USCG Exam PracticeVessel stability — metacentric height, free surface
Under 46 CFR §28.501(c), which of the following changes to a vessel's lightweight characteristics is considered to adversely affect vessel stability?
- A. A shift of the longitudinal center of gravity of more than 2 percent of the vessel's length
- ✓ An increase in the vertical center of gravity at lightweight by more than 2 inches compared to the original lightweight valueCorrect
- C. An increase or decrease of lightweight displacement by more than 5 percent of the original lightweight displacement
- D. An increase in projected lateral area of more than 3 percent
Why B is correct
46 CFR §28.501(c)(1) specifies that an increase in the vertical center of gravity at lightweight by more than 2 inches (51 mm) compared to the original lightweight value adversely affects stability. The threshold for lightweight displacement change is 3 percent per §28.501(c)(2), and the longitudinal CG shift threshold is 1 percent of vessel length per §28.501(c)(3).
Cited:46 CFR §28.501