I'm just guessing it's WW2 because it was purchased from the estate of a WW2 vet. It's 3 3/4" in diameter. The camera flash throws off the color somewhat. It isn't that bright and vibrant looking in person. Anybody?
Boat (yacht) club burgee... And probably not a US one, which especially in older designs are almost always a combination of red white and blue (along with whatever pattern and such).
Thanks for the ID. I guess i'll have to check out the shoulder boards I have too then. They may not be military either, could be part of his yacht club attire. This guy was into alot of different things from the Lions Club president to building soap box derby racers, as well as old wooden boat refurbishing. At least I know the cracker jack wool navy pants and hats are authentic.