Section 2
SEC. 2. The income derived exclusively by non-resident citizens of the United States or by corporations organized under the laws of the United States of any of its political subdivisions from the operation of ships documented under the laws of the United States, except income derived by such citizens or corporations from the operation of a ship or ships in the Philippine coastwise trade, shall not be included in the computation of the residence tax collectible under Commonwealth Act Numbered four hundred and sixty-five, entitled "An Act to impose a Residence Tax."