Any person may make application to any board of local inspectors for a certificate of service as able seaman, and upon proof being made to said board by affidavit and examination, under rules approved by the Secretary of Commerce, showing the nationality and age of the applicant and the vessel or vessels on which he has had service and that he is entitled to such certificate under the provisions of this section, the board of local inspectors shall issue to said applicant a certificate of service, which shall be retained by him and be accepted as prima facie evidence of his rating as an able seaman. Each board of local inspectors shall keep a complete record of all certificates of service issued by them and to whom issued and shall keep on file the affidavits upon which said certificates are issued. The collector of customs may, upon his own motion, and shall, upon the sworn information of any reputable citizen of the United States setting forth that this section is not being complied with cause a muster of the crew of any vessel to be made to determine the fact; and no clearance shall be given to any vessel failing to comply with the provisions of this section: _Provided_, That the collector of customs shall not be required to cause such muster of the crew to be made unless said sworn information has been filed with him for at least six hours before the vessel departs, or is scheduled to depart: _Provided further_, That any person that shall knowingly make a false affidavit for such purpose shall be deemed guilty of perjury and upon conviction thereof shall be punished by a fine not exceeding $500 or by imprisonment not exceeding one year, or by both such fine and imprisonment, within the discretion of the court. Any violation of any provision of this section by the owner, master, or officer in charge of the vessel shall subject the owner of such vessel to a penalty of not less than $100 and not more than $500: _And provided further_, That the Secretary of Commerce shall make such rules and regulations as may be necessary to carry out the provisions of this section, and nothing herein shall be held or construed to prevent the Board of Supervising Inspectors, with the approval of the Secretary of Commerce, from making rules and regulations authorized by law as to vessels excluded from the operation of this section. (Mar. 4, 1915; sec. 13.) (Effective on American vessels beginning Nov. 4, 1915; on vessels of foreign nations not covered by treaties Mar. 4, 1916; on vessels of other foreign nations after termination of treaties.) Undermanning.