A movie about a child that gets kidnapped and held captive on a boat?

Ok. so i'm recollecting this from a long time ago, so i think the child gets kidnapped from his/her school by a guy with a fake mask on and something happens to the mom or whoever, i think he was disguised as the principal, anyway he takes him/her onto a boat and he/she is held captive in a small room below deck and some time goes on and he/she uses some battery or something to set the stove on fire while making the kidnappers tea, while he trys to put the fire out she trys to swim to shore where a man is fishing he sees her and then the kidnapper shoots the fisherman and ends up getting her back on the boat,... thats all i remember can someone tell me what movie it is? I'm dieing to see it!!