How battleship and cruiser design roles diverged

Did armour distribution and hull form create the distinction between battleships and cruisers?

They contributed to the divergence, but contemporary designs could blur the line between an armoured cruiser and a second-class battleship.

The question frames battleships as broad, heavily armoured combatants and cruisers as narrower, faster ships with less protection. That distinction captures the emerging trade between protection, speed, and cruising role. The period resisted such a clean division because some armoured cruisers approached second-class battleship characteristics. USS Maine is offered as a borderline example, along with the assessment that her loss just before the Spanish-American War was probably accidental. Classification followed doctrine and institutional choice as well as dimensions or armour thickness. Applying later categories too rigidly can therefore distort nineteenth-century warship roles.