On the principle that a ship should be able to receive the fire that she could give, the Duilio's armour-belt had to thicken from about 12 inches to 20 inches.
Ngoko mthetho-siseko lenqanawa mayikwazi ukufumana umlilo owuthi ukwazi ukuwunika, iDuilio amacangci okunqabisa inqanawa nebhanti makaqhine ukusuka kwishumi elinesibini le-iintshi ukuya kumashumi amabini ee-intshi.