🔍 Key Concepts

• Tonnage openings in deck structures and how they’re treated under tonnage measurement rules • The difference between temporary/removable closures and permanent structural material • What type of closure the regulations consider acceptable for tonnage purposes (material and strength)

💭 Think About

• Ask yourself: Is a tonnage opening something that can be lightly covered, or does it need a closure comparable in strength to the surrounding deck? • Which option sounds like a proper structural closure rather than a light or makeshift cover? • Think about what surveyors expect when measuring gross tonnage—would they count an opening as closed if it were only covered with a weak or non‑structural material?

✅ Before You Answer

• Compare each choice and decide which provides a strong, durable, and watertight closure similar to the deck itself. • Eliminate any options that sound like temporary, non‑structural coverings. • Remember that for tonnage, authorities look for closures that are substantial enough to be considered part of the ship’s structure, not just something laid over an opening.