If the master of such vessel cannot be found, or if he neglect or refuse to remove the same, as required by the said notice, the harbour master may remove such vessel to such station as he shall select, and the expences of such removal shall be paid to the undertakers by the owner of the said vessel or the master thereof: Provided always, that previous to the repair of harbour, dock, or pier, which shall require the removal of the vessels therefrom, the harbour master shall give three days notice of such repair and of the necessity for such removal to the collector and comptroller of the Customs of the district within which the harbour, dock, or pier is situate, or which shall be specified for that purpose in the special Act, and cause a like notice to be affixed on some conspicuous part of such custom house and of the office of the undertakers.