Navy Birthday 2024 is on Sunday, October 13, 2024: US Navy gear for birthday?

Sunday, October 13, 2024 is Navy Birthday 2024. 238th Navy Birthday Celebration 2013 in Annapolis, Maryland 238th Navy Birthday

Kind of short notice. There are a lot of places around Boston. Charleston Naval Shipyard for one. With a little more notice, you can have an American flag flown from the gaff of the USS Constitution in Boston harbor. The flag comes with a nice certificate, signed by the Commanding Officer, stating that the flag was flown in his honor. The significance of that is that the USS Constitution is the oldest US Navy warship, still in commission. You can still contact them, and ask that a flag be flown tomorrow, on the occasion of his birthday, and in recognition for his career of Naval service. It will take a while to get it, but to an old salt, it will be priceless.

Here's a link to the website:

What is the protocol for a dress for the Navy Birthday Ball?

Birthday Balls are formal events unless told otherwise. The dress you describe sounds fine as it is floor length, does have a slight clevage and a slit but nothing major. It shouldn't be a problem at all. If it looks good on you then that is enough.