The most inexpensive Sea unit, Black Boats are unique in that they can repair other units.
Unlike any other unit, Black Boats are capable of Repairing units of the same army. To do this, the Black Boat must be adjacent to any allied unit. When this is done, one can select the "Repair" command, and select the unit they wish to repair. Once processed, the Black Boat will repair the target unit for 1 HP, also refilling its Fuel and Ammo in the process. These repairs will cost the army involved 10% of the unit in question's deployment cost. Instructing a Black Boat to repair a full HP unit will not cost anything, but will still refill it's Fuel and Ammo. Units being repaired by Black Boats may still take their turn as normal, so one can repair a unit before engaging in combat, where applicable.
Additionally, Black Boats are capable of transporting and protecting up to two Infantry or Mech units. As with all other transports, if the Black Boat is destroyed, any units being transported will be destroyed as well. To be loaded, the Black Boat must be on either a Port or Shoals tile.
Being able to traverse shoals, Black Boats can also block Land units from crossing connecting Shoals tiles. Despite being relatively inexpensive, Black Boats are quite sturdy units, taking little damage from most Direct Combat attackers. They still take moderately high damage from Indirect Combat, however, so don't expect them to last too long against them.
As with most Transport units, Black Boats are defenseless on their own, and are rarely worth the effort to sink unless they are no other targets nearby. It is recommended to avoid combat adjacent to any bodies of water where enemy Black Boats are, as they can repair hostile units and turn the tables of a land battle if combat continues in that area. Due to their low Fuel supply and high movement, Black Boats tend to run out of Fuel rather quickly if they are constantly moving, so keeping them on the move can lower their time spent repairing enemies.