The tourist office has maps for scores of bike rides along the waterfronts.
Follow Kiel’s main thoroughfare, the pedestrianised Holstenstrasse, for about 1.5km northeast to the Schlossgarten to reach the waterfront (the port closer in is inaccesible due to ferry terminals). Amid the sparkling waters, you'll see new warships being built for nations worldwide and all manner of ships big and small.
Kiel is best visited on your way to someplace else. Follow the waterfront and choose a seafood cafe for lunch.