Estimating apparatus comprising a wind force characteristic estimating device, wherein the wind force characteristic estimating device comprises: a data output unit configured to output a plurality of parameter data (Dn) respectively including rotational speed data (R 1) indicating a rotational speed of a propeller of a ship, and wind velocity vector data (V WDn) indicating a wind velocity vector of wind force that may act on the ship; and an estimator configured to receive the plurality of parameter data (Dn) outputted from the data output unit, estimate first output values corresponding to the respective parameter data (Dn) to be log velocity vectors (V WTn) of the ship, and output the log velocity vectors (V WTn) as first output values to an image generating module configured to generate a wind force characteristic chart based on the first output values (V WTn), wherein the estimator has a memory including a plurality of cells, each cell is configured to store ground velocity vectors of the ship under one of a plurality of conditions defined by a combination of the rotational speed (R1, R2, R3,...) of the propeller of the ship and the wind velocity vector (X1, X2, X3,...) of the wind force against the ship for every one of the plurality of conditions, and wherein the estimator is configured to output, as the first output values being log velocity vectors (V WTn), average values of the ground velocity vectors stored in the cells specified by the condition corresponding to the combination of the rotational speed data (R 1) and the wind velocity vector data (V WDn) included in the received parameter data (Dn), wherein the rotational speed data (R 1) included in the plurality of parameter data (Dn) indicate the same rotational speed, and wherein the wind velocity vector data (V WDn) included in the plurality of parameter data (Dn) indicate different wind velocity vectors, and wherein each of the average values is calculated for the respective cell specified by the condition corresponding to the combination of the rotational speed data (R 1) and the wind velocity vector data (V WDn) included in the received parameter data (Dn) and outputted as the log velocity vector (V WTn) of the ship when the ship travels at the rotational speed indicated by the rotational speed data (R 1), wherein the estimator further includes an updating module configured to update the ground velocity vectors stored in the cells of the memory by using ground velocity vectors each calculated by a ground velocity calculating module at a timing at which the rotational speed data (R 1) and the wind velocity vector data (V WDn) inputted in the estimator are detected. a data output unit configured to output a plurality of parameter data (Dn) respectively including rotational speed data (R 1) indicating a rotational speed of a propeller of a ship, and wind velocity vector data (V WDn) indicating a wind velocity vector of wind force that may act on the ship; and an estimator configured to receive the plurality of parameter data (Dn) outputted from the data output unit, estimate first output values corresponding to the respective parameter data (Dn) to be log velocity vectors (V WTn) of the ship, and output the log velocity vectors (V WTn) as first output values to an image generating module configured to generate a wind force characteristic chart based on the first output values (V WTn), wherein the estimator has a memory including a plurality of cells, each cell is configured to store ground velocity vectors of the ship under one of a plurality of conditions defined by a combination of the rotational speed (R1, R2, R3,...) of the propeller of the ship and the wind velocity vector (X1, X2, X3,...) of the wind force against the ship for every one of the plurality of conditions, and wherein the estimator is configured to output, as the first output values being log velocity vectors (V WTn), average values of the ground velocity vectors stored in the cells specified by the condition corresponding to the combination of the rotational speed data (R 1) and the wind velocity vector data (V WDn) included in the received parameter data (Dn), wherein the rotational speed data (R 1) included in the plurality of parameter data (Dn) indicate the same rotational speed, and wherein the wind velocity vector data (V WDn) included in the plurality of parameter data (Dn) indicate different wind velocity vectors, and wherein each of the average values is calculated for the respective cell specified by the condition corresponding to the combination of the rotational speed data (R 1) and the wind velocity vector data (V WDn) included in the received parameter data (Dn) and outputted as the log velocity vector (V WTn) of the ship when the ship travels at the rotational speed indicated by the rotational speed data (R 1), wherein the estimator further includes an updating module configured to update the ground velocity vectors stored in the cells of the memory by using ground velocity vectors each calculated by a ground velocity calculating module at a timing at which the rotational speed data (R 1) and the wind velocity vector data (V WDn) inputted in the estimator are detected.