Abstract: A weight block for a marine seismic cable comprises a heavy weight member with a soft, overlying layer. The weight block is bolted, hinged, or otherwise attached to the cable to provide desired ballast. The outer covering of the weight block is molded over the inner metal member with an injection molding machine or other standard techniques. The inner diameter of the molding on the block may have a plurality of ribs with a smaller diameter than the nominal diameter of the solid-filled or liquid filled cable.