Abstract: A specially-equipped ship is configured for environmental cleanup to collect plastic waste floating in the ocean. A method of using the ship is described. The specially-equipped ship can retrieve floating plastic waste in the ocean, shred it, melt it, and cool it to form a solidified block that is usefully employed to form an artificial reef on the ocean floor to house aquatic biota. The ship is outfitted with a conveyor belt fixed to the ship; a furnace to make molten plastic; a davit to drop the solidified block into the ocean to form a reef on the ocean floor. Optionally the ship includes a mold to contain molten plastic; a shredder; a storage compartment to receive plastic particles from the shredder; a fish escape; a vertical wall; a boring machine; photovoltaic cells and/or windmills to produce electric energy.