function displaySpeed(speed)
{
   if(!speed)
      speed = $('#post').val();
   
   if(speed == 'Chief Engineer' || speed == 'Second Engineer' || speed == 'Third Engineer' || speed == 'Fourth Engineer')
      $('#speed').attr('disabled', false);
   else
   {
      $('#speed').attr('disabled', true);
      $('#speed').val('');
   }
   
   date_of_birth = $('#date_of_birth').val();
   if(date_of_birth == 'ΔΔ.ΜΜ.ΓΓΓΓ')
      $('#date_of_birth').val('');
}

function displayPost(post)
{
   if(post)
   {
     if(post == 'Other')
        $('#post_other').attr('disabled', false);
     else
     {
        $('#post_other').attr('disabled', true);
        $('#post_other').val('');
     }
   }
}