Submarines are designed with enough ballast and control systems to allow them to submerge and surface as needed.
Surface ships are designed only with enough ballast and control systems to keep them on the surface. While they can sink just as well as submarines can, their ability to re-surface without a salvage operation is non-existent.
Ships try to avoid sinking, submarines sink on purpose...
They caused anxiety and sink ships.
Ships don't sink because they are more boant then the water they float on. Ships don't sink because they are more boant then the water they float on.
To sink enemy vessels, ships or submarines.
sink allied supply ships to England
They were at war with each other.
Because they don't sink.
They were used mainly to sink enemy transport ships.
To stop supplies from reaching England
IJN & USN subs went looking for ships to sink.
They rise to the surface when air is pumped IN. They sink when air is let out
Provided the boats and the ships displace their weight in water without the water coming inboard, they will float and not sink. A boat made of wood is likely to float even when full of water because wood tends to float. It is all to do with displacement and freeboard.