This book was written for the needs of Cadet Captains of the Naval Academies. The content has been written according to the requirements of the International Convention STCW for the training of Cadets attending these institutions. Shipping is a common ground for all of us who have traveled from whatever homeland we come from, which is why the content was not written from memory but various sources were used, which are referenced at the end of the book. Many of the diagrams I created myself using computer techniques and others I found in books and on the internet. The aim of the book is to help our students - the future captains of commercial ships - to understand so that they can later use the methods of creating and maintaining the stability of their vessel.