Who is Grandfather/Captain Ludlow from Legends of the Fall and what is their importance?

Ludlow's father, Grandfather/Captain Ludlow, is a sea captain, who spends most of his life at sea. He hates that Ludlow bought him a boat and sends money to repay him little by little. Captain Ludlow teaches Tristan everything he knows about sailing, and he later gives Tristan the schooner.