30. Every person subject to this Ordinance who, not being in command of any of the naval ships, naval vessels or naval establishments, fails when ordered to prepare for action by or against the enemy, or during any such action, to use his utmost exertions to carry the lawful orders of his superior officers into execution shall be liable, if the offence is committed with intent to assist the enemy, to suffer death, and in any other case, to suffer long imprisonment.