The stability cost of a taller carrier hangar

What stability cost comes with a 20-foot aircraft-carrier hangar?

The taller structure raises topweight and metacentric-height concerns, so the designer must add or preserve balancing weight lower in the hull.

Hangar height cannot be increased without affecting the rest of the ship. More structure high in the hull adds topweight and changes the carrier's stability balance. The design must compensate with weight lower down rather than treating extra aircraft clearance as free volume.