Lu Wi
In Lu Zhen's tent, the five captains sat at a rectangular table, while he sat at the end of the table.
Lu Zhen quickly explained how the boat works and gave them some rough drawings of the blueprint of the board and explained to them how they worked.
All the five captains' eyes widened, almost like an enlightenment, the more they heard him. Finally, when he completely explained everything, they revealed a bitter expression.
As people with high status, every captain was naturally educated when young, so they quickly understood the concept of it. Actually, it was nothing new and could be said to be simple as well.
But they never thought of using it because they didn't need it most of the time.