Pretty much.
The centre of the city (which has always attracted the most amount of people day in and day out) is on a river, but the metropolitan focus is on the bay. [But many people live near neither!].
There's two layers of (200 year old) naval protection in Melbourne:
1. The heads /
The Rip (entrance) to Port Phillip from Bass Strait (The Southern Ocean).
2. Melbourne (named for the UK Prime Minister at the time) was built about 5-6km (following the old course of the Yarra) upstream of Williamstown (named for the King at the time - and Williamstown was originally envisioned as the centre of the Port Phillip district when Europeans first settled).
If Williamstown was the centre of the city, there'd probably be a much bigger maritime focus re: every day life.