Queen Mary's proven 13.5-inch armament made her a safe fleet addition, but one-off battlecruisers could instead have carried more experimental machinery and weapons. An entirely oil-fired Queen Mary could have tested propulsion before the Queen Elizabeth class, just as a 15-inch-gun Tiger might have exposed problems before multiple battleships depended on the weapon. HMS Warrior provides the comparison: separately tested technologies produced a decisive combination when brought together in one ship. Coal's worldwide infrastructure and the battlecruiser's imperial cruising role still provided strong reasons for caution. The choice lay between experimentation and operational reliability.
Notable Point · 22:40-27:03
Could battlecruisers have served as technology testbeds?
Queen Mary and Tiger might have tested all-oil propulsion and 15-inch guns before those technologies reached the battle line.