roll restoring coefficients of planing boats’ maneuver using 2d + t approach

Importance of maneuverability as a main feature of safety for a marine craft is broadly recognized. mathematical modeling together with maneuver hydrodynamic coefficients (mhcs) is employed for maneuverability simulation. generally, experimental, analytical and numerical methods are employed for extraction of mhcs which 2d+t approach is recently employed. in this study, roll restoring mhcs of planing hulls are evaluated by the 2d+t approach. running attitude of planing boats alters during any kind of maneuver due to forward speed change. this study presents a simple and applicable pmm procedure for consideration of running attitude to extract mhcs. in this procedure at a given forward speed, the planing hull is restrained to pmm apparatus in a fixed running attitude resulted from conventional resistance test at the same forward speed. this procedure is employed by 2d+t method for prismatic planing hulls in a set of forward speeds in roll condition. it has resulted three regression formulae for y_ϕ, k_ϕ and n_ϕ as function of dead-rise angle and froude number. the result of this study can be directly used in simulation of maneuvers via mathematical model. moreover, this approach may be followed for other mhcs related to sway and yaw motions in future work.