Hugh "Seafoam" McDuck is ancestor of Scrooge McDuck, who appears in Down & Out in Duckburg.
Seafoam first appeared in September 1953, in the story, "The Horseradish Story", he signed a contract with Swindle McSue, in the contract without reading it, itt turned out Swindle would come in possession of all of Seafoam's riches if he failed to meet his end of the contract (delivering a crate of horseradish to Jamaica). Of course, Swindle sabotaged Seafoam's boat, the Golden Goose, which soon sunk.
The impoverished Seafoam, desperate to make his fortune back, turned to piracy in the Caribbean, though he was hardly the most cruel of buccanneers. Becoming quite famous in his profession, Captain Seafoam acquired a decent stash of loot, which his descendant Scrooge McDuck (time-traveling) helped him save from his rival Captain Walrus. In thanks, after burying the treasure, Seafoam willed it to his 21st-century descendant, whoever might be.
He was featured in Don Rosa's The Life and Times of Scrooge McDuck, where Scrooge inherits his golden teeth and the McDuck watch.
In television he makes appearances in both Ducktales 1987, and Ducktales 2017.