Astraea concentrated armour on the protective deck, gun shields, and engine hatch. This kept weight below battleship levels while giving the machinery and hull structure localized protection. Similar structural arrangements appear in the Apollo and Edgar classes, placing Astraea within a broader line of British cruiser development. A protected cruiser could shield vital spaces without carrying a battleship-style side belt.
Notable Point · 31:37-32:46
How protected cruisers shield machinery without a battleship belt
Astraea's protective deck, gun shields, and armoured engine hatch show how cruiser structure concentrated protection around vital spaces.