According to the book Cheaper by the Dozen, “good sailors always make the mooring on the first try.” This quote can be found on the second page of Chapter 12. Different volumes of the book will have different page numbers.
In this chapter, Dad has bought a small sailboat for the children as a reward for them learning to swim. Before he will let them actually try to sail the boat, he puts them through an extensive training course on how to handle it. He takes the children out on the porch of their cottage in Nantucket (the Shoe) and pretends that they are on the boat. He puts them through drills so they will know what to do when they are actually sailing.
In the process of doing these drills, he tells them that good sailors always make the mooring on the first try. A mooring is a buoy anchored out in the water. A sailboat sails up and the crew ties it to the buoy. Since sailboats do not have engines, it is not completely easy to get close to the buoy and tie up to it on the first try. Dad wants the kids to learn how to do that because he says that is the mark of a good sailor.
You can watch a video about how to moor your sailboat in the link below.