They're Off and Running - S1-E29
Other mistake: In several shots during the first turtle race, Gilligan is inexplicably wearing a wedding band (Bob Denver was married to his first wife at the time and forgot to remove it). (00:01:00 - 00:03:00)
Gilligan's Island (1964)
1 mistake in They're Off and Running
Starring: Alan Hale Jr., Jim Backus, Bob Denver, Natalie Schafer
More quotes from Gilligan's Island
Trivia: In the dream sequence, little Gilligan was played by Bob Denver's son Patrick.
Question: Why did the Howells, Ginger and Mary Ann have so many changes of clothes with them? It was only a three hour tour.
Answer: I've been binge watching it, and a couple of times trunks with costumes have washed ashore, and in one episode the professor figured out how to make thread for weaving cloth.
Answer: Bob Denver answered this when he was on a talk show hosted by Pat Sajak. He said they were going to write into an episode where the castaways found all these clothes, but it got too complicated, so he said, they decided, "who cares, it's only a TV show," and forgot about it. So the writers and actors even asked this, they just never bothered to address it.