A synthetic aperture radar is crucial for detecting ships. In this study, to improve the detection capability of weakly scattering targets and reduce false alarms, a detector <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$F_{vh}$ </tex-math></inline-formula> based on the scattering characteristics of ships is proposed after an in-depth study of the differences between ship and sea surface scattering mechanisms. The volume scattering mechanism and the helix scattering mechanism are fused, and the volume scattering power is used to describe the scattering structure on the ship, and the helix scattering power is used to increase the difference between the ship and the sea surface. We test on 4 GF-3 fully polarized synthetic aperture radar data. The experimental results show that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$F_{vh}$ </tex-math></inline-formula> has improved detection capability and can successfully minimize false alarm generation.