USCG Exam PracticeVessel stability — metacentric height, free surface
Under 46 CFR §28.540, when a vessel's tanks are fitted with cross-connection piping, how must the free surface effect be calculated unless isolation valves are installed and kept closed?
- A. Each tank is calculated individually using the inertia method
- B. Only the tank with the greatest free surface effect is used
- ✓ The tanks must be assumed to be one common tankCorrect
- D. Free surface effect is disregarded for cross-connected tanks
Why C is correct
46 CFR §28.540(b) requires that the free surface effect of tanks fitted with cross-connection piping be calculated assuming the tanks are one common tank, unless valves that will be kept closed to prevent liquid transfer as the vessel heels are installed in the piping.
Cited:46 CFR §28.540