Protection and numbers instead of a fleet of first rates

The class carried an armoured deck over its machinery, coal bunkers around vulnerable spaces, and timber over its iron or steel hull, giving a relatively small cruiser some ability to absorb punishment. Its broadside was also strong enough to discourage most small warships encountered on distant stations. This practical protection cost far less than building an entire global fleet from first-rate ironclads such as HMS Warrior. The most advanced ships lost first-rate status quickly as technology changed, even when later refits kept them useful. Cheaper cruisers provided numbers, were easier to replace, and reserved the costliest combatants for missions that required them.