The correct answer is C) Lowering a weight suspended by a boom onto the deck. This is because lowering a weight onto the deck does not negatively impact the stability of the vessel. In fact, adding weight to the deck can actually improve a vessel's stability by lowering its center of gravity. The other answer choices would decrease the vessel's stability - A) Running with a following sea can make the vessel more susceptible to rolling, B) Topside icing increases the vessel's top-heaviness, and D) Using fuel from the tank reduces the overall weight of the vessel, raising its center of gravity.