It is wise to untie the ships when the water rises.
No, no... that's wrong. They say the land is sinking... so put more ships there, and tie them all tightly to the pylons. That way, they'll hold the land up and keep it from sinking.
Of course if the ships have to go out to sea (perhaps to another country for a gay pride celebration or something important like that) you'll have to tie the land to something else to hold it up til the ships come back.