Ship speed indicator and ship speed acquisition method

摘要

It is a ship's speed indicator that enables accurate measurement of the speed of water boat per water depth to a depth at which the speed of water boat sufficiently develops. According to a representative embodiment, the flow velocity at a plurality of different water depths up to a predetermined measurement range is measured in the fluid in which the vessel is floating, and the water depth held in advance for each water depth distribution And the theoretical curve of the speed of the water vessel relative to each other is adapted and the speed of the water vessel at an arbitrary water depth in a region deeper than the measurement range is calculated based on the adapted theoretical curve.