Actually, that black boat poses no significance to anything at all.
"Prime Pier is across from Mode Street. Occasionally docked at Prime Pier is the Plasma Ship, a black boat that Team Plasma uses to get to Liberty Garden. A few of the local citizens have noticed the strange black boat and have become concerned." - Bulbapedia
It was just a background boat that Team Plasma used to go to Liberty Garden.
The Liberty Garden boat is yellow and to the far leftest pier.
The cruise ship is orangy-yellow and to the far rightest pier and is available only after the player defeats the Elite Four, and from the times corresponding to the current season in the game:
- Winter: 4:00-6:59pm
- Spring: 5:00-7:59pm
- Summer: 7:00-9:59pm
- Autumn: 5:00-7:59pm
Basically, you literally cannot do anything with the black boat, at all. It is just background in the game.
- 12.14.2011 11:44am