is constructed so as to have an open end 26 of inlet conduit 16 exposed to the cool subsurface water 28 the open end 20 of outlet conduit 18 is supported at surface 22 by a float 30 the open end 26 of inlet conduit 16 is held down by weight 32 the submarine 10 is modified not only to include water pump 12 but includes hatches 34 and 36 and hatch covers 38 and 40 inlet conduit 16 and outlet conduit 18 are preferably fabricated from large diameter hoses that can be flattened and wound up on reels 42 so that hatches 34 and 36 can be closed when submarine 10 is underway when pump 12 is operated the subsurface cold water 28 is pumped to the water surface 22 thereby cooling the water at the water surface 22 such that if the onset of tropical cyclonic activity is detected sufficiently early the cooling of the surface water may be sufficient to inhibit or at least weaken the development of a tropical cyclone the water pump 12 included in the submarine 10 may also be provided with a heat pump or refrigeration unit for further cooling of the cold water inletted via conduit 16 and outletted via conduit 18 the heat generated by the operation of the water pump 12 or extracted by the operation of a heat pump when included can be used within the submarine or can be vented to the water below the submarine.