Theodore is the main protagonist of the series. He is one of the smaller tugs and wears a red baseball cap. He is a harbour tug, like his best friend, Hank.
He is one of the two harbour tugs along with Hank, moving barges and being pushers during ship docking operations. In the books by Michelle Mulder, Theodore is seen with another harbour tug named Lucy.
Theodore is kind, but he can have a tendency to be sometimes cheeky and fussy. He will help any tug in need. His goal is to be an ocean tug and to travel to other harbours across the world. But before that he must master the job of a harbour tug. He always tries to be friends with everyone who visits the Big Harbour.
Theodore is loosely based on a Turecamo Girls tugboat modified into a freelance design.
Theodore's whistle has been heard in many television shows and movies such as several episodes of Thomas the Tank Engine and Friends at Brendam Docks since the CGI switch and at the end of the Mayday episode, "Collision Course: Sinking of the Express Samina".
According to Andrew Cochran, to build Theodore Too, he was planning to modify a tugboat that looks like Theodore. It was to be used for marketing and promoting water safety. Eventually after all the hard research, none were close enough just to modify as Theodore. As a decision, Andrew Cochran has decided to build a Theodore from scratch design by model maker of the show Fred Allen.
In the Swedish version, Theodore is called Bosse.
Theodore is one of the few characters to appear in every episode, and have almost every episode revolving around him.
Ertl Company(changing face, bath toy, die-cast; all discontinued)