To　improve　the　feasibility　of　system　identification　in　the　prediction　of　ship　manoeuvrability,　several　measures　are　presented　to　deal　with　the　parameter　identifiability　in　the　parametric　modeling　of　ship　manoeuvring　motion　based　on　system　identification.　Drift　of　nonlinear　hydrodynamic　coefficients　is　explained　from　the　point　of　view　of　regression　analysis.　To　diminish　the　multicollinearity　in　a　complicated　manoeuvring　model,　difference　method　and　additional　signal　method　are　employed　to　reconstruct　the　samples.　Moreover,　the　structure　of　manoeuvring　model　is　simplified　based　on　correlation　analysis.　Manoeuvring　simulation　is　performed　to　demonstrate　the　validity　of　the　measures　proposed.　©　2016　Weilin　Luo.