Pirates of the Visutula

[Targan]

Steel-hulled tugs have a lot of mass below the waterline. I'm wildly speculating but I reckon you could easily have 10% of a tug's mass added to the upper superstructure without causing instability. In addition, the Wisla Krolowa is operating on a river, not the open ocean, so there's not much in the way of swell to have to deal with.