Yes they do go North, Or just the fishing get's good from South to north, as the lake warms.
Here's a map of South Haven. The launch is at the black River Park. Take exit 22 to the West, go to the Blue Star (first street). Go South to 2nd ave/E Wells. then West till it ends. The launch is right about 100 yards. It has a machine to take your money. $6.00 I think?