if (document.images) {
  img01 = new Image();
  img01b = new Image();
  img01.src = "images/yacht_01.gif";
  img01b.src = "images/yacht2_01.gif";
  
  img02 = new Image();
  img02b = new Image();
  img02.src = "images/yacht_02.gif";
  img02b.src = "images/yacht2_02.gif";
  
  img03 = new Image();
  img03b = new Image();
  img03.src = "images/yacht_03.gif";
  img03b.src = "images/yacht2_03.gif";  
  
  img04 = new Image();
  img04b = new Image();
  img04.src = "images/yacht_04.gif";
  img04b.src = "images/yacht2_04.gif";   
  
  img05 = new Image();
  img05b = new Image();
  img05.src = "images/yacht_05.gif";
  img05b.src = "images/yacht2_05.gif";   
  
  img06 = new Image();
  img06b = new Image();
  img06.src = "images/yacht_06.gif";
  img06b.src = "images/yacht2_06.gif";   

}
function on(name) {
	if (document.images) {
		fullname = eval(name + "b");
		document[name].src = fullname.src;
	}
}
function off(name) {
  if (document.images) {
    fullname = eval(name);
	if (fullname.complete) {
      document[name].src = fullname.src;
	}
  }
}