Answer:
Vancouver island is separated from Vancouver with a body of water called the Georgia Straight. The Georgia Straight measures 18.5 km wide at it's narrowest point and 55km at it's widest point.
To get from Vancouver you need to take a ferry from either Tsawwassen Ferry Terminal (about a 40 minute drive) or Horseshoe Bay Ferry Terminal (about a 40 minute drive). The ferry ride to Duke Point in Nanaimo is about 120 minutes and (38 nautical miles) and the ferry ride to Schwartz Bay in Victoria is about 95 minutes (24 nautical miles). Note that ferry times and distances are from Tsawwassen Ferry Terminal.