To detachably position a jelly fish removing tool to an intake provided on the portside of a tanker.

A square water flow generating pipe 10 is suspended from a deck Se by two suspending ropes 31 and positioned vertically and longitudinally. The water flow generating pipe 10 is positioned laterally and longitudinally by two guide ropes 52 each provided with a weight 53 attached to a leading end (lower end) 52a while guiding its raising and lowering operation. The pipe 10 has a number of blowout holes to blow water fed to the pipe 10 through a feed hose 21 connected to a pump (hydrant) B on the deck Se into the sea therethrough, so that the water flow prevents a jelly fish K from approaching to the intake A.