" I am AMAZED that this shows up in a list of the 100 best mystery novels of all time. The "plot" consists of the tale of two men sailing up and around the German coast pre-WWI, where there are innumerable sandy islands, sandy islets, and sandbars. Hence the name. But I felt I had experienced their sailing adventures in real time, all the while not understanding the plethora of sailing jargon used. Oh, well, I thought, some action has to come soon. There is a little action, and even a little love interest. So I hung on to the end, hoping for some resolution. There is none! We don't find out the secret of the mysterious Herr Dollmann, who is really a Mr. X from England, nor do we learn anything about the outcome of the love interest! It's all hushed up, we're told, to protect the identity of the traitor and his daughter. Waste. of. time. "
— Kathy, 2/5/2014