Why early Royal Navy promotion had no normal timetable

Was Byng's rapid rise through the admiral ranks normal for the period?

There was no dependable timetable: seniority mattered in theory, but battle opportunities, luck, political patronage, and a strong sponsor could accelerate a career dramatically.

Byng rose from lieutenant to rear admiral in roughly fifteen years and from rear to full admiral in about five. That path should not be read through a modern standardized promotion schedule. Seniority was an official principle, yet wartime service and participation in a successful battle could create openings. Byng also possessed the decisive patronage of Edward Russell, so competence, opportunity, and connection reinforced one another.