(1)If a seaman employed in a United Kingdom ship combines with other seamen employed in that ship—
(a)to disobey lawful commands which are required to be obeyed at a time while the ship is at sea;
(b)to neglect any duty which is required to be discharged at such a time; or
(c)to impede, at such a time, the progress of a voyage or the navigation of the ship,
he shall be liable—
(i)on summary conviction, to a fine not exceeding the statutory maximum;
(ii)on conviction on indictment, to imprisonment for a term not exceeding two years or a fine or both.
(2)For the purposes of this section a ship shall be treated as being at sea at any time when it is not securely moored in a safe berth.