How British 18-inch work shaped treaty pressure

Did the 18-inch gun fitted to HMS Furious influence American interest in treaty calibre limits?

Yes; it signalled that Britain could field the calibre, encouraging a limit before rivals felt compelled to follow.

HMS Furious and British heavy-gun work help explain the incentive for naval-arms limits. If Britain fielded a larger gun, rival navies would face pressure to match it even if they considered the jump wasteful. A negotiated ceiling could prevent that escalation and its industrial cost. Treaty making could therefore respond to anticipated competition as well as to ships already in service.