My main difficulty was keeping it within the word limit. I have posted mine below. As you can see it is intensely personal, so you will have to craft it to your personal experience, biography, etc.
Motivational statement:
I have a great deal to offer the U.S. Navy as an officer candidate. Leadership, morality, dedication, intellect, motivation, ethics, strength of character, and life experience are all qualities and skills that I possess. Throughout my life I have been a leader of my peers, and I have refined my innate leadership skills through formal education and training. I am a master at motivating myself and others to succeed, and as a professional educator I have a great deal of experience doing so. My strong morality and ethics are apparent when considering my dedication to helping others and active positive contribution to society as an educator and through years of community service. I have helped to motivate, inspire, and educate a diverse number of people throughout my life. I have worked closely with people of many different ethnicities, backgrounds, and creeds, cultivating a philosophy of awareness and respect. As a Navy officer, I will utilize my skills as a leader and motivator of people to catalyze those around me to succeed at the highest level.
My dedication to the U. S. Navy has been a life-long theme. A deep respect for the armed forces, and the Navy in particular, was cultivated within me at an early age. There is a proud tradition of naval service in my family's history. I have always had great respect for my elder family members, and this respect extends to their involvements and accomplishments. My grandfather was the leader of his Navy unit while serving overseas during World War II, and my great grandfather was a Navy doctor during World War I. Following World War I, the U.S.S. Parrott destroyer, named in honor of one of my relatives who gave his life serving in the Navy during World War I, was commissioned by the Navy.
Besides my family's tradition of Navy service, I also have various other personal reasons for wanting to serve. I see it as a great honor and privilege to serve the United States as an officer in the armed forces. It is my duty as an American, I believe, to serve my country and help secure a promising future for contemporary people and those to come. I possess the personal and professional qualities that are necessary to become an exemplary officer in the U.S. Navy, and sincerely hope that I am granted the honor of serving in the world's greatest military.