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The Sinking of MS Estonia: Case Re-opened Part II

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Vixen said:
Take a simple rowing boat, wood frame, operated by oars. There are no leaks.
Any imbalance or inflow of water, the boat simply capsizes toppling its contents into the water. It doesn't sink, it floats upside down ceteris paribus.
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Non sequitur; a waste of perfectly good electrons.
 
JayUtah said:
Capsizing requires a roll moment. This source does not discuss that. Show us, preferably with a vector diagram relating the center of gravity to the center of buoyancy, how a ship that fills with water will inevitably capsize. Show us the roll moment.
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We were talking about capsizing right, when the trim (centre of gravity) is displaced (listing). When a vessel lists at 90° it capsizes belly up. If it has a superstructure such as a liner or cruiser, then the amount of time it takes water to displace the air guides you as to how long before it sinks.

Of course, if you cynically believe that artificially pouring water into it to the brim or adding 40K or iron ore, as someone claiming to be an expert suggested, you are merely cheating instead of truthfully acknowledging the case.
 
LondonJohn said:
It was Roman. And you did get a reply. Go back and read more carefully.






So you'd presumably also agree that "bunging" around 10,000 tons of seawater onto a ship will probably sink it?






What the heck are you talking about? The Roman ship in question was carrying a cargo of amphorae. That's the sort of thing that cargo ships generally did in Roman times. The ship wasn't overloaded until it took on so much water that the combined mass of water + amphorae exceeded the buoyancy limit of the vessel, whereupon it sank. Straight downwards to the seabed. In exactly the same orientation & attitude as it had had at the surface: horizontal from bow to stern and along each crossbeam, and keel-low.

Similarly, the Estonia was not overloaded when it was just carrying its own mass plus vehicles and passengers. But when it additionally took on a huge mass of water (via the compromised bow opening), it reached a point where the combined mass of ship + passengers + vehicles + seawater exceeded the buoyancy limit of the ship*. And can you hazard a guess as to what happened next...?


* In the case of the Estonia, it's a little more complicated, owing to the destabilisation of the ship's attitude as the seawater on the vehicle deck rushed from side to side and bow to stern. But the general principle still holds just fine.
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Do look up how bulkheads in the hull add to the buoyancy of a ship. Stop harping on about overloading the wretched thing and thereby claiming that elementary laws of physics do not apply. (Short answer: they do.)

Look up Vasa to find out why it sank.
 
Myriad said:
I have a simple rowing boat operated by oars. It's metal, not wood, which is more similar to Estonia.

I also have a small dock on a tidal body of water, which would allow me to experiment at will with plenty of depth to sink the boat at high tide, and still recover it easily at low tide.

I have a bucket, with which I can progressively fill the boat with water in whatever unbalanced manner you specify.

I have a video camera.

What test would you like me to perform, what outcome do you predict, and what would you like to bet on that outcome?

Make it worth my while. The water's getting colder by the day, this time of year.
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May I politely suggest you look up the priniciples of displacement of air so that you have a better understanding of what happens when you carefully load up your boat with the aim of making it sink?

Anyone can deliberately crash a car or an aeroplane but it doesn't mean you've outwitted the designers.
 
Vixen said:
Do look up how bulkheads in the hull add to the buoyancy of a ship. Stop harping on about overloading the wretched thing and thereby claiming that elementary laws of physics do not apply. (Short answer: they do.)

Look up Vasa to find out why it sank.
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Citation for the highlighted, please. I'm no expert, but I'm pretty damn sure that bulkheads do no such thing.

It's not best of sources, here's what wikipedia has to say about the purpose of bulkheads:

Bulkheads in a ship serve several purposes:

• increase the structural rigidity of the vessel,
• divide functional areas into rooms and
• create watertight compartments that can contain water in the case of a hull breach or other leak.
• some bulkheads and decks are fire-resistance rated to achieve compartmentalisation, a passive fire protection measure; see firewall (construction).
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Nothing about adding buoyancy there, but maybe your source wasn't wikipedia.
 
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junkshop said:
Citation for the highlighted, please. I'm no expert, but I'm pretty damn sure that bulkheads do no such thing.

It's not best of sources, here's what wikipedia has to say about the purpose of bulkheads:



Nothing about adding buoyancy there…
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Well, I suppose the third bullet point is, to some extent.

For some reason the car decks of ferries tend not to have a lot of bulkheads across them.
 
Vixen said:
Do look up how bulkheads in the hull add to the buoyancy of a ship. Stop harping on about overloading the wretched thing and thereby claiming that elementary laws of physics do not apply. (Short answer: they do.)

Look up Vasa to find out why it sank.
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Are you still not aware that one can overload a vessel by introducing a large mass of water into it?

Are you still not aware that on the night the Estonia sank, it was overloaded because a large mass of water was allowed to enter into it?

I think we're about done here. You do not know what you're talking about.
 
Vixen said:
Longboats had sails, did they not?
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1) Longboats did not use the same sort of sail as a typical contemporary yacht (longboats were square-rigged from a centre mast*, which means they did not lean side-to-side from wind action on the sail).

2) In storms and rough seas, Viking sailors would have de-rigged the ship in any case.

3) Open-decked ships (including longships) most often sank (in a non-combat and non-collision situation) because they became overwhelmed by rough seas breaching the free board and cascading into the open hull. The ever-increasing mass of this water eventually overcame the buoyancy limit of the ship. And from that point onwards, there was only ever going to be one outcome: the ship was going to sink. And they frequently sank straight down without capsizing.

I've seen the remains of two such ships with my own eyes, and I've provided you with a photograph of one. What you saw in that photograph would have been a literal impossibility if the ship had capsized (let alone capsized then turned totally upside down), because the amphorae would then have been scattered in a haphazard fashion on the seabed - rather than in the neat ship-shaped order in which they were actually found.

You don't know what you're talking about.


* I don't really expect you to understand this point and its significance here, but you never know.....
 
Vixen said:
Of course it will sink if you deliberately add surplus weight to it whilst keeping it balanced.
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Just roll it enough to put one of the gunwales under, it will sink when it fills up with water.

Why are you obsessed with boats turning turtle?
 
Vixen said:
May I politely suggest you look up the priniciples of displacement of air so that you have a better understanding of what happens when you carefully load up your boat with the aim of making it sink?

Anyone can deliberately crash a car or an aeroplane but it doesn't mean you've outwitted the designers.
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1) What happens when you load up a ship (with a heavy mass of water) with the unintended consequence of making it sink?

2) Your insistence on sticking to this "displacement of air" nonsense is getting you precisely nowhere. As I've told you before: the placement of just one cubic metre of uranium into the hull of a 100ft yacht would make it sink, while displacing hardly any air from the hull.

You don't know what you're talking about.
 
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