Abstract: To determine the erodability of soil, in particular soil belonging to the underwater floor, a vertically displaceable spray nozzle is installed above the floor to produce a water flow onto or over the floor soil. The water flow forms a pit in the soil by erosion. The spray nozzle is systematically lowered by means of displacement means in a manner such that the nozzle follows the descending pit floor. The speed at which the spray nozzle follows the pit floor is determined and the erodability is derived at various depths from the relationship between this speed and the flow rate of the water flow. To obtain an accurate and reproduceable determination of the erodability a quantity, which is a function of the distance between the bottom end of the spray nozzle and the floor of the pit, is measured with a sensor fitted to the spray nozzle.

Abstract: For burying conduits in the bottom of a waterbed the invention proposes to provide protruding parts such as fins on or in the proximity of the conduit, which cause disturbances in the flow of water near the conduit to erode the bottom of the waterbed in such a way that the conduit will be buried.