Thank you for the help!
It is on the other face.
I need to cut out the rectangle width, 5 mm wide in the center, through
the nose of the end, on the angle of the guide lines.
Messy? Not surprised; I have not much experience with CAD and have only
had this program for 2 days... I thought I was doing not bad. LOL
This is a part from my kayak that broke and impossible to find. My
intention is to try to reconstruct. it with a 3d printer.