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Old 21-09-2012, 04:29   #286
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Re: Freighters vs. sailboats

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Originally Posted by carstenb View Post
Here in Denmark we have several catamaran ferries. These babies cruise at 45+ knots. If they are 5 miles out - they will run you down in 7 minutes. so 7 minutes is all you have to figure out what to do.
I'm not sure you have seven minutes or even one minute, if a fast cat ferry is bearing down on your at 0 CPA at 45 knots, 5 miles away. I think this could only happen if they can't see you, and I think you are already dead meat if they are not avoiding you.

I also don't think it is possible without a very high quality MARPA with a very precise calculation of CPA (you will need a $3000 gyrocompass for that to work) to figure out a maneuver which will get you out of the way of a 45 knot ship 5 miles away. I mean even to know which way to turn.

So I think in that situation probably the best thing you can do is hold course and speed and shine a light on your sails and call on the VHF. And pray.

"SV Roadkill, SV Roadkill -- incoming!"
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Old 21-09-2012, 05:03   #287
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Quote:
Originally Posted by Dockhead

It depends on where you sail. I have cruised SW Florida for 15 years, at least a week or two every year, and I have never had a single ship encounter there, I mean, anything closer than probably 5 or 10 miles, in open water. Nothing which ever required me to use my HBC. Sailing coastwise a few miles out, you are not in waters much used by commercial shipping. It's so shallow there that they will be standing much further offshore than you. The only noticeable ship traffic is in and out of Tampa Bay, but that's already not open water and so different situation.

But in the Med, depending on where you are, it's quite different. In the Aegean you might encounter a ship in a way which requires you to determine whether you are on an intersecting course a couple of times on every passage, sometimes more.

In the English Channel, the busiest shipping lanes in the world, you are in unavoidable Colregs situations multiple times on every passage and you are continuously using your HBC. You may be out of sight of land, but hardly ever out of sight of at least one and often multiple ships.
Fundamentally this is where the two groups of people diverge. Many people have no experience of very busy shipping lanes ( and I don't necessarily mean TSSs ). Therese groups sail where there are occasional shipping in open water , hence the " I just keep outta his way " approach to the COLREGS.

some of us however have to sail in these very busy waters. And here the other group are based. I'm in the " rule of tonnage , but if I have to approach a ship in a crossing situation. I will abide by the COLREGS.

I also fundamentally disagree with the MCA view ( and that's all it is) on VHF usage. ch13 was setup under GMDSS for that very reason. Especially in a small difficult to see " target" like a sailing vessel I use VHF all time, including once or twice issuing a Securite call to announce my presence where I was concerned I was not seen.

Dave
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Old 21-09-2012, 05:06   #288
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Re: Freighters vs. sailboats

Dockhead - you're right. that's why the skippers of those boats say - let us avoid you , you don't have a chance.

I was between Sweden and Bornholm this past summer. I checked my horizon (reasonably clear weather), checked my course, speed, sails (say I used about 5 minutes) looked up and god damn here came the ferry at full blow.

Fortunately, I wasn't anywhere near him (or else he had altered course while still over the horizon). I don't have radar so visuals only. If the weather had been misty or poor visibility - I wouldn't have seen him until he either passed or mowed me down.
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Old 21-09-2012, 05:34   #289
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Quote:
Originally Posted by Dockhead
One P.S. --

One captain recommended the maneuver which Tony was talking about.

He said that at a certain point if you are still on a 0 CPA then you should step away from the radar set and simply aim the bow of your boat at the stern of the ship, and keep it aimed there -- noting that we will be changing course in an arc during this time.

A simple, safe manuever to pass behind another vessel without having to do any kind of calculations -- something which won't overload our pea-sized WAFI brains, I guess.

Sounds like a good tip.
I don't agree, though I agree with your long post on the intentions and wishes of commercial captains. I would make the following observations. ( not want re quote long posts)

1. For every commercial captain, that's wants us to abide my the CRs. There is the same ship that is on a collision course and either through not seeing Us or willfullly ignoring us , brings us into close proximity.

2. In my experience leaving out a few racing nutters, it is always the lack of action of the commercial vessel that causes close quarter situations to develop with sailing vessels.

3. Modern ships( and I have been on the bridge of many) are driven by radar and ARPA and increasingly by AIS. few are now " really" looking out the window anymore, very few have bow lookouts etc.

4. Hence our biggest problem is being seen, call up some ships in the open ocean and ask what they detected. I'd say ,especially in any sea way, most replied that they didn't have any idea I was there and no radar /arpa lock on me. Usually if they tune the radar or go looking for you get a " Agh there u are " response

5. The automatic assumption I make is that I am not seen and hence I will not " stand on into danger" I do not " follow the stern" As this is far too small a course change. I make big changes that leave the other ship in no doubt.

6. Crossing TSSs is tricky( I did my YM in gib , many years ago ) that has to be done with timing and I now often motor sail through TSSs to ensure consistent timing. As someone said its not the near lane that's tricky it's the far one. Crossing TSSs brings me into close quarters with big ships and sometimes I really hate that place. ( Dover straits on a stormy night is a ff-ing nightmare)

7. Large ships use VHF all the time to manage crossings , rarely they agree non COLREGS crossings. Mostly they use VHF to appraise the other ship what they are doing. I do the same.

Dave
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Old 21-09-2012, 05:41   #290
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Quote:
Originally Posted by David M
What they mean by knowing how to use the radar is to understand rapid radar plotting and using it. I have to get my radar endorsement on my unlimited license renewed once every five years and rapid radar plotting of two contacts is what is required.

One way a yacht could do this without having ARPA or MARPA or without having to learn the entire technique would be to plot the ships position on the radar screen with a grease pencil once per minute for a few minutes. You must do this on the same course if you your radar is on the heads up setting. North up and it does not matter. This gives you a relative motion line which will give you a rough idea of the ships CPA at your current course and speed. This is not the entire technique but it does let you know just how close that ship is going to get at yours and their current course and speed.

I agree that once close that there is nothing a sailboat going 5 knots can do to create a minimum CPA versus what a ship going 20 knots can do. (no solution with a rapid radar plot) The best thing you can do is to get them to acknowledge that they see you and don't keep changing course/speed which could result in confusion.
Most ships captains have no idea about the inaccuracies of small boat radar.

Be very careful about computing CPA, etc using small boat radar. The yaw error response of most small radars , from lack of processing power to poor heading sensors, means you have a " cone of error" you will find that you cannot exit the cone of error at you sailing speed before the ongoing vessel is on you.

Hence small boat radar is very difficult to rely on in the same way that large ships radar is, ie one with gyro stabilised heading. Making " fine" CPA TCA calculations from rapid plotting ( or MARPA) is a very dubious process ( see the Wakuna incident )

Small boat radar is a coarse tool, it's should be used in a very different way to a large ships radar system. Most ships captains do not understand this.

Dave (. RYA Radar Instructor )
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Old 21-09-2012, 05:49   #291
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Quote:
Originally Posted by Lodesman

If you haven't made contact with the merchant, and are on his starboard bow (with him on your port bow) would he still advocate turning toward the merchant's stern? Would anyone?

What I would do is carry on till about 3-4 miles off, then of there's no change from him I change.
I would however make a far more abrupt change to port and aim well behind his stern, then correct later. ( what's a couple of tacks to us) as I said " never stand on into danger "



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Old 21-09-2012, 06:04   #292
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Quote:
Originally Posted by Dockhead

I'm not sure you have seven minutes or even one minute, if a fast cat ferry is bearing down on your at 0 CPA at 45 knots, 5 miles away. I think this could only happen if they can't see you, and I think you are already dead meat if they are not avoiding you.

I also don't think it is possible without a very high quality MARPA with a very precise calculation of CPA (you will need a $3000 gyrocompass for that to work) to figure out a maneuver which will get you out of the way of a 45 knot ship 5 miles away. I mean even to know which way to turn.

So I think in that situation probably the best thing you can do is hold course and speed and shine a light on your sails and call on the VHF. And pray.

"SV Roadkill, SV Roadkill -- incoming!"
Yes these are the scariest situations. Where you detect a fast vessel at a relatively close distance , here all you can you is apply the COLREGS. , use the VHF, shine lights , AiS transponders, prayer mats and the sacrifice virgins ( getting very difficult now). Turning around etc isn't on, at best you could align yourself with his direction of travel. I always hope that I'd just loose the mast and appear out from under the cat!!! .

In reality the COLREGS are completely inadequate to handle situations where there is a " huge" speed difference. They only work where the fast craft CAN SEE YOU., because you are the rabbit in their headlights. If they dont see you you can easily be run over. No COLREGS here can help what you really need is a capability of 20 knots.

I've been on the bridge of one of the big Stenaline cats. jeepers the ground these guys are covering. It's all driven like a computer game, usually they are driven by two full captains ( ie more like a plane ) in one case both had turned and were talking to me. It struck me we could have run down about a dozen sailboats in that time.

In reality if you are in these guys operating area , you need AIS absolutely so. The key is to have early detection. Then I call them on the VHF , ensure they know I'm there and then I apply the COLREGS.

Outside of that what I try to do is avoid their route. Usually they like straight lines

The same situation occurs in the Messina straights. I had 6 fast ferries bearing down on me. They come out , sharp turn to join the TSS , turn into it and then execute a sharp turn to exit the TSS. You have to guesstimate all this and beleive you me these guys don't give way for WAFIs , COLREGS tends to go out the window. The key is to get out of their route, fast other then that get into the TSS and hope they don't turn into you.

Dave
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Old 21-09-2012, 06:17   #293
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Re: Freighters vs. sailboats

Dave,

If you think its scary when you can see them........

Try when it is poor visibility (no not fog - just reduced visibility) I mean BOOOM and they are right on top of you. I have to say though that here in DK they are fully aware of all the pleasure boats and constantly on the lookout.

Matter fact - I can't remember at single instance of them running anybody down
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Old 21-09-2012, 06:32   #294
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Re: Freighters vs. sailboats

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You must be very proud of yourself for knowing the difference between imply and infer.
When some people are so vociferous and so wrong, they might accept that they can still learn something and show a little humility.

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Originally Posted by Rakuflames View Post

What you keep missing is that you're reading in between the lines and assuming that what you thus imagine is what someone has actually said. You don't get the LIMITS of what you see as implying and the activity of inferring, so it doesn't matter if you can recite the definitions or not.
Do you know what irony is?
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Old 21-09-2012, 06:49   #295
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Re: Freighters vs. sailboats

:dead horsebeat:

Are you guys about done arguing semantics and the difference between inference and implication?
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Old 21-09-2012, 07:05   #296
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Re: Freighters vs. sailboats

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Originally Posted by carstenb View Post
... Because unless you are endowed with super eyesight, you will not be able to see a ships day signals for constrained in ability to maneuver or ship not under command. The ship will have to get fairly close before you can determine this.

Since you are unable to determine the status of the approaching ship(and you have determined that there might be a collision), prudence, and good seamanship require you to alter course to avoid

... Assuming, a freighter is coming at you at 20+ knots and is only 1 or 2 miles away - you can rest assured that they in no way will be able to avoid you. Therefore, a collision is imminent and the colregs require you to take actions to avoid.

...(we're talking about them being say 5 miles out - they can only "see" you on their radar)....
A couple points I disagree with.
1. With binoculars you can see day shapes easily at 3-4 miles. You can predict CBD traffic based on geography; NUC vessels are uncommon and RAM vessels are often announced by NTMs or Securite calls. There is little need to treat all power-driven vessels as privileged.

2. A freighter at 1-2 miles can still avoid you. If they haven't already taken action (assuming open ocean) then you should be thinking they haven't seen you and take the appropriate action yourself. Turning and stopping performance guidelines were posted earlier.

3. You are not invisible. In clear visibility you will be readily visible to the horizon - remember with the height of their bridges, their distance to horizon can be 9 miles or more. Obviously colour of your vessel/sails can have an effect on your being seen; and you'll usually be more visible with your sails up. If there is haze, fog, rain, smoke, whitecaps, whatever then you'll be lessvisible. Your best way to gauge how visible you are, is to note the range at which you can make out the merchant vessel. If he only comes into view at 5 miles, then you should assume that you will only be visible on radar to him.
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Old 21-09-2012, 07:13   #297
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Re: Freighters vs. sailboats

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Originally Posted by goboatingnow View Post
What I would do is carry on till about 3-4 miles off, then of there's no change from him I change.
I would however make a far more abrupt change to port and aim well behind his stern, then correct later. ( what's a couple of tacks to us) as I said " never stand on into danger "



Dave
Notwithstanding that rule 17.c applies to power-driven vessels, do you not consider it imprudent to alter to port? If you're sailing at 5 kts and the freighter is steaming at 25 kts, you'll be fine on his stbd bow, yet he will be just ahead of your port beam.

Quote:
17(c)
A power-driven vessel which takes action in a crossing situation in accordance with subparagraph (a)(ii) of this Rule to avoid collision with another power-driven vessel shall, if the circumstances of the case admit, not alter course to port for a vessel on her own port side.
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Old 21-09-2012, 07:17   #298
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Re: Freighters vs. sailboats

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Are you guys about done arguing semantics and the difference between inference and implication?
Do pay attention. Maybe you can't tell from her post, but she conceded that particular argument.
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Old 21-09-2012, 07:44   #299
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Re: Freighters vs. sailboats

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The people who think that avoiding collisions is as simple as running away from one encounter don't always consider that such an action might mean turning into others, perhaps worse, dangers, or causing dangerous situations by one's unpredictable and unexpected course changes. Prudence, humility, predictability, visibility, and knowledge of the rules are all needed.

Do you *really* think that people who are avoiding one vessel would do it in a way that made them run into another? I just don't understand that kind of thinking. Turning away from a collision is prudent, humble, predictable, visible and follows the rules of the road.
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Old 21-09-2012, 07:46   #300
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Re: Freighters vs. sailboats

"A point or two that seem to have been forgotten

In open sea, it makes sense to clearly alter course to get out of the way of larger ships. "


???

It's been said over and over and over and over and ...
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