How to measure water depth

1, in the known point on the set ranging goniometer device, determine the orientation of the target ship and the horizontal distance to the ship, to determine the plane position of the ship, the bathymetric rod, bathymetry installed in the bow of the ship, the staff in the bow Division ruler, and will be measured by the depth of water through the walkie-talkie to the shore to measure the staff, the observer for the measured static depth of the difference between the topographic point of the elevation, and then draw the isobath to get the underwater topographic maps