In this talk, we present a method for estimating the range of a distant ship in shallow water using a vertical array and a guide ship at a known range close to the array. The method involves a combination of four well-known approaches: (1) blind deconvolution; (2) waveguide invariant; (3) virtual receiver; and (4) array invariant. The main idea is to transform theoriginal task of estimating the range of a distant ship using a vertical array into estimating the range with a synthesized horizontal array aroundthe guide source exploiting the waveguide invariant theory. The proposed method is demonstrated for a surface ship radiating broadband noise (100–500 Hz) at 10 km range, using a 56.25-m long vertical array in approximately 100-m water and the same ship at 2 km range as the guide ship.