Some people believe that gravity doesn't exist

[notimportant1234]

There are other factors that determine a ships shape like stability, velocity. But the most important is flotability.

The amount of water a ship 'dislocates' is a function of its mass and fuck all to do with the shape of its hull.

In other words, for an object floating on a liquid surface (like a boat) or floating submerged in a fluid (like a submarine in water or  in air) the weight of the displaced liquid equals the weight of the object. Thus, only in the special case of floating does the buoyant force acting on an object equal the objects weight. Consider a 1-ton block of solid iron. As iron is nearly eight times as dense as water, it displaces only 1/8 ton of water when submerged, which is not enough to keep it afloat. Suppose the same iron block is reshaped into a bowl. It still weighs 1 ton, but when it is put in water, it displaces a greater volume of water than when it was a block. The deeper the iron bowl is immersed, the more water it displaces, and the greater the buoyant force acting on it. When the buoyant force equals 1 ton, it will sink no farther.
https://en.m.wikipedia.org/wiki/Archimedes%27_principle

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There is no gravity. The Earth just sucks.

Boru

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That is the trick with Arhimedes Force = (-1) x amount of water dislocated × gravitational acceleration.
If gravity doesn't exist ships would never float . The shape of a ship is made the way it is with the purpouse of dislocating more water.

If that's true, all ships would be the same shape. Since a Viking longship is manifestly not the same shape as a Nile River barge, you seem to be mistaken. 

Boru

When they solve the flotability problem , they modify the shape for other aspects as velocity, stability etc.

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Succubus you seem to not know the formula of mass= volum times density.