I was checking the Port Everglades webcam to see which cruise ships were in port today just as a US Navy submarine was leaving the port. According to the audio chatter, the port was closed while she was leaving port. I grabbed a couple of screen captures of her which you can see below. She looks like a Virginia class attack submarine. The shape of her sail and the markings on it match photos I found online of Virginia class subs.
Port Fever posted a couple videos of the sub on YouTube. The first shows several people leaving the sub followed by their gear. The second video is of the sub leaving port.
My screen shots (click for a slideshow):