Quick Before It Sinks

Synopsis
The Professor has been using a measuring stick in the Lagoon and feels that the Island is Sinking! Can the castaways build a ark/raft before its too late?

Trivia

 * One of the more sillier funny episodes - such as Mr. Howell actually having to do physical labor; when Gilligan and the Skipper test out the hut/raft before it collapses; when Gilligan reveals that was he who had changed the stick in the water for his lobster traps
 * In Rescue from Gillgan's Island, the castaways do make a hut/raft to escape the Island.