Checking with the authorities in charge of the waters in which you will operate your vessel is ALWAYS advisable.
Yes, for night sailing.
Sailboats have many "poles". The ones that I think you are referring to are the mast and the boom. The Mast is the Tall one that sticks up out of the hull. The is connected horizontally to the mast.
A white mast light indicates that a given vessel is resting at anchor.
On a mooring none,if fishing or at anchor a white light at mast or stern.
This white-colored light that must be visible from all angles is called an anchor light. It is usually situated atop the mast.
A white light on a powerboat (that obviously doesn't have a mast) must be displayed so as to be visible from 360 degrees.
A masthead light is a white light located at the highest point of a vessel, typically on the mast or superstructure. It helps other vessels identify the boat's presence, direction of travel, and size when navigating in low visibility conditions. The masthead light is required by maritime regulations, especially at night or in restricted visibility.
You can make a plain white mast out of a few layers of white tee shirt. You cal also buy a sturdy plain white mast from a hardware store.
A boom is used to hold the foot, or bottom of the sail. It is attached to the mast, in various ways. It is simply a pole that stretches out the bottom of the sail to obtain better performance.
Locks the mast in the vertical position.
Two