as far as holding "up" ... the mast is usually stepped (attached) to the deck or keel on a sailboat. this supports the gravity downward load.
to keep it from toppling over in the slightest breeze, there are wire rope stays connected at various points. in a masthead sloop there is a headstay and backstay connecting the front and back of the boat to the top of the mast. there are also shrouds (left and right) wire rope rigging (usually) that hold the mast up from the left and right.
there can also be attachments at the midheight of the mast for fore and aft shrouds as well.
A mast. Although it is attached to a mast the thing that holds a sail up is a halyard. a mast is something that pushes the boat with wind and the reason its called a mast is cause it holds the biggest sail, the thing your looking for is something that is on the bottom of the boat and runs vertical on the boat. if that gets ruined the boat is ruined, unrepairable
the pole that holds up the sail is called the mast
The pole you are referring to is called the mast. If the boat only has one mast it is usually not in the middle of the boat but is normally found in the forward third of the boat.
A pole on a boat that holds spars or sails.
The halyard (a line, NOT a rope) keeps it tied up to the mast (that vertical post-thing).
Stays support the mast on a sailing boat running from the mast forward and aft. Shrouds also support the mast and run from the mast to the sides of the boat.
Mast
It is called the mast
A sail-robber? No, it's a MAST!
The mast(s).
The ship or boat with sails is the yawl, which will typically have 2 sails, the main mast for the main sail and mizzen mast. A yawl is defined as a boat with the mizzen mast aft of the rudder post. A boat with two masts, a main mast and a mizzen mast with the mizzen mast forward of the rudder post is a ketch.
The lowest portion of the ship is the hull. Also, the front of a boat is called the bow. The rear of a boat is called the stern. The sails holds the sail. The mast catches the wind.