Bob Denver revealed that the original plan was to have Gilligan's Island make sense

When The Professor made a working lie detector on season three of Gilligan's Island, we surrendered ourselves to the absurdity of the show. After all, the absurdity is kind of what makes Gilligan's Island a great show. Where would we be without the silly inventions, the dream sequences, the variety of visitors who are somehow able to leave while the castaways aren't? It gives the show its charm, and while we know that none of our core group will ever actually make it off of the island, that doesn't stop us from tuning in for more episodes.

In an interview with the Southern Illinoisan, Bob Denver explained that the original plan for Gilligan's Island was to provide viewers with a bit more logic to actually attempt to explain all of the strange things going on, on the island. 

He said, "Somewhere in the first year we were going to have a freighter sink off the island so we could go down and get all the stuff we needed and not make it up out of thin air."  

Instead, Denver said that the creators actually found it more entertaining to lean into the ridiculousness of the series and not offer up any sort of explanation at all. The actor said, "We all looked at each other and went, 'Nah, let 'em wonder!' It goes into fantasy at that point. You either buy it or you don't. No one ever asks how it was that I could fly until the Skipper pointed out that I couldn't."

Denver seemed to be aware that this was the core of what made Gilligan's Island so special, as while the audience might have been confused at times, they were still entertained.

Denver said, "We did 98 shows and they were all different. It was never boring. Even the crew had a good time. After the first month, they all said they were going to stay with the show. I asked one of them why and he said, 'Because when I go home at night I have something to tell my kids. Hey, we flew Gilligan into a wall today!"