Desertion and absence without leave

No person employed or engaged in any capacity on board a mechanically propelled vessel shall— (a) neglect or refuse, without reasonable cause, to join his mechanically propelled vessel or to proceed on any voyage in his vessel; (b) cause to be absent from his vessel or from his duty at any time without leave and without sufficient cause; (c) desert from his mechanically propelled vessel; (d) fail to act or behave with discipline befitting his duty and mandate.