In the Royal Navy, the commissioning pennant has a cross of St George in the hoist and a white fly. Formerly, when the Royal Navy was divided into red, white and blue squadrons, there were four different pennants in use, the colour of the fly of three of the pennants corresponding with the colour of the squadron ensign, and a fourth for ships on independent commission (ie not attached to a squadron, therefore directly under the command of the Admiralty in London), with the fly containing (from top to bottom) red white and blue in a triband form (such ships would wear the red ensign). Modern commissioning pennants are significantly shorter than in previous centuries - typically 1m in length and only 10cm at the hoist, tapering to a squared-off point.
A boat carrying a captain of one of Her Majesty's ships will on ceremonial occasions fly a commissioning pennant from the bows of the boat as a symbol of his authority.
In the Hellenic Navy, the commissioning pennant (Greek Επισείων Πολεμικού Πλοίου, means Warship Pennant) blue coloured, has shape of isosceles triangle elongated, bearing a white cross near the base of the triangle. The flag has typically base to legth (height of triangle) 1 to 20. The cross has arms width 1/5 base legth and each arm length 3/5 of base length. The pennant flown on the top of mainmast (biggest mast).
It is said that the custom of wearing a pennant at the masthead of men-of-war stems from Tromp’s broom and Blake’s whip. In the 1650s the Dutch Admiral Van Tromp lashed a broom to his masthead as a sign that he had swept the British off the seas. In reply the British Admiral Blake hoisted a whip to the masthead to signify that he would whip the Dutchman into subjection. However, records show that pennants were in use well before this period as the mark of a warship.
In the days of chivalry, knights and their squires carried pennons and penoncels on their lances, just as men-of-war fly pennants from their masts. Records show that pennants were in use in the 13th century, when merchant ships were commandeered during war and placed in command of military officers, who transferred their trail pendants from their lances to the mastheads of the ships they commanded.
Today the pennant is hoisted on the day a warship or establishment commissions and is never struck until the day of decommissioning. It is, however, displaced by Royal Standards and the personal or distinguishing flags or pennants of commodores and admirals. In Navy ships the pennant is flown at the masthead, for which reason it is also commonly referred to as a masthead pennant.
It is the custom in many navies for a ship which is "paying off" to wear an extremely long commissioning pennant, which is normally at least the length of the ship, and the length of which reflects the length of service. This is in contrast to the modern practice of using pennants of not more than one or one-and-a-half metres for convenience.
It should be noted that formerly a ship "paid off" each time she returned home after a commission overseas: the term refers to the fact that sailors were not paid until the ship returned home, to avoid desertion. The bible of Royal Navy traditions and slang, Covey Crump, emphasises:
This custom is maintained in the United States Navy, where the paying-off pennant is known as the "homeward-bound pennant". Nevertheless, present usage in the Royal Navy has degenerated to using paying-off pennants only as part of a ship's decommissioning ceremony.