18.—Bye-laws made under section 6 do not apply to craft operated in the course of duty of—

(a) the authority concerned,

(b) the Garda Síochána,

(c) the Defence Forces,

(d) the Revenue Commissioners,

(e) F10[Inland Fisheries Ireland],

(f) the Irish Coast Guard,

(g) the Commissioners of Irish Lights, or

(h) the Royal National Lifeboat Institution,

or any craft involved in bona fide law enforcement, emergency or rescue missions.