How do 1000+ pound ships float?

bouyancy is acheived from creating a high pressure in the water below the boat. Enough pressure to keep the boat above water. This is because the hull displaces lots of water. all that water eventually equals the weight of the boat and a static state will become of the interference between the two. same reason that rock would float if it were shaped like a bowl.

The ship's weight is spread over a large surface which displaces water making the ship float. A rock is very dense so that it's weight is concentrated in a very small area.. Therefore, it doesn't displace enough water to support itself.

Simple. The water that the ship displaces weighs more than the boat, therefore it floats. When you look at a boat or ship, the notice the water line.. imagine the amount of water that's displaced by the boat - that water weighs more than the boat - since the boat is lighter... it floats.

By taking up more space than 1000+ pounds of water.

It is called Displacement. http://en.wikipedia.org/wiki/Displacement_hull There is a concrete boat that is in my town, it floats!

surface tension: water molecules have a way of sticking together -- like how water spilled on a level, flat surface (like your desktop) will form into connecting bits that try to stay together -- without surface tension the ship would fall through the water like it falls through air. The surface of the water pushes up on the ship with a force equal to the amount of water that the ship displaces (pushes out of the way). The ship is pushing down on the surface with a force equal to the weight of the ship (say, 1,000 lbs). When there is enough of the ship in the water (below the waterline) to displace 1000 lbs of water, the ship floats at that depth. by the way, a small ski boat weighs more than 1,000 pounds It takes about 16 cubic feet to displace 1,000 lbs of water (varies slightly depending on the temperature and salt/mineral content of the water). That's 8 feet by 2 feet by 1 foot.

i am sailing as Chief officer in tankers, so i guess i may be of some help to u..anyway to begin with , we will first consider the case of submarines, this can float and sink as well.... question is how and why....when submarines submerges, it uses all its ballast tanks to fill water, what it effectively achieves is reducing the volume compared to its weight(displacement), actual weight of the submarine never changes, ie weight of steel and associated equipments, but the submarine has effectively reduced its volume, and for surfacing it simple blows out it tanks and regains its original volume their by increasing its displacement, when the displaced water is equal or more than the real weight of submarine , buoyancy forces acts and brings submariner up. Going back to the original question, the rock only displaces the volume it occupies, and that volume of water is very much less than the weight of the rock, but a ship with its constructional features displaces exactly the same amount of water equal to its weight. if by any chance if you can make the rock lighter keeping its volume same, the rock will also float. Materiall floatation is related to its relative density , so if by construction if you can make it relatively less denser than water , anything can float.

If an object displaces an amount of water equal to it's weight, it will float. If an object displaces an amount of water less than it's weight, it will sink. In the case of the ship, the volume of water that the hull displaces allows it to float. In the case of a rock, it has a higher density than water and so the weight of the water it displaces by it's volume is less than the weight of the rock. A rock will float in a liquid which has a higher density than that of the rock.

size doesnt matter (in this case haha) it depends on the density of the ship