Quote:
Originally Posted by SkullWorks
to go back a couple pages....
Buoyancy, in order for something to float or be buoyant, it must displace it's own weight in water. this is why glaciers are "mostly" below the surface, ice expands somewhat when it freezes, so it now displaces more area than is equivalent to its weight in (fluid) water (it is still water).
so in order for something to float it's CofG above the waterline, it's density must be less than half that of water's
it would also require a huge base to prevent turtling,
commonly keels of ships are filled in large part with lead this lessens roll lowers CofG and allows the boat to still sail without cargo. (ever seen an empty cargo ship leave port it surely would topple with out a counter-weighted keel)
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In addition to a weighted keel, ships often use fuel oil and water as ballast. As ships use fuel, they take aboard seawater to maintain trim.