Cont: The Sinking of MS Estonia: Case Re-opened Part III

[Jack by the hedge]

Every time I see this name ...

I mix it up with Anders Lindman, who brought a wildly fantastical element to any thread he joined. No conspiracy theory too bonkers.

 

[Mojo]

Surely that is not beyond your ken?

I’ve asked our Ken*, and he says he needs you to explain it for him.




*Do you know Ken Peel?

 

[Myriad]

Surely that is not beyond your ken?

My kenning is as sharp as a fist-tooth hewn from spark striker, and my similes aren't bad either. Thanks for asking. But, what does it mean when the center of mass is significantly above the center of buoyancy?

 

[phiwum]

As a service to this discussion, I conducted an experiment of sorts this summer.

My dear catboat was struck by lightning this summer. The bolt went straight down the mast and out through the hull, leaving a hole right at the the peak of the bow, about three inches long and around a finger's width at its widest point. (My boat is a catboat, with the mast way forward, so the hole ended up inches below the water right at the bow.)

I didn't know about the strike for about 18 hours, when I received a phone call that the boat was sitting low as if it was taking on water. When I arrived, a friend had already been there and with the help of the marina staff, towed it to the dock. There was a foot of water in the cabin.

Now, I didn't complete the experiment and let it sink. We pumped the water and (eventually) discovered the leak and had it towed. But in many ways, I had created a miniature version of the bow visor falling off a ferry. There are two big differences between my little experiment and the ferry. First, the hole was below the waterline and second there was not much in the way of waves (the big storm was actually due the next day).

But roughly the principle is the same. Water flowed in through the bow (in Estonia's case, it was due to waves that were above the waterline of the ferry). The Estonia heeled over due to the wave action and the mass of water inside, which didn't happen to my boat. Had I not been notified of the leak, my boat would have sunk without turtling. Fortunately, my hole was not so large as a bow visor.

So, there you have it. No need to scoop water into a dinghy and see what happens. I sacrificed the better part of my sailing season just to see what happens.

But my boat will be on the water next year. Thank goodness that insurance covers acts of nature.

 

[junkshop]

... Thank goodness that insurance covers acts of nature.

You have a very generous insurance company. If I were in their place, I'm not sure I would class the Mighty Thor* getting off a few practice shots before the storm proper hits as an act of 'nature'.



*or Zeus, I seem to recall that he's partial to chucking the odd thunderbolt around.

 

[zooterkin]

Surely that is not beyond your ken?

No, nor is it round the horne.

But do you know the answer?

 

[phiwum]

You have a very generous insurance company. If I were in their place, I'm not sure I would class the Mighty Thor* getting off a few practice shots before the storm proper hits as an act of 'nature'.



*or Zeus, I seem to recall that he's partial to chucking the odd thunderbolt around.

A catboat traditionally has a fairly stubby mast. There were a number of sloops nearby with taller masts. The lightning was just spiteful.

 

[abaddon]

I mix it up with Anders Lindman, who brought a wildly fantastical element to any thread he joined. No conspiracy theory too bonkers.

Lindman was mostly about cosmology and quantum woo. Bjorkman was or is so nutty that he bought a ban on Simon Shack's cluesforum. He was too nutty for a site that thinks pretty much everything is faked. That takes some doing.

 

[junkshop]

A catboat traditionally has a fairly stubby mast. There were a number of sloops nearby with taller masts. The lightning was just spiteful.

Perhaps, or maybe you didn't prostrate yourself quite low enough, maybe your praise wasn't quite heartfelt enough, or was dedicated to the wrong deity? Gods have feelings too, you know. It's not all about you and your boat. Heck, you should consider yourself blessed that the Mighty Thor (or Zeus, or whoever) considered your boat a worthy target for their divine attentions.

Get over yourself.

 

[GlennB]

I'm fairly sure Vixen could answer Myriad's question, but fears the follow-up question that would wreck Vixen's 'must turn turtle' claim.

 

[Vixen]

So when asked to think for yourself, you simply cite your discredited source once again and wash your hands of it? Is that what's happening here?

You're being asked questions to test your knowledge, Vixen. What does "lack of stability" look like in terms of center of gravity and center of buoyancy? What defines where those points are? What -- as you claim -- makes "center of gravity less than zero?" What forces act effectively at those points? How are they defined? What dictates the magnitudes of those forces? How do the points and forces combine to create (or deny) stability? What factors of a sinking ship affect all those physical parameters?

C'mon, Vixen. Now's your chance to shine. Show us that those "five years of physics" weren't wasted.

If you are expecting me to fill these pages up with formulae and graphics, you will be sorely disappointed. Those who really want to understand the concepts of buoyancy, centre of gravity, stability and instabilty and the metacentre in respect of boats and ships, this youtube video should help.

 

[Vixen]

As a service to this discussion, I conducted an experiment of sorts this summer.

My dear catboat was struck by lightning this summer. The bolt went straight down the mast and out through the hull, leaving a hole right at the the peak of the bow, about three inches long and around a finger's width at its widest point. (My boat is a catboat, with the mast way forward, so the hole ended up inches below the water right at the bow.)

I didn't know about the strike for about 18 hours, when I received a phone call that the boat was sitting low as if it was taking on water. When I arrived, a friend had already been there and with the help of the marina staff, towed it to the dock. There was a foot of water in the cabin.

Now, I didn't complete the experiment and let it sink. We pumped the water and (eventually) discovered the leak and had it towed. But in many ways, I had created a miniature version of the bow visor falling off a ferry. There are two big differences between my little experiment and the ferry. First, the hole was below the waterline and second there was not much in the way of waves (the big storm was actually due the next day).

But roughly the principle is the same. Water flowed in through the bow (in Estonia's case, it was due to waves that were above the waterline of the ferry). The Estonia heeled over due to the wave action and the mass of water inside, which didn't happen to my boat. Had I not been notified of the leak, my boat would have sunk without turtling. Fortunately, my hole was not so large as a bow visor.

So, there you have it. No need to scoop water into a dinghy and see what happens. I sacrificed the better part of my sailing season just to see what happens.

But my boat will be on the water next year. Thank goodness that insurance covers acts of nature.

Sorry to hear about your catboat. If the hole was below the waterline then not sure why it turtle after capsizing?

Here's a visual of a sailboat being struck by lightning and what it might look like.

 

[Vixen]

A catboat traditionally has a fairly stubby mast. There were a number of sloops nearby with taller masts. The lightning was just spiteful.

Spooky. <sfx theme from the Twilight Zone>

 

[Vixen]

Lindman was mostly about cosmology and quantum woo. Bjorkman was or is so nutty that he bought a ban on Simon Shack's cluesforum. He was too nutty for a site that thinks pretty much everything is faked. That takes some doing.

That's the Swedes for you.

:

 

[JayUtah]

If you are expecting me to fill these pages up with formulae and graphics, you will be sorely disappointed.

Yes. I am sorely disappointed. You tell us you have "five years" of physics education. You tell us that instead of just parroting outside sources unthinkingly, you prefer to think for yourself. But when push comes to shove, all you can do is post links to others' work without giving any indication that you understand what you're regurgitating.

Those who really want to understand the concepts of buoyancy, centre of gravity, stability and instabilty and the metacentre in respect of boats and ships, this youtube video should help.

Yes, the producer of that video has a decent enough grasp of stability in the roll axis to provide part of the explanation we asked you to give. However, that doesn't support your claim that a ship must inevitably capsize. In fact, it rather demonstrates otherwise. I guess you really can't think for yourself, otherwise you'd have noticed that there toward the end of your video.

Let's get something straight. You're not the teacher here. You're dabbling in things that I and others here are professionally qualified and licensed in. Continuing to pretend that you're dispensing wisdom to the benighted will not fix your problem.

 

[JayUtah]

That's the Swedes for you.

:

So I'm looking at the gorilla in the room. At this point, how much of your performance here should be attributed to hatred of Sweden and the Swedes?

 

[zooterkin]

Sorry to hear about your catboat. If the hole was below the waterline then not sure why it turtle after capsizing?

It didn't. I suggest you read that post again.

 

[Vixen]

So I'm looking at the gorilla in the room. At this point, how much of your performance here should be attributed to hatred of Sweden and the Swedes?

We love the Swedes...except when it comes to Ice Hockey.

 

[Jack by the hedge]

Sorry to hear about your catboat. If the hole was below the waterline then not sure why it turtle after capsizing?

If the hole was above the waterline, umm, where would they have buried the survivors? Or something.

A small hole below the waterline is just a way of water getting into the boat. It could as easily been waves lapping over the sides or rain falling into it. The problem is the same - water in the boat reducing its buoyancy. You appear to think the manner by which the water arrives is important to the manner in which the boat will settle lower in the water. If so, why?

 

[theprestige]

If the hole was above the waterline, umm, where would they have buried the survivors?

Grant's Tomb, obviously.