The mast of a ship is very important to the movement and navigation of the ship.
You are describing the mast.
A jack that was supposed to be used for house construction.
The main mast is the tallest of all masts on the ship. If all masts are the same height, then the one with the top navigationlight is the main mast. If there is only one mast, then that would be the main mast.
A mast
the lookout who was stationed at the top of the mast
The ship's mast stood tall against the clear blue sky.
A mast
mast
No it is not.
mast
16'7".359