Shi Potian is the best known ocean leaper in Jin Yong universe.
Of course, what he really did was leap off a boat and land on a piece of wooden flank that he threw across the water.
But since we're talking about jumping across the ocean, I just want people to know, that Rong Cai from "Sword Stained With Royal Blood" also performed a qualifying ocean leap:
双足一顿,提气向岸上跃去 ... 荣彩下落时见足底茫茫一片水光,正自惊惶,突见船板飞到,恰好落在脚下水面之上,当真大喜过望,左脚在船板 上一借力。跃上了岸
Not only did Rong Cai land on the wooden flank, he used it as the middle station for a longer leap to the land.
Rong Cai is the answer to jumping across the ocean during the final Ming era.