What is the main advantage of a double-hull tanker structure?

The primary advantage of a double-hull tanker structure is the prevention of oil spills during emergencies. Double-hull tankers are designed with two layers of hull that provide an additional barrier against leakage. In the event of a collision, grounding, or other accident, the outer hull can absorb the impact and protect the inner hull that contains the cargo. This design significantly reduces the risk of cargo spilling into the surrounding environment, thereby minimizing the potential for ecological damage and contributing to safer transportation of oil and hazardous materials.

The other options do not capture the core reason for implementing a double-hull design. Improved aerodynamics is not a key feature of tanker design, as these vessels primarily focus on cargo carrying rather than aerodynamic efficiency. Additionally, while some double-hull tankers may have slightly better cargo efficiency, they are not explicitly designed for increased cargo capacity. Finally, reduced construction costs are not a characteristic advantage, as double-hull tankers typically involve higher construction expenses due to their more complex design and the materials required, compared to single-hull tankers.