Here’s why the Union Jack is back
By: Mark D. Faram  
The resurgent “great power competition†at sea now officially trumps the Global War on Terror — at least on U.S. Navy ships.
Starting with morning colors on June 4, the Navy will return to flying the “Union Jack,†a small blue flag emblazoned with the stars of the 50 states — identical to the top left corner of the national ensign — from their jackstaffs, small flagpoles mounted on the bows of all Navy vessels when in port or at anchor.
Announced in NavAdmin message 039/19 and a Navy press release on Thursday, the policy change returns the “First Navy Jack†— and its “Don’t Tread on Me†rattlesnake slithering across thirteen red and white stripes — to its former role of signifying the oldest commissioned warship in the operational fleet.
https://www.navytimes.com/news/your-navy/2019/02/22/heres-why-the-union-jack-is-back-in-the-navy/