mathematically challenged, and quoted the wrong thing. OR,

The topic is so easy anyone can decipher it!

[evm1024]

Originally Posted by cappy208

Because I am mathematically challenged, and quoted the wrong thing. OR,

The topic is so easy anyone can decipher it!

Nah, others used arc sin too. I was just wondering if I missed something.


Regards

[cappy208]

Originally Posted by evm1024

Nah, others used arc sin too. I was just wondering if I missed something.


Regards

I don't think it is important which it is. There is a particular topic that is being overlooked, misunderstood, bent, skewed and twisted.

The formula depends on accurate speed information. If the speed is determined, then the list is not needed.

[Wotname]

Originally Posted by Rakuflames

Any time I am at the helm. If I'm at risk of collision, no matter what course I was on before, I am no longer the stand-on vessel. I am the more maneuverable boat. I put the iron genny in gear (I turn it on any time I'm anywhere near a freighter) and I go wherever I need to go to avoid a collision. I make sure it's not some move that will force the freighter to maneuver. If that means doing a 180º the world will really keep on spinning if I'm delayed even an appalling 2 minutes. I'm not really the center of the universe, so it will not fly apart if I shift my course.

I'll do it in plenty of time, too. Two things I never play chicken with are oncoming trains and freighters/cruise ships.

I do this in time to sail away and will do that if I can just because I prefer sailing, but I have my engine in neutral as a backup because stuff happens.

My actions will be very clear and the freighter helm will know exactly what I'm doing unless he/she is a total twit, but I can't control for that. I can only accept my responsibility and do whatever is necessary to avoid a collision.

Well your method apparently works; another method that also works is to follow the colregs (all of them of course). Preventing collisions at sea is their sole purpose.
Not picking on your method, just pointing out the alternative for other readers .

Originally Posted by psneeld

Sarcastic because I know better...not only about the silly table but people in these forums that try to argue such things.

Not resistant to new ideas...as long as they replace something by being better...not more archaic and complex.

CBDR is simple, absolute and effective. Tough to beat with a table that requires thought, looking at something sometimes in an unfriendly environment and you have to GUESS at speeds and bearings (on a small boat at sea).

Just those things alone make arguing for it show the amount of real experience someone has trying to defend it.

Not saying don't use it...just learn CBDR first for the newbies...you do them a disservice if you don't push that at least.

You may not be aware that sarcasm is not the most effective tool for the more knowing to impart their superior knowledge upon the less knowing but I grant you it does sometimes make one feel snug.

Of course I have assumed that the purpose of your above post(s) was to promote good argument and further understanding about the interactions of sailboats and freighters; if there was some other intent, then please disregard my comments.