I didn't know about this Kiel canal until I restarted my career to wilhelmshaven. In fact the reason I restarted my career was because it took a really loooong time to sail from the base in Kiel to the North sea, espescially in a type IIA boat.
It wasn't until my 2d partol (in second career) that I found out about the Kiel canal. I accidentally clicked on the "Kiel canal" navigation mode and afterward searched the map and realized that there's a shortcut from Kiel to North sea.
