Abort Point and Point of no Return

What is Abort Point and Point of no Return ?

When approaching constrained waters, the ship may be in a position, beyond which it will not be possible to do anything else, other than proceed.

         Termed the Point of No Return, it will be the position where the ship enters water so narrow that there is no room to return or where it is not possible to retrace the track due to falling tide and insufficient UKC.

         A position needs to be drawn on the chart showing the last point at which the passage can be aborted and the ship not commits herself.