Fear of surprise commerce raiders helps explain why the construction program included so many cruisers. Second-class protected cruisers offered a practical counter. Their batteries included six-inch and 4.7-inch guns, supplemented by armor and torpedoes. With speeds approaching twenty knots, they were slower than the quickest liners but could intercept them when directed toward a known position.
Chapter · 13:47-14:38
Protected cruisers answer the commerce-raider problem
The Act's numerous second-class protected cruisers combined useful speed, six-inch and 4.7-inch guns, armor, and torpedoes for pursuing threats to British trade.