For you, what was the appeal of this series?  
		 
		
	 
The Last Ship is a mix of 
Star Trek's ship-based adventure and exploration, 
Contagion's globe-spanning story and pandemic themes, the post-apocalyptic setting of zombie stories, a dash of 
The West Wing's (mostly) sunny picture of Americans and the American Way, the popcorn action movie thrills and logic of the 
Mission: Impossible movies, and the military triumphalism of Michael Bay movies (he's an executive producer), minus his noxious stereotypes. 
Each season tells a distinct story in a different part of the world, the action is exciting and varied, the writing is generally strong (and particularly shines in developing minor characters, far more than 
Voyager or 
Enterprise ever did), and the cast is first-rate. It's emotionally gripping and entertaining as hell. As I said, the latter two seasons, while worthwhile for completists, aren't as strong, and the finale was a bit of a weird dud. But, the first three seasons are great.
	
		
	
	
		
		
			Seaquest is the only ocean based sci fi show I know of.  Are there other water-based Sci Fi shows?
		
		
	 
While not containing any outright fantasy elements (i.e., no aliens or zombies or anything), the first two seasons of 
The Last Ship heavily focus on developing a cure/vaccine for a lethal virus (science), and, though the answers aren't found in a five-minute stretch like they are on, say, a 
Voyager episode, the speed and efficiency with which the scientists accomplish their discoveries isn't exactly realistic (fiction). So, it's sort of sci-fi in the way the 
Mission: Impossible movies and their outlandish gadgets are.