Question 52 RVR04 - Master or Mate of LT 200 GRT

The Correct Answer is A ### Why Option A is Correct **A) Add weight in the center line lower holds or double bottoms** The problem states that the list occurred because the center of gravity ($G$) rose above the transverse metacenter ($M$), meaning the vessel has developed negative or insufficient stability (negative or dangerously small $GM$). The most prudent action to restore stability is to **lower the vessel's center of gravity ($G$)**. Adding weight (usually ballast or dense cargo) into the lowest available spaces, such as the double bottoms or low centerline holds: 1. **Lowers KG:** Decreasing the vertical height of the vessel's center of gravity. 2. **Increases GM:** Since $GM = KM - KG$, lowering $KG$ increases the Metacentric Height ($GM$). A positive and sufficient $GM$ restores stability, corrects the list, and prevents the vessel from remaining "tender" or capsizing. 3. **Reduces Free Surface Effects:** Adding weight in tanks that can be pressed up (completely filled) minimizes free surface effects, which is crucial for recovering stability. ### Why Other Options Are Incorrect **B) Shift weight to the centerline** While shifting weight inward (to the centerline) eliminates the angle of heel (the list itself), it does not change the vertical position of the center of gravity ($KG$) significantly. Therefore, it does not fix the underlying stability problem (the insufficient $GM$). The vessel would remain highly unstable, or "tender," even if momentarily upright. **C) Remove weight from the lower holds or double bottoms** Removing weight from the lower parts of the vessel causes the vessel's center of gravity ($G$) to rise. Since the original problem was that $G$ was already too high, this action would dramatically reduce $GM$, making the vessel even more unstable and potentially leading to capsizing. This is the opposite of the required corrective action. **D) Shift weight to the high side** Shifting weight horizontally to the high side is an action intended to counter the existing moment and reduce the angle of heel. However, like Option B, it only addresses the symptom (the list) without fixing the root cause (insufficient stability/low $GM$). Furthermore, shifting weight horizontally may introduce or exacerbate free surface effects if liquid is involved, potentially worsening stability.