🔍 Key Concepts

• Lightening hole: a large opening cut in a structural member (like a floor or web) to reduce weight while still keeping strength • Difference between lightening holes and limber holes: limber holes are usually smaller and low down for drainage • Carefully compare what the letters A, H, and J are actually pointing to in the illustration GS-0086

💭 Think About

• Look closely at the bottom structure: which letters point directly to the large oval cutouts in the floors, and which point to other parts such as plating or stiffeners? • Ask yourself: is each choice (A, H, J) pointing to the same type of feature, or are they marking different structural elements? • Consider why the exam offers the option "all of the above"—do all three letters really identify lightening holes, or are some clearly identifying something else?

✅ Before You Answer

• Verify which labeled items are openings in a structural member rather than the member itself (like plating, frames, or longitudinals). • Confirm that a lightening hole is not a drainage-only opening near the turn of the bilge (that would be a limber hole). • Before choosing "all of the above," make sure every listed letter actually points to the same kind of opening (lightening hole) in the drawing.