Splashdown - S3-E22
Plot hole: Most of the episode focuses on just Gilligan and the Skipper riding the capsule out to sea (although the Howells and the girls attempt to stow away with them at first). However the whole plot changes at the end... suddenly with nobody aboard the capsule, Gilligan tells the Skipper it floated off and Skipper yells at him saying "We could have ALL been on that capsule!" when it suddenly explodes thus saving everybody as if the plot now called for everyone to have been on board. It was still supposed to be Gilligan and Skipper only.
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.