FAQ

I just saw an episode where they were on Devil's Island in convict gear, but before the transfer, their clothes changed back to their original appearance. Why should their clothes changed from whatever they wore in the episode back to what was wore when they started time-travelling?

Presumably they "reset" back to the way they were upon entering the time stream, although this would also mean they wouldn't remember what happened to them in previous episodes. However, the real reason is likely for continuity's sake, as it's easier to have them wear the same clothes every week.

He went to rescue Tony in 1912 and to get the Captain of the Titanic to devert the ship from the iceberg. The Captain threw the newspaper showing the Titanic disaster out of a porthole. Doug along with Tony were saved before the Titanic sank and Doug wore his 1912 suit for the rest of the series.

The final episode, "Town of Terror", ends with Tony and Doug transferring out, and then it shows a montage of clips from the first episode, "Rendezvous with Yesterday", in which Tony and Doug are dropped onto the Titanic. Some viewers wonder if this was intended to mean that they are hopelessly trapped in an endless loop of 30 adventures.

The actual reason is much more mundane. After "Town of Terror" was initially broadcast, the show went into repeats for the summer, and the first of those was "Rendezvous with Yesterday". The montage was merely a teaser for the following week's repeat episode.