Question 40 OSE02 - Assistant Engineer - OSV

The Correct Answer is B **Explanation for Option B (Correct):** Option B is correct because of the fundamental purpose and design of a marine keel cooler. A keel cooler is a type of heat exchanger used to cool the engine's closed-loop freshwater system by transferring heat directly to the surrounding seawater. To achieve effective heat transfer, the cooling element (the tubes or plates containing the hot freshwater) **must be in direct contact with the seawater** and fully submerged. Therefore, a keel cooler is always mounted on the **outside of the hull below the water line**. **Explanation for Other Options (Incorrect):** * **A) The keel cooler is mounted on the inside of the hull below the water line.** This is incorrect. If the cooler were mounted inside the hull, it would only be in contact with the structure of the ship, not the surrounding seawater, rendering it useless for cooling the engine water. * **C) The keel cooler is mounted on the outside of the hull above the water line.** This is incorrect. Mounting the cooler above the water line would expose it to air, which is a poor medium for transferring heat away from the engine water compared to seawater, especially since the cooler relies on being submerged for its operation. * **D) The keel cooler is mounted on the inside of the hull above the water line.** This is incorrect for the same reasons as A and C. It would neither be in contact with seawater nor below the water line, making heat transfer ineffective.