Many milestones are completed between launching and commissioning of a ship. Below are just a few of them.
Sea trials are an intense series of tests to demonstrate the satisfactory operation of all installed shipboard equipment. Sea Trials ensure that the performance of the ship as a whole is in accordance with its plans and specifications. New construction ships undergo Builder's Trials and Acceptance Trials prior to ship's delivery and Final Contract Trials several months after delivery and sail away.
The ship's final departure from the construction yard for its homeport or commissioning site. It signifies the end of the new construction period and the beginning of its life preparing to perform the mission it was designed to undertake.
The commissioning ceremony marks the acceptance of a ship as a unit of the operating forces of the United States Navy. At the moment of breaking the commissioning pennant, the ship will "come alive" and the crew will ceremonially run aboard ship. Thereafter the ship is officially referred to as a United States Ship (USS).
The act of placing a ship in commission marks her entry into active Navy service. At the moment when the commissioning pennant is broken at the masthead, a ship becomes a Navy command in her own right, and takes her place alongside the other active ships of the Fleet.
This ceremony continues a tradition some three centuries old, observed by navies around the world, and by our own Navy since December 1775, when Alfred, the first ship of the Continental Navy, was commissioned at Philadelphia. Once in commission, the commanding officer and crew are entrusted with the privilege, and the responsibility, of maintaining their ship’s readiness in peace, and of conducting successful operations at sea in time of war.
No written procedure for commissioning was laid down in our Navy’s early days, but the act of commissioning was familiar, derived from established British naval custom. Commissionings were simple military ceremonies. The prospective commanding officer came on board, called the crew to quarters, and formally read the orders appointing him to command. He then ordered the ensign and the commissioning pennant hoisted; at that moment the ship went into commission, and the first entry in the ship’s deck log recorded this.
The commissioning pennant is the distinguishing mark of a commissioned Navy ship. A commissioning pennant is a long streamer in some version of the national colors of the Navy that flies it. The American pennant is blue at the hoist, bearing seven white stars; the rest of the pennant consists of single longitudinal stripes of red and white. The pennant is flown at all times as long as a ship is in commissioned status, except when a flag officer or civilian official is embarked and flies his personal flag in its place.
Narrow pennants of this kind go back several thousand years. They appear in ancient Egyptian art, and were flown from ships' mastheads and yardarms from, at least, the Middle Ages; they appear in medieval manuscript illustrations and Renaissance paintings. Professional national navies began to take form late in the 17th Century. All ships at that time were sailing ships, and it was often difficult to tell a naval ship from a merchantman at any distance. Navies began to adopt long, narrow pennants, to be flown by their ships at the mainmast head to distinguish themselves from merchant ships. This became standard naval practice.