USS Indianapolis sailors display the flag of the president of the United States. - Wikimedia Commons/U.S. Navy photo NH 68040, Naval History & Heritage Command, cropped and resized, Public Domain.Flags flown on vessels have been a nautical tradition for centuries. They've allowed pirates to project fear, and enabled naval vessels and civilians alike to identify themselves. The United States' formidable Navy, of course, is no exception to this rule, and its ships will frequently boast the beloved Stars and Stripes. However, there are other important U.S. military traditions that help to vary the flags that its vessels display, such as mascots and emblems.U.S. Navy ships are typically named for servicepeople or high-ranking officials, as is the case with the service's formidable USS Gerald R. Ford – the world's largest aircraft carrier. Along with this often comes an emblem that emphasizes the connection. These symbols evoke crew pride and togetherness, while also serving as an important identifier. They can take the form of different animals or other symbols, and there are some iconic ones in the U.S. Navy in particular that make for excellent flags. From a legendary pirate symbol to a furious grizzly bear, here are some of the coolest ones that have been sported by U.S. naval vessels besides the Star-Spangled Banner itself.Read more: 10 Of The Largest Navies In The World, Ranked By Self-Reported Total Naval Assets1. The grizzly bear flag of USS Harvey C. Barnum JrUSS Harvey C. Barnum Jr viewed from the dock. - U.S. Navy photo by Mass Communication Specialist Seaman Apprentice Jackson C. Rott, resized and cropped, Public Domain.As noted, with the likes of the USS Gerald Ford and the USS Abraham Lincoln, there have been a lot of U.S. Navy ships named after American presidents. It's not simply about those who have held the highest office in the land, though. Take the USS Harvey C. Barnum Jr., for instance, a guided missile destroyer of the Arleigh Burke class and one of the more recent additions to the Navy's arsenal of ships. Its now-retired namesake Colonel Harvey C. Barnum Jr. was a member of the Marine Corps and is a proud Medal of Honor recipient.The ship's battle flag, Task & Purpose notes, is also designed as a tribute to the colonel, featuring a formidable grizzly bear. It's an intimidating and imposing sight in its own right, of course, but it serves a secondary function: Those with whom the colonel served knew him well for his words of wisdom, including the pithy "If you're going to be a bear, be a grizzly." Sailors who will serve on the vessel, of course, will surely be inspired to do so boldly, fiercely, and uncompromisingly, like the grizzlies that the former colonel wants them to be. There are few more intimidating flags on the seas than this one, that's for certain.As for the ship itself, it's designed to take on a broader combat role, allowing it to combat a range of nautical threats from above and below the waves, and is set to be c