An action against a boat or vessel may be instituted by the filing in the district court of the county where it may be of a complaint against it by name, or, if it have no name, by description, verified by the plaintiff or some person having knowledge of the facts, and setting forth the demand, and on whose account it accrued. Thereupon the court administrator shall issue a warrant, returnable in 20 days, directing the sheriff to seize such boat or vessel and detain it in custody, with its tackle, apparel, and furniture, until discharged by due course of law. Such warrant shall be served and returned as in the case of a writ of attachment. Upon the return of the warrant, proceedings shall be had against the boat or vessel seized in the same manner as if the action had been instituted against the person on whose account the demand accrued. The master, owner, agent, or consignee of the boat or vessel may appear on its behalf and answer the complaint. For sufficient cause shown, the answerer shall be entitled to a continuance, but such continuance shall not operate as a discharge of the boat or vessel from custody, and no continuance shall be granted to the plaintiff.