Beauty Is as Beauty Does - S2-E2
Continuity mistake: We see a shot of the outside of Ginger's hut when she and the Skipper are first planning for the beauty contest. The door to the hut has a window in it and we can see the Skipper's hand leaning on the sill. We cut inside and suddenly Ginger is by the door and the window has vanished.
Beauty Is as Beauty Does - S2-E2
Continuity mistake: They used a standard electric phonograph. Later on, the phonograph is a bamboo and wood device with a ship's wheel as the turntable. It had to be cranked like the old Victrolas to work.
Continuity mistake: As Rodriguez goes back to Ginger, the Skipper straightens his hat. In the closer shot, Skipper straightens his hat again. (00:09:55)
Plot hole: Gilligan admits he put the Professor's measuring stick in deeper and deeper waters to catch bigger lobster. So wouldn't the Professor have noticed the stick has been moved further out (and more than once too) in the water rather than think the island is sinking? He always had all positions and locations down to a science in many episodes, so how could this have gotten past him?
Revealing mistake: As the Professor and Skipper get the test vehicle rocking faster, there are a few times that the metal poles built into the table legs to slide it is visible. Then as Gilligan slides on the table, the channels the poles slid along are visible, and it's obvious that the figure flying out into the men's arms is a dummy.
Castaways Pictures Presents - S2-E7
Plot hole: This movie was made so the castaways could be rescued, but how could they be found? The map the Skipper was pointing to didn't have anything on it that could realistically show where they exactly were, and all scenes in the film wouldn't help them get found at all, just made for good laughs.
Castaways Pictures Presents - S2-E7
Plot hole: During all their filming for their "silent" movie, the castaways are using talking in actual dialog to explain their overall situations on the island, but when played back at the end, it's just showing them all talking sped up without hearing voices being a silent picture. What was the point of them filming then with actual words? They may as well just moved their mouths randomly without actual words coming out. In addition, where did the "music" come from throughout the movie?
Castaways Pictures Presents - S2-E7
Continuity mistake: At the end of the filming, the Professor is drawing a line down the east coast of the United States on the board. When watching the film, the line is missing at the end.
Castaways Pictures Presents - S2-E7
Continuity mistake: After Mary Ann drops the basket, two pieces of fruit pop out of it. When Gilligan goes to pick it up, he picks up several pieces.
Castaways Pictures Presents - S2-E7
Continuity mistake: As Thurston calls cut, in the wide shot Gilligan stops and his spear dips with the tip down. In the closeup, Gilligan is now holding the spear straight up by his side.
Castaways Pictures Presents - S2-E7
Continuity mistake: The amount of rope around Mary Ann varies between shots.
Continuity mistake: The professor mentions he can't drink vodka with the Russians because he's allergic to alcohol, yet in the episode "Man with a Net" (with Lord Beesley), he drinks a strong alchoholic drink he made along with everyone else with no signs of any sickness, or reaction preventing him from drinking it.
Plot hole: This was obviously bad script writing, but let's figure out carefully how this failed rescue attempt (by Gilligan) doesn't really make sense. The two Russians were to be picked up at 11:00. When the castaways appear at the Russians' location, the Russians are gone. Gilligan states it's 8:00 according to his watch, due to the unaware fact he set his watch to Manila time (3 hours earlier). He claims to have set his watch when it was 10:30 in Manila - Skipper then yells there's 3 hrs difference between the island and Manila, so Gilligan sets his watch ahead 3 hrs and it's now 11:00. Here's the mistake: if it was 10:30 in Manila and there's a 3 hr. difference, it would have been 1:30 on the island, and also if Gilligan's watch stated it's 8:00 now (Manila time), he would have set it to 7:30 when hearing the 10:30 announcement on Manila radio (which he didn't do). Lots of these times just don't make sense.
Plot hole: Mr. Howell suggests the switching vodka for water idea, and then Gilligan empties one vodka bottle and puts water in it for the castaways. But there's no way this plan could have gone through since no castaway knew in advance how much vodka or how many bottles the Russians had to execute such a plan.
Continuity mistake: As Gilligan marches over the cliff, he's wearing Skipper's hat. As he's hanging on the branch, his regular white hat is on his head.
Continuity mistake: When Gilligan falls off of the cliff at the end, he is wearing different clothes and facing a different way than he was when he fell off.
Don't Bug the Mosquitoes - S2-E12
Other mistake: The 4 band members, all their equipment, months worth of food supplies, I am assuming medical supplies, change of clothes and other sundry items all magically fit into a small two seat helicopter.
Don't Bug the Mosquitoes - S2-E12
Character mistake: When the "Honey Bees" (Mary Ann, Ginger, Mrs. Howell) perform, Mrs. Howell (Natalie Schafer) messes up her lip-syncing throughout the number. But it is most noticeable at the very end when the girls put their heads together and say "buzzzzzzzzzzz" but Mrs. Howell is mouthing an "oooooooooo" which she changes to a "zzzzz" mid-way through the note.
Don't Bug the Mosquitoes - S2-E12
Continuity mistake: As Gilligan plays the drums, he shakes his head wildly, and the shades fly off. A moment later as they finish their song, Gilligan knocks over a drum, and it's up in the next shot.
You've Been Disconnected - S2-E17
Plot hole: Gilligan foils the rescue attempt by saying that before the storm, he wrapped up the telephone wires real good with the professor's rubber glue so they won't get wet... But the scene before this, all castaways were testing the phone when a storm instantly hit them without warning. Gilligan wouldn't have wrapped up the wires since there was no storm til the last second (in which they all ran and abandoned the wires).
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.