What detimines whether an oject will sink or float is the amount of fluid that it displaces. If the amount of fluid displaced weighs more than the object then it will float, if it weghs less it will sink. A boat can be made of any material, even concrete.
Metal ships are built to float.
You can't make a bar of metal float on water, but boats with metal hulls float. Also, metal bars and other metal objects float on mercury.
Ships, whether made of wood or metal, have a lighter specific gravity than water. Ships actually displace the water rather than floating on it.
"average density" You must combine the weight of the metal hull with that of the air contained within it.
It depends. A steel ship will float just fine, so will an iron one(i.e. Old Ironsides). It all depends on the size, weight, and buoyancy of the ship.
It displaces water and is filled with air.
Metal ships float because they are designed to displace a volume of water greater than their own weight. This displacement creates an upward force known as buoyancy, which keeps the ship afloat. Additionally, the metal used in ship construction is carefully chosen and shaped to provide the necessary strength and buoyancy.
if you know how to ship make a metal boat then you will know how to make a wooden pirate ship.
Because the volume of water it displaces weighs more than the ship. Archimedes principle says that the upwards force on the ship is equal to the weight (mass) of fluid displaced - so the ship floats
They do not. A metal ball bearing with a weight of less than 1 Newton will sink in water but a ship weighing several thousand Newtons can float.
I can make a iron nail float. Simply melt some lead and the iron will float on top of the lead. Your question seems to be with regard to how do Boats float and the answer is Bouyancy. The Boat displaces a volume of water and if the weight of the displaced water is less than the weight of the boat, the boat will float.
Needles don't float because metal is very dense and contains no air. A boat is either made of porous wood which is lighter than water, or metal with air reserves to keep it afloat.