Crimes on the seas are by no means isolated cases and the websites quoted in the book, which act as forums for victims, relatives and lawyers, do actually exist. The incidents they document have reached such proportions that the International Cruise Victims Association (IVC) is calling for ‘sea marshals’ which, unlike air marshals on aeroplanes, don’t yet exist. These floating hotel forts are small towns without a police station. If there are any security personnel, these are financially dependent on the cruise line, which means in an emergency it’s unlikely that their own staff will be subject to scrutiny.

In all honesty, however, it must be stated – and here the facts in the book are equally true – that even a sea marshal would be able to do little when a person goes missing. The several-kilometre stopping distance of a cruise ship alone precludes a rescue operation with much hope of success, especially if the potential victim has not been seen for several hours. And, as has been adequately described, the ship itself is far too big to permit a thorough and rapid search.

Moreover, no uniform global regulations exist for such cases. As Martin Schwartz notes critically in the novel, the moment passengers board a ship they are stepping onto foreign soil, while Kendall Carver from ICV points out that they’re at the mercy of the authorities of the country where the ship is registered. For this reason, in 2010 the USA passed a law giving the FBI and the US Coast Guard wide-ranging powers, according to which officers from these bodies can launch investigations even on ships registered in foreign countries. But only following the disappearance of an American citizen.

Researching the subject was very simple so long as it related to the areas above the waterline. Deck and cabin plans, video documentation of the bridge, TV reports – all of these are only a mouse click away. It’s more difficult getting information on crew accommodation, the anchor room and the kitchen, but during a research trip I was permitted to go on a tour (before those responsible knew what my book was ultimately about). It is almost impossible (for security reasons) to access complete plans of the lower deck including machinery and cargo rooms, or the waste incineration unit.

*

I come now to the official acknowledgements, beginning with a warm thank you to Captain Volker Bernhard, now retired, for his expert advice. He took the trouble to read the novel in advance and gave me valuable insights into those areas that would usually remain off limits to an ordinary cruise passenger like me.

All the mistakes that are still in this book are on my sailor’s head and, as usual, are rebuffed with the standard excuse of creative people: ‘It’s artistic licence!’