Who is Wellard from Lieutenant Hornblower and what is their importance?

Wellard sets sail on the Renown as a volunteer. He is described as being a slight young man, around fifteen years of age, in addition to having a rather obnoxious, high-pitched voice. Disliked by Sawyer, the ship's commander, Wellard is regularly beaten and thrown below deck. It is believed that Wellard at some point pushed Sawyer down the stairs, causing the injuries that led him to give up command of the ship. After the "accident", Hornblower takes Wellard under his wing. Wellard later drowns in an accident.