How did a piece of ice cut through the solid steel hull of the Titanic?
In: Physics
Cars are very strong and if you took a knife to a car you would be wasting your time aside from some paint damage.
But if your car hits a brick wall even at a fairly low speed it is going to do a lot of damage.
The same principle applied here. The iceberg was very big and had significantly more mass than the titanic. And it was hard enough that even though it wasn’t as tough as the relatively thin plate of steel, the in plate of steel still gave more under all of the insanely high amount of mass both objects were colliding with.
It didn’t cut through, it ripped through.
Ice is softer than steel, but the pressure that the ice applies to the side of the hull is a force x the area it gets spread over. A knife cuts because it concentrates a small amount of force onto a very very tiny area (the cutting edge of the blade). In the case of the iceberg, the pressure of the collision was huge, because it was a large iceberg, so that pressure pushed in the steel plates and dented them, and they basically popped out at the seams and let the water in.
The force needed to move the iceberg was more than the force needed to pop the rivets and bend the steel.
If I’m recalling correctly, they were going faster than they should have been knowing there was ice in the area and icebergs are (can be) massive. based on survivor accounts and the typical scale of icebergs (above and below) water, they say the thing was like 2 million tons.
If you want a more in depth answer, Oceanliner Designs has a few excellent videos on YouTube.
You are thinking in terms of cutting but the answer has more to do with crushing (think hammer, not knife).
The size and mass of the iceberg that hit the Titanic can only be estimated, but the survivors’ accounts describe it looming over the foredeck of the ship — so 50 to 100 feet high, several times that long, and an unknown amount under the water. Because it was solid ice rather than mostly empty space like the Titanic, the iceberg could easily have massed far more than the ship.
On top of that, unlike a battleship of the period, Titanic’s hull was not actually designed to fend off impacts. It was designed to hold the ship together as economically as possible. In a collision between a very large iceberg and a large ship, the physics are not like a knife cutting through an object. The physics are more like a car driving into a wall at high speed. Whether it’s made of steel or plastic, the car’s structure will suffer from that impact.
The Titanic’s hull was riveted, the bulk heads were crushed then torn by hitting a mass that was greater than the mass of the ship.
How do you cut a diamond, if it’s the toughest material (known to exist)?
Same answer: Nothing is indestuctible, but it takes off more material off the grinding “stone” than the diamond.
Steel/iron is harder than ice, but the amount of ice is thoundsans of times bigger.
The iceberg was an immoveable object for their mass and speed, but their mass and speed was to high to deflect using the strength of the steel, so it didn’t cut, it rended the steel apart, at the rivets and pulled it form the hull plates and it lost structural integrity. The visible iceberg was twice as high as the ship, but thats only 10% of the mass of the iceberg and doesn’t include the water being displaced
By not moving out of the way.
Both objects were so heavy and traveling at a high relative velocity that it wasn’t possible to slow down upon impact. Instead, the steel side of the ship bent and buckled while the rest of the ship kept going behind it. It surely also broke big hunks out of the iceberg, but again the iceberg is too big to either get pushed out of the way or disintegrated completely.
Crunch.
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