Complex sentence: Leeboards and centerboards, used to stabilize the junk and to improve its capability to sail upwind are documented from a 759 AD book by Li Chuan, an innovation adopted by Portuguese and Dutch ships around 1570.
Split into simpler sentences: Leeboards and centerboards, used to stabilize the junk and to improve its capability to sail upwind, are documented from a 759 AD book by Li Chuan. The innovation was adopted by Portuguese and Dutch ships around 1570.