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Old 24-04-2016, 22:13   #61
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Re: Almost run over.

I love these kinds of posts. I learn a lot.

For me, having a 1 nm CPA is impossible where I sail. There's always 10 to 20 boats within 1 nm of me. Even 20 nm off shore, there's always a ton of traffic. I strive to a 1km CPA for the large freighters. Everything else is playing dodgem.

BTW (and off topic), my hat's off the totally professional mariners on the Catalina Express. They have always given way to me when I'm under sail. Early, predicable, etc.. exactly what you'd expect from the colregs. Total pros, and tough waters to drive a large fast boat in.

OTOH, I've had to dodge driverless boats on a few occasions. It happens. I think it's tough knowing how long you should assert "stand on" until you adjust your own course. Because, if the other skipper knows their stuff, they want you to stay your course. Of course, they really never do, so I get out of the dang way. S/V is fine, it's all slow. But a M/V doing 30 kts, get out of the way.

The solution in socal is to never sail on the rhum line to Avalon from my home port. I always drop about a half mile away.
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Old 24-04-2016, 22:38   #62
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Re: Almost run over.

jeepbluetj,

"The solution in socal is to never sail on the rhumb line to Avalon from my home port. I always drop about a half mile away."

The strategy works almost everywhere people sail point to point. Going outside the mob, but inside the shipping, the boat population density drops off.

It sounded from the OP's post that the big motor yacht was on a regular chartered trip--like the story from last year-- but unless it's your own cruising grounds, you would be unlikely to expect that. And if you don't read CF, the same is true. For Colregs to have worked better for the OP, he would have had to act by turning the boat, rather than trying to make VHF contact, and at least here on CF, the advice has often been to try the VHF. I'm thinking it's good advice for some situations, but when it involves a large power boat, not a professional going about his work, is is safer for us to assume that the moment we are worried, we change our course radically enough that collision won't occur, whether it involves tacking or gybeing, that we take responsibility for working it out, like DH said, and be pro-active instead of passive.
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Old 24-04-2016, 22:42   #63
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Re: Almost run over.

Even with only a 1/2 mile before he realized the guy wasn't turning or reacting, that is probably 2 minutes he could turn and get out of the path while still calling (no reason, you can't turn the wheel while making a call).

2 minutes and the 50yd pass probably becomes 200-300yds. Annoying but little risk and that far out, the wake will tend to be much less harsh.
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Old 25-04-2016, 00:59   #64
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Re: Almost run over.

Quote:
Originally Posted by Dockhead View Post

A commercial ship, or superyacht, hull down at 10 miles should catch your attention.
On a night sail from Bonaire towards Aruba we met a crude oil tanker lying a hull with only anchor lights on. Due the haze close the horizon it wasn't visible untill we were about 1nm away . Also becouse of the slow change of bearing we didn't spot it's mast anchor light earlier from the stars. Our CPA was about 1/2nm when they did their decklights on.
They propably saw us with radar but dunno for sure. No AIS or radar on our boat. Quite unexpected encounter..

BR Teddy
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Old 25-04-2016, 01:04   #65
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Re: Almost run over.

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Originally Posted by skipmac View Post
I have to confess that my collision avoidance procedures are much closer to Jim's than Dockhead's. A lot of my sailing has been coastal Florida and the Caribbean where you might often have 8-10 big ships in a 10 mile radius, and off the FL east coast that many or more sport fishers and big yachts. I know this is minor compared to the traffic in the Channel but it was enough to keep my attention. With this much traffic there's often not room to have a minimum of 1 mile clearance between my boat and every other boat around.

For yachts, even big yachts, sailboats, sport fishermen, trawlers and such a 1/2 mile clearance in a passing or ovetaking situation always seemed like more than enough. Even for a ship less than a mile was not uncommon. In a crossing situation wider margins are preferred.

To get an idea of the limits I did the math on a worst case, potential collision scenario. A big ship is headed directly toward you and you're on a crossing course. Assume 20 kts for the ship and 150' beam, 40' sailboat and 5-6 kts. With those parameters in round numbers, it would take the sailboat 20-25 seconds to cover 150'. In that time the ship would cover about 800' or 1/8 of a mile. So one could completely cross the bow of a ship heading directly towards you when it's only 1/8 of a mile away. That same ship would take about 15 minutes to reach you from 5-6 miles away.

OF COURSE, I am not advocating anything like this, just putting this out there to give a feel for minimums needed for avoiding a collision. I still start evaluating another vessel's course as soon as I'm aware of them but unless I'm far offshore with only 1-2 vessels in sight, don't really start a close watch until 5-6 miles and have never felt pressed for time or had to make a quick maneuver to avoid anyone at the last minute.
I did not intend to imply that 1 mile should be a universal safe CPA under all conditions. In open water, one mile is typical standing orders on ships' bridges, so the process works better if we think in at least roughly the same terms. And this should be taken into consideration when deciding whether the ship has seen us or not -- if he's on a steady course and you see a CPA of 5 cables, and he's been on the same course for several miles and you're now 4 miles out, then he hasn't seen you and/or does not intend to maneuver, so you can go for it yourself.

In coastal areas or in the approaches to harbors, or inside harbors (where a lot of recreational sailing gets done), it can be very different. If he's following a channel, then you don't need to do anything except stay out of the channel until he's safely past. You don't need to even think about CPA.

It's really important for us, to not leave it until too late, though, because of the difference in speed. Some of us suffer from the misconception that we are "more maneuverable" than ships, and therefore better able to avoid collisions (why some sailors fail to stand on when required), but the opposite is actually true, except at very, very short distances. The thing is that you cannot know exactly where he will be when you cross, even if you have AIS which is working on the basis of highly accurate positions. That is because the actual crossing will be somewhat different depending on any small alterations of course and speed, especially yours, and especially if you're under sail. So in order to cross safely, you have to stay outside of the zone where he could be when you cross, which is why you need the margin of error. If you screw it up, a last minute alteration by a slow sailboat may well be incapable of resolving the crossing and sailing you out of the danger zone. The bigger the difference in speed, the more time and distance you need to open up the CPA by our maneuver, and you actually need more time and distance, than he would.


The OP was sailing between islands in the Bahamas and I assume he was in open waters. If that assumption was not correct, then the distances might be different. If you want a generalized rule, however, I would say that in most circumstances you don't want to pass closer than one mile, and certainly not passing ahead (passing behind is obviously much safer), unless you are sailing some place where you know he won't go, because it's too shallow or outside a channel he's following.

Overtaking is another situation which is different. If you're on the same course, then even a cable or two might be enough, but if he is set up to overtake you that closely, then you had better be really sure to hold your own course and not jink around. While being overtaken, you are of course obligated to hold your course, but in my opinion, being overtaken more closely than I like is one of the exceptions to the rule that you shouldn't, in general, use the radio, and I might call the ship and propose that I will alter course (usually to starboard) to give him more room.
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Old 25-04-2016, 01:08   #66
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Re: Almost run over.

Quote:
Originally Posted by TeddyDiver View Post
On a night sail from Bonaire towards Aruba we met a crude oil tanker lying a hull with only anchor lights on. Due the haze close the horizon it wasn't visible untill we were about 1nm away . Also becouse of the slow change of bearing we didn't spot it's mast anchor light earlier from the stars. Our CPA was about 1/2nm when they did their decklights on.
They propably saw us with radar but dunno for sure. No AIS or radar on our boat. Quite unexpected encounter..

BR Teddy
It has become standard practice for tankers waiting for a load to lie ahull, drifting, showing NUC signals, and with main engines shut down.

The MCA has condemned the practice, but it continues.

This can be quite dangerous for sailors; steer a wide berth.
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Old 25-04-2016, 01:16   #67
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Re: Almost run over.

Quote:
Originally Posted by valhalla360 View Post
Even with only a 1/2 mile before he realized the guy wasn't turning or reacting, that is probably 2 minutes he could turn and get out of the path while still calling (no reason, you can't turn the wheel while making a call).

2 minutes and the 50yd pass probably becomes 200-300yds. Annoying but little risk and that far out, the wake will tend to be much less harsh.
This would be correct if you had absolute knowledge about where that path is, which you have to get out of. Even with AIS you don't have that knowledge, which is why you need the margin of safety. Without AIS, you won't even know which way to turn in many cases. 1/2 mile is far too late to get a decent calculation using hand bearing compass.

So you might well get the CPA to 200-300 yards in such a case, but the risk is that you were mistaken about where he will pass, and you end up under his bows and run down, and probably dead. And by that time, you will definitely not have time for any second maneuver, if the first one didn't work. Effective collision avoidance is eliminating those risks to the extent possible.
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Old 25-04-2016, 02:32   #68
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Re: Almost run over.

Quote:
Originally Posted by Dockhead View Post
It has become standard practice for tankers waiting for a load to lie ahull, drifting, showing NUC signals, and with main engines shut down.

The MCA has condemned the practice, but it continues.

This can be quite dangerous for sailors; steer a wide berth.
No NUC lights in this case, just anchor lights. This tanker was fully loaded, maybe waiting the crude oil prices to rise.
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Old 25-04-2016, 03:17   #69
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Re: Almost run over.

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This would be correct if you had absolute knowledge about where that path is, which you have to get out of. Even with AIS you don't have that knowledge, which is why you need the margin of safety. Without AIS, you won't even know which way to turn in many cases. 1/2 mile is far too late to get a decent calculation using hand bearing compass.

So you might well get the CPA to 200-300 yards in such a case, but the risk is that you were mistaken about where he will pass, and you end up under his bows and run down, and probably dead. And by that time, you will definitely not have time for any second maneuver, if the first one didn't work. Effective collision avoidance is eliminating those risks to the extent possible.
Assuming the other boat is holding course, I can get a rough idea of a mega yachts heading at 1/2 mile. Turn 90 degrees away from where I think he will be and keep watch. If you are wrong, your heightened awareness should let you know fairly quickly with the ability to react and choose another course accordingly.

While there could be some strange situation where it doesn't work. 99% of the time, if the OP had turned at the 1/2 mile range and then made the call, he would be far beyond the 50m closest point if no one answers the call and reacts.

(again, assume open water with no obvious channel that would dictate the mega yacht would turn)

We regularly have high speed boats pass us and once you know they are there 1/2 mile out, the passing on open water should not be an issue. Usually, we observe them as they approach and angle away from their heading (no radar or AIS). Almost never bother to call them as we can observe their heading. Unless there is a restricted channel, it's never more than a nuisance from the wake being a bit larger than we care for...but again, if I know 1/2 mile out, I will be paying attention to the wake and yell to anyone below to hang on there is a wake.
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Old 25-04-2016, 06:13   #70
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Re: Almost run over.

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Assuming the other boat is holding course, I can get a rough idea of a mega yachts heading at 1/2 mile. Turn 90 degrees away from where I think he will be and keep watch. If you are wrong, your heightened awareness should let you know fairly quickly with the ability to react and choose another course accordingly.

While there could be some strange situation where it doesn't work. 99% of the time, if the OP had turned at the 1/2 mile range and then made the call, he would be far beyond the 50m closest point if no one answers the call and reacts.

(again, assume open water with no obvious channel that would dictate the mega yacht would turn)

We regularly have high speed boats pass us and once you know they are there 1/2 mile out, the passing on open water should not be an issue. Usually, we observe them as they approach and angle away from their heading (no radar or AIS). Almost never bother to call them as we can observe their heading. Unless there is a restricted channel, it's never more than a nuisance from the wake being a bit larger than we care for...but again, if I know 1/2 mile out, I will be paying attention to the wake and yell to anyone below to hang on there is a wake.
Well, I certainly agree with you that the OP, having failed to spot the superyacht earlier, should have immediately changed course when he did spot him.

But I think you are optimistic thinking that it will be obvious which way to turn. In a close pass you can't tell from eyeballs. If it's obvious which way to turn -- if you can detect a changing bearing with your bare eyes -- then there will be some significant CPA. If it looks like a collision course, at half a mile off, then CPA might be zero, might be a cable this way, or a cable that way, and you can't see the difference. Even AIS might not be able to determine it that accurately. So turning is a crapshoot. Say roughly a one in three chance that your turn will make it worse and put you under his bows.

That's what you aim to avoid by doing collision avoidance right, and at the proper distance away.
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Old 25-04-2016, 07:03   #71
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Re: Almost run over.

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It might be a bit of a stretch referring to Yacht crews as professional mariners. Some are, a lot aren't.

Of course, the overtaking Yacht should have given you more room, but allowing yourself only a 50 foot CPA when you were aware a risk of collision existed might not have been your most prudent course of action.

A couple clicks to starboard on your autopilot a few miles out probably wouldn't have ruined your day.

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True. There is a big difference between a paid crew and a professional crew.
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Old 25-04-2016, 07:06   #72
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Re: Almost run over.

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Well, I certainly agree with you that the OP, having failed to spot the superyacht earlier, should have immediately changed course when he did spot him.

But I think you are optimistic thinking that it will be obvious which way to turn. In a close pass you can't tell from eyeballs. If it's obvious which way to turn -- if you can detect a changing bearing with your bare eyes -- then there will be some significant CPA. If it looks like a collision course, at half a mile off, then CPA might be zero, might be a cable this way, or a cable that way, and you can't see the difference. Even AIS might not be able to determine it that accurately. So turning is a crapshoot. Say roughly a one in three chance that your turn will make it worse and put you under his bows.

That's what you aim to avoid by doing collision avoidance right, and at the proper distance away.
Maybe I'm just fooling myself but at a half mile away, I usually have a pretty good idea of a high speed yacht's heading relative to mine (assuming they don't change course). If it's that close that I might be wrong, either direction should work because they were coming right up my tail.

Of course, I'm used to congested waters and 100yds is typically plenty. Keeping a mile away is just unrealistic.
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Old 25-04-2016, 07:47   #73
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Re: Almost run over.

Saturday... I was out sailing. Very light winds, so I was going very slowly.

I saw a power boat coming a good distance off and figured if I maintained going straight we'd impact about 200 yds from where I was at the moment. So I turned 90 deg (which stopped my boat) to let them go.

Sure... I had the right of way.
It was just more practical to yield (probably before the other guy even noticed there might be an issue.)
I wasn't in a hurry to get to my funeral.

Everybody waved.
Happy happy happy. (Yes, I watched Duck Dynasty once)
Good to be out enjoying the water.
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Old 25-04-2016, 13:17   #74
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Re: Almost run over.

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Maybe I'm just fooling myself but at a half mile away, I usually have a pretty good idea of a high speed yacht's heading relative to mine (assuming they don't change course). If it's that close that I might be wrong, either direction should work because they were coming right up my tail.

Of course, I'm used to congested waters and 100yds is typically plenty. Keeping a mile away is just unrealistic.
In congested waters and inside harbors, it does work differently.

If you're dealing with high speed power boats in congested waters with a big difference in speed, there is not actually very much you can do yourself anyway. They are steering around you, and whatever maneuvering you are doing is not influencing the crossing.

That's in fact the way we deal with the Red Jet ferries in the Solent. They make up to 40 knots, and our collision avoidance procedure is very simple -- just ignore them. They steer around us like playing a video game, and the encounter is entirely in their hands, as by the time we detect a potential problem, there is already no way any maneuver of ours will influence the crossing.

A boat full of French fishermen were killed in the Channel, by the way, a couple of years ago, run down by one of the fast cross-Channel ferries. There was nothing they could do. The ferry driver just screwed the pooch.
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Old 25-04-2016, 13:47   #75
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Re: Almost run over.

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In congested waters and inside harbors, it does work differently.

If you're dealing with high speed power boats in congested waters with a big difference in speed, there is not actually very much you can do yourself anyway. They are steering around you, and whatever maneuvering you are doing is not influencing the crossing.

That's in fact the way we deal with the Red Jet ferries in the Solent. They make up to 40 knots, and our collision avoidance procedure is very simple -- just ignore them. They steer around us like playing a video game, and the encounter is entirely in their hands, as by the time we detect a potential problem, there is already no way any maneuver of ours will influence the crossing.........................
That's true here on SF Bay, too. Of course only for the local ferries, not the big ships, who have their own channels. From what I've read, it is NOT true in NYC Harbor. So when you travel to different ports, be cautious.
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