We
use the space inside the mast for stowing a sail. This is very simple to
understand and to use.
The masthead is open like a funnel. To help the sail in we have a rope (halyard?) from the top of the sail lead through the opening.
This rope is brought all the way down to the bottom of the mast where there is a block. From this the rope is lead up and out of an opening at a convenient distance above deck where you will be standing to take care of this rope.
If
you pull this rope the whole sail will be hidden inside the mast. From the
masthead you then have the sheets to be handled in a normal way when sailing.
As protection there is a cover which is attached between the sail and a sheet and forced into the opening after the sail has been lead inside the mast when pulling the rope.