I got my tickets and the bike is at the port.
Actually, there is no daily ferry service between Jeddah and Suakin (Sudan). The schedule seems rather flexible depending on expected traffic. I was a bit lucky that there is a ferry departing Jeddah tonight to reach Suakin around noon tomorrow …
Namma International seems to be the only (somehow regular) operator between the two ports.
Namma’s office is located just off King Khalid Road, not far away from the port. (Google Maps Coordinates 21.4689449,39.1850036).
At Namma’s office, I met a nice Egyptian gentleman Mohamed Hussein who spent 11 years in the Netherlands and was able to throw in few words of German into our conversation. He and his Sudanese colleague were extremely helpful in getting me the tickets at a total price of SAR 1,630/EUR 390 (SAR 600 per pax, SAR 800 for the bike + 230 harbor fee).