Don’t remove get_header().
Duplicate the header.php to header-{custom-name}.php, let’s say (header-nonavfooter.php) then in the template file replace get_header() with get_header('nonavfooter').
In the new header file (header-nonavfooter.php) remove the code related to navigation.
Do the same for the footer.php also(Create a new footer.php and remove the footer parts that you don’t need), remember not to remove wp_footer() available in footer.php.