Yeah!! What do you think they will do without them!
its sails
The correct spelling is "sailboat" (boat propelled by sails).
boom or mast
the single vertical pole is the mast
It is called the mast
Yes! -Over time, they stretch!
It is called mast.
It is called the mast
It holds (supports) the sails. You can also mount navigation systems on it.
They act as aerofoils, much like the wings of an aeroplane, and work by the air pressure difference on the surfaces of the sails.
Mast, spar or boom all fit this description.
A sailboat can certainly be operating under sail at night. Sailboats use their sails when there is enough wind to carry them.