Behind central station there are several ferries to Noord and to Java island. They take bikes and people are free. A v. easy way for a quick river cruise at sunset.
The council is always threatening to close down the longer routes, saying they make a loss. They probably do. But if your city is split in two, you need all the connections you can get.
Bus company Connexxion also runs a fast ferry service to Velsen, close to IJmuiden, which is a good way of cruising along the North Sea canal. If you want to use it to get to the beach, get there early so you can take your bike - it has limited bike places. Otherwise you need to take a bus... the stop is outside the ferry port.