Approaching Hafen von Wyk on the German Frisian island of Föhr, I had studied the tide tables, chart and cruising guides describing the narrow, shallow, dredged channel with shoals on both sides. The channel is unmarked except for a single buoy south of the entrance (to port upon entering). The cruising guide warns of strong crosscurrents, many ferries and an expectation of strict adherence to Navigational Rules. I know the Rules well and observe them carefully but was appreciative of being reminded.
As we passed the lone buoy well to port and entered the channel, I could see a large ferry at the terminal. I was not at the helm and could not see our position on the chartplotter relative to the edge of the channel but was comfortable that we were well to the proper right (north) side.
As we proceeded in the channel, the ferry got underway towards us. Initially, with little way on, she headed 60º into the cross current and crabbed into the channel, appearing to approach us sideways and using quite a bit of the narrow channel. Not being able to quickly glance at the chartplotter and with no lateral marks to guide us, I was unsure whether we were close to the center of the channel, and obstructing the ferry, or about to run aground on the shoal outside the channel. I made a quick decision and directed the helmsman to reverse course back into the deep water and let the ferry have the whole channel.
Once the ferry gathered way, she was able to head more directly out of the channel. I had no idea what course the ferry wished to follow once outside the channel and again decided to stay out of her way by moving as fast as possible to the south side of the single buoy, completely out of the channel.
By this time, the ferry had gained considerable speed and we were unable to get beyond the buoy before the ferry altered course to port and we passed starboard-to-starboard.
The ferry captain and I made eye contact as we passed and it was clear that he was not happy. Thinking about it from his perspective: he likely saw us entering the channel on the proper side before he got underway and expected a routine port-to-port passing; he was somewhat perplexed when we reversed course; and was alarmed when we crossed his bow and passed starboard-to-starboard. In retrospect, I should have allowed the helmsman to hold our original course in the channel and stay right until it was clear from the depthfinder that we were at the edge of the channel.
Both of my well-intentioned decisions had been wrong.