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Old 20-12-2016, 08:23   #91
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Re: Traffic Separation Zones

[QUOTE=

Do you honestly track the AIS course info on vessels 10 NM away? Enough to notice a minor course correction?[/QUOTE]

Yes I Do, But am not so concerned with course as I am with both
CPA & TCPA. I like to have total situational awareness.
If I see an AIS contact 10nm out with a CPA of 2nm and TCPA of 20 minutes I
Put it on the mental back burner. If I check it a few minutes later
and I see it's now .5nm and 9 minutes, it moves way up front
and most likely it has turned to red on the plotter.
I consider this just a part of good helmsmanship.
(These are random numbers picked just for illustration)
I also keep a hand bearing compass or a set of binocs with built in
compass close at hand. Sometimes I use one or the other just to keep
up the skill set.
Don't really understand the part of the conversation as to
"Changing course to account for tide" in or between lanes of a separation
zone. While in the English Channel we always planned where we wanted to
be ( IP Point) before entering and made calculations of the tidal effect on our crossing, using it to our advantage.
Basic passage planning.
I simply don't see how one can sail around without thinking about
"TWAT" my RYA instructors appreviation for
Think Wind And Tide
Ah, British Sense of Humor
Cheers
Neil
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Old 20-12-2016, 10:24   #92
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Re: Traffic Separation Zones

Quote:
Originally Posted by Time2Go View Post
Don't really understand the part of the conversation as to
"Changing course to account for tide" in or between lanes of a separation
zone. While in the English Channel we always planned where we wanted to
be ( IP Point) before entering and made calculations of the tidal effect on our crossing, using it to our advantage.
Basic passage planning. . . .
Yes, we Channel sailors use a technique which seems bizarre to many on here -- calculating a constant CTS which gets you to the destination without changing your heading, which is always the fastest away across.

But that's not what we were talking about. You are not allowed to steer your calculated CTS across the traffic lanes of a TSS -- while in the lanes, you are obligated to set a heading which is 90 degrees to the direction of the lane. Even if the tide sweeps you around so that your COG is oblique -- not 90 degrees. HEADING is what is required (because that gets you across the lane fastest).


Furthermore, your ideal CTS may not even get you to the TSS in the place where you need to cross. So crossing the Channel via crossing one of the TSS's is a lot more complicated, than the standard tidal vector calculated CTS way. The good news is that you are unlikely to be doing this anywhere where the Channel is very wide. The Dover Strait is the main place where you have to be clever. You can get across that pretty narrow body of water in one tide, so if you're crossing from Calais (or Dunkirk) to Dover, which is somewhat downchannel from Calais, it is usually pretty easy if you can plan to do it during the ebb.

Nevertheless -- you can't choose just any place to do it -- you need to stay out of the ferry "crosswalk" area, usually by staying upchannel of it. So the first leg of such a crossing is to get to the corner where the ferry crosswalk meets the TSS. After that, you might well need a course correction in the separation zone, which is what we were talking about.
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Old 20-12-2016, 10:28   #93
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Re: Traffic Separation Zones

Quote:
Originally Posted by Dockhead View Post
Yes, we Channel sailors use a technique which seems bizarre to many on here -- calculating a constant CTS which gets you to the destination without changing your heading, which is always the fastest away across.
But that's not what we were talking about. You are not allowed to steer your calculated CTS across the traffic lanes of a TSS -- while in the lanes, you are obligated to set a heading which is 90 degrees to the direction of the lane. Even if the tide sweeps you around so that your COG is oblique -- not 90 degrees. HEADING is what is required (because that gets you across the lane fastest).
Only someone who has crossed the Channel will know of the stomach churning anxiety when in a slow boat............
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Old 20-12-2016, 10:55   #94
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Re: Traffic Separation Zones

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Originally Posted by weavis View Post
Only someone who has crossed the Channel will know of the stomach churning anxiety when in a slow boat............
. . . which has been compared to being a gerbil trying to run across a busy autobahn . . .
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Old 20-12-2016, 11:05   #95
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Re: Traffic Separation Zones

Quote:
Originally Posted by Dockhead View Post
Yes, we Channel sailors use a technique which seems bizarre to many on here -- calculating a constant CTS which gets you to the destination without changing your heading, which is always the fastest away across.

But that's not what we were talking about. You are not allowed to steer your calculated CTS across the traffic lanes of a TSS -- while in the lanes, you are obligated to set a heading which is 90 degrees to the direction of the lane. Even if the tide sweeps you around so that your COG is oblique -- not 90 degrees. HEADING is what is required (because that gets you across the lane fastest).


Furthermore, your ideal CTS may not even get you to the TSS in the place where you need to cross. So crossing the Channel via crossing one of the TSS's is a lot more complicated, than the standard tidal vector calculated CTS way. The good news is that you are unlikely to be doing this anywhere where the Channel is very wide. The Dover Strait is the main place where you have to be clever. You can get across that pretty narrow body of water in one tide, so if you're crossing from Calais (or Dunkirk) to Dover, which is somewhat downchannel from Calais, it is usually pretty easy if you can plan to do it during the ebb.

Nevertheless -- you can't choose just any place to do it -- you need to stay out of the ferry "crosswalk" area, usually by staying upchannel of it. So the first leg of such a crossing is to get to the corner where the ferry crosswalk meets the TSS. After that, you might well need a course correction in the separation zone, which is what we were talking about.
Hi Dockhead
We are in agreement here
In an earlier post on this thread I mentioned the 90 degree rule
CTS is meaningless when crossing TSS You have to be at 90
so oncoming ships see you abeam. It's stating your intentions to cross.
What I meant was that we calculated where we wanted to start our crossing,
our "IP Point" at the edge of the TSS, then adopted a bearing 90 degrees
and used the tide to push us in the direction of our destination.
The ferry crosswalk is another variable I must have missed in this thread
Or not considered for discussion
Having spent a few summers sailing around the UK
I figured out how they built an empire, they figured out how get
the first 50 miles away.
I really enjoy cruising around those parts because it is challenging
Enjoy reading your posts
Cheers
Neil
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Old 20-12-2016, 11:33   #96
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Re: Traffic Separation Zones

Quote:
Originally Posted by Time2Go View Post
. . . Having spent a few summers sailing around the UK
I figured out how they built an empire, they figured out how get
the first 50 miles away.

I really enjoy cruising around those parts because it is challenging
. . .
Ha, ha, ha!

I think you nailed that one!
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