Unrestricted Line Officers (URL Officers) are Officers of the Line in the U.S. Navy who are qualified to command ships and aviation squadrons. URL officers include officers from the Surface Warfare, Submarine Warfare, Aviation, and Special Warfare communities. In contrast to Limited Duty Officers, Unrestricted Line Officers are required to have at least a Bachelor's Degree. They are commissioned through programs such as the Navy ROTC (including Seaman to Admiral-21), the Naval Academy, and Officer Candidate School. The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ... A Limited Duty Officer (LDO) is an officer in the U.S. Navy or U.S. Marine Corps who was selected for commissioning based on his skill and expertise, and is not required to have a Bachelors Degree. ... The examples and perspective in this article or section may not represent a worldwide view. ... The Reserve Officer Training Corps (ROTC) is a training program of the United States armed forces present on college campuses to recruit and educate commissioned officers. ... The United States Naval Academy (USNA) is an institution for the undergraduate education of officers of the United States Navy and Marine Corps and is located in Annapolis, Maryland and Washington D.C. The Academy is often referred to simply as Annapolis although naval officers normally refer to it in... In the United States armed forces, Officer Candidate School (OCS) or the equivalent is a training program for non-commissioned officers, soldiers, Sailors, Marines, Airmen and recent college graduates to earn commissions as officers. ...

History

Originally, there were two kinds of officers on a ship, the commanding officers, who were "gentlemen" and commanded the ship, and the warrant officers, who were technical specialists who ran important tasks. In the Nineteenth Century, with the introduction of steam power, a third group of officers developed, engineers, who ran the steam plant. As the technology developed, the engineers were requesting more rights, including command. Eventually, this dispute led the Department of the Navy to abolish the differences between the groups, amalgamating them into Unrestriced Line Officers. This fact can lead to confusion with non-American naval personnel, lacking the division between the two groups. The Russian Navy is an example of one with a difference between Deck and Engineer officers. A Warrant Officer (WO) is a member of a military organization holding one of a specific group of ranks. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... A steam engine is a heat engine that makes use of the potential energy that exists as pressure in steam, converting it to mechanical work. ... Russian Navy Jack Russian Navy Ensign The Naval Cathedral in St Petersburg is the main church of the Russian Navy. ...