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.