Before the Penang Bridge was built the only way for cars to travel between the island and the mainland is with the Ferry.
However, in recent years, there has been articles saying that this service will be retired since it is money losing operation. So if you ever come to Penang be sure to take the opportunity to use the ferry or you may never get the chance again.
Here are some nice pictures to share:
The ferries used to be all yellow but now they have different colors and each of them are named after an island in the country:
View from the ferry:
View of the island:
Oldest clock tower in Penang:
Approaching the dock: