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Old 10-10-2008, 15:49   #106
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More Questions.

Like most sailing/motor vessels (super yachts) of this size, MF would have had the motor running, to not only run sailing gear, but to add maneuverability in what was potentially a confined and congested area. Does this make a difference?
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Old 10-10-2008, 16:53   #107
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Originally Posted by imagine2frolic View Post
As most know if you are too close to a wall. The wall can actually suck you into the wall itself. A prime example is the south tower on the Golden Gate. It is known to eat boats. I am wondering if this same force would come into play with MF being nearly a wall, although a moving wall?
I understand what you are saying. I'm going to talk theory here about something I know little about. But that hasn't stopped me before. So, why should I attempt sound judgment at this late date?

The reason a wall can suck you in is: Well, the wall itself doesn't do it. But a wall, especially extending to the bottom, can affect currents. And currents don't go just parallel to the surface, they can go vertical. As the water hits the wall, depending on angles, bottom, etc, the water may roll from the surface downward. This means the water at the surface, rather than following the wall, is actually moving towards the wall. Basically, the surface is moving towards the wall, but the water under the surface is either moving parallel to the wall or back outwards. At the surface, your boat is sucked towards the wall.

So how does this apply to a ship? That would depend on the size of the ship, how far below the surface the sides go and how it's shaped.

I can understand this effect possibly from a large freighter in a cross current with straight sides extending 14ft below the surface, but I think the effect would be minimal on even a large sailboat. That is, any effect would probably only extend out a few feet. I would feel pretty safe saying the effect should extend less than 20-30 feet. And at 20-30 feet it would be subtle.

So, in short, I can't see how this effect would have any significant effect on SB and it's maneuvering until almost at the point of impact. That is, if indeed there is really any effect present on a forward moving efficient hull with or without a cross current. A sailboat is specifically designed to move as little water as possible, and to have that movement be as close to parallel to the hull as possible. And it is designed to try to have the same pressure down the length of the hull (it doesn't displace a lot of water at once, but slowly moves it farther and farther from the centerline of the hull, and then allows it to slowly resume it's original position). I would think the natural current would generally be somewhat static in relation to the hull sides.

Remember, this is all just me theorizing based on my limited knowledge of physics and boat design, and trying to visualize how water would move in those circumstances.

So, I2F, does that sound in the least plausible?

-dan
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Old 10-10-2008, 18:24   #108
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Originally Posted by swagman View Post
Jeez Kevin,
Looks like you sucked me back into your debate.
From the statement you give above it sounds to me like the skipper of MF saw the smaller yacht approachh on stb and bear away to pass the stern of MF and in his opinion pass 200 yard behind.
Is that in those circumstances - in my opinion - a safe distance?

Er. Yes.

JOHN
John,

200 yards astern is a safe distance - but he didn't say yards; he said 200 feet. Also since Maltese Falcon was almost certainly the faster of the two, the CPA could not possibly be astern of MF.
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Old 10-10-2008, 18:30   #109
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Actually, the Colregs demarcation line is outside of the San Francisco Bay, so the Colregs don't apply.
The term "colregs" is colloquial and can easily be applied to the US Inland rules too. Both IRPCS and USINR have the same rule 18. As far as I can recall, Inland rules don't give big sailboats special privileges either.
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Old 10-10-2008, 18:40   #110
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Month after month in Lat38 there would be arguments that I am a sailboat. I have the right away. Most ignoring the fact that large boats have more restrictions in maneuvering, and that changes everything.
You're arguing apples to watermelons - what restrictions in manoeuvring did MF have? Why was she unable to give way as required by rule 12? If Perkins had done everything by the book, we wouldn't be having this discussion, but he as much as admitted to taking insufficient action.
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Old 10-10-2008, 18:52   #111
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ships suck

dan and frolic,

Ship pressure and suction zones are well-established phenomena. As a ship moves through the water it develops pressure zones at the bow and stern, and suction-zones along the mid-section. The larger the ship, the greater the effect. Speed and water depth also affect this. The same basic concept also applies where fast moving water flows past walls and the like. MF most certainly would have pressure and suction zones - whether they were strong enough to suck SB in is a matter of conjecture.

Kevin
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Old 10-10-2008, 20:08   #112
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Did no one think of wind shadow?

As far as suction goes....it is a real and eerie thing. The first time I experienced it on a tug (as we came along side to put up the docking pilot) was a sense of real powerlessness....then you get used to it and anticipate and plan how you will manoeuvre away
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Old 10-10-2008, 20:17   #113
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Just seen this and the pictures without knowing the full story it looks a simple case of Port boat not giving way to one on Stb. BUT and it's a big one, was the Port Hand boat given time to give way, as is required? It appears it may not have been.

I very much doubt MF had any restricted manoeuvring issues. If she did someone needs a good kick in the arse for being under full sail at speed. It certianly doesn't appear that comes into it. If I saw her going like that it would be real easy to think she wasn't restricted in any way.

Seems a case of situational awareness wasn't high, maybe on both boats.

What an expensive lesson for someone.
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Old 10-10-2008, 21:06   #114
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It's interesting that we have 3 schools of thought going.

1 - Little ships should get out of the way of big ships
2 - Little ships have rights as established in ColRegs
3 - Little ships have rights but they should still get out of the way

I only sided with SB because the immediate media response was, "Little ship slams into big ship."

There are rules and regs. You either believe they apply or you don't. Or you think they apply except in extenuating circumstances. That's not a good idea to boild a foundation of rules on.

Should the SB see the 300 foot ship - Yes. Could the SB maneuver out of the way - yes. Is it hard to maneuver a 300 foot ship out of the way of a 40 foot ship - yes.

I stick by my previous opinion. MF was going to fast. She should have been short sailed or motoring. SB had the last chance to avoid collision.

Both at fault.
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Old 10-10-2008, 21:49   #115
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The rules are the rules and while there are 'size breaks' in many ports, size shouldn't come into it at all unless it is a local by-law thingy. Here in Akl the Harbour rules say over 500tonnes has some extra rights over and above the ColRegs but that is mainly due to limited searoom. I don't know if MF was in an area like that there.

The rules say Port gives way to Stb. They don't say Big boats on Port can keep going as the Stb hand boat is smaller.

So assuming no local additional rules applied it should be pretty clear cut. If the little fella did give enough time for MF to take action and MF didn't take it, MF is at fault. It's pretty simple.

If the little fella didn't give MF enough time to give way by tacking onto Stb too close, she's needs a smacking.

Having driven many a weird vessel in harbours I know it can be bloody hard work keeping clear even if in the right. Often I've changed course to miss boats even though I had the right of way. It's called situational awareness. As in many situations I'm sure the other boat had no awareness of the bloody rules.

There shouldn't be any 'schools of thought' and size has little to do with it.

Actually size does matter in reality for 2 reasons.
1 - MF is one big beast and the skipper (whom I told is a bloody great bloke and knows the game very well) will have been well aware many boats on many harbours just don't know the rules. Hence he should have been prepared to make manoeuvres very fast. If not because of the rules but more because of the lack of them in the boats around him. Sailing at full titty under full rig seems to suggest he wasn't to well set to make a crash tack or very fast course change if required.
2 - any thinking boater should be able to work out MF can't tack inside a minute or 2 so pure common courtesy would dictate other (big or small) boats either give a lot more time or just stand clear even if they do have the rights under the ColRegs.
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Old 11-10-2008, 00:58   #116
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Quote:
Originally Posted by Lodesman View Post
John,

200 yards astern is a safe distance - but he didn't say yards; he said 200 feet. Also since Maltese Falcon was almost certainly the faster of the two, the CPA could not possibly be astern of MF.
Kev, 200 yars, 200 feet, 30 feet. All are a safe distance for the smaller yacht to sail past the stern of the bigger one - if that is what both aimed to do safely.

If your point in all this is to ensure others understand the 'rules' - then make sure you remind all that neither yacht has the right to hit the other - and I trust you're not suggesting from the pictures than MF hit the smaller yacht? Or maybe you are......

So again - suggest we wait for the inquiry to see who was actually at fault.

Cheers

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Old 11-10-2008, 04:24   #117
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...MF would have had the motor running...
I don't think it would have been motoring, although there probably was one (or more) gensets and the like running. Had their engine been engaged, they would have flown a day-shape and then really changed their right-of-way situation since they would have become a powerboat. I think that with sufficient wind to be maneuverable the Maltese Falcon would be unlikely to have been under power.
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Old 11-10-2008, 06:19   #118
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Kev, 200 yars, 200 feet, 30 feet. All are a safe distance for the smaller yacht to sail past the stern of the bigger one - if that is what both aimed to do safely.
Bollocks - SB was going a fraction of the speed of MF - for her to pass 200 ft astern, she has to pass 50 ft on the beam. Basic relative velocity.

Quote:
If your point in all this is to ensure others understand the 'rules' - then make sure you remind all that neither yacht has the right to hit the other - and I trust you're not suggesting from the pictures than MF hit the smaller yacht? Or maybe you are......
Again, my boat doesn't have brakes. Where can I get some? Or do you believe SB intentionally rammed MF? The fact that SB's bow hit MF's side is a factor of timing, not fault.

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So again - suggest we wait for the inquiry to see who was actually at fault.
Sounds fair to me.

Cheers

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Old 11-10-2008, 07:54   #119
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You're arguing apples to watermelons - what restrictions in manoeuvring did MF have? Why was she unable to give way as required by rule 12? If Perkins had done everything by the book, we wouldn't be having this discussion, but he as much as admitted to taking insufficient action.
On the Bay there are many restrictions for a boat of such size, and it's capabilities to maneuver. Also this photo is from above, and we can clearly see MF is pinched. This could be the same scenario that we cannot see because the sequence of photos is from just above the water. I am not siding with either. I am just throwing thoughts out there, and reading along. So basically it is not apples, and oranges. Especially after sailing those water for 13 years continuously I do have a wee bit of knowledge of the area.
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Old 11-10-2008, 10:16   #120
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Also this photo is from above, and we can clearly see MF is pinched.
This photo (in the preceeding post) is not of the SB that collided with the MF, but it does show the kind of traffic that MF had to contend with.

From seeing the photo sequence of the collision, and from the remarks of the photographer, I believe that the SB was on starboard tack, with clearance appropriate for the conditions. They then turned onto a collision course with MF, giving MF insufficient time to respond. If MF had turned to port, their stern would have swung into the approaching SB, possibly making the collision worse.

Just my opinion, of course, I wasn't there.

When sailing on S.F. bay, I experience a similar situation, with me being the less-maneuverable boat, when the sailboarders start zipping around. They sail so fast (compared to me) and change course so quickly and unpredictably that it is safest for me to just hold my course in a questionable situation, regardless of which tack I am on.
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