One type of stability is critical. What is the other type?

• A. Not critical
• B. Critical
• C. Dynamic
• D. Static

Answer: (A)

Stability here is described as a state relative to a threshold. When stability is labeled as critical, you’re at a dangerous limit where a disturbance could push the vessel toward instability. The other type in this simple pairing is not critical stability, meaning the ship has a safe margin and is not near that threshold. The remaining terms, dynamic and static, talk about different ways stability can be described—how the ship responds over time (dynamic) or its initial ability to resist heel (static)—but they don’t describe a binary critical versus noncritical condition. So the noncritical option best completes the pair with critical stability, indicating a safe margin.