This is an appalling book. It is badly proof-read, badly edited and contains far too much foul language.
More seriously, the plot is just a mess. Framed in the tired old 'dying man tells his story in old people's home' format, it is basically an account of the escape of a naval POW who is used by a high ranking Gestapo officer for his own ends. But too much time is taken up on his escape; the portrayals of the people involved are simplistic (all the Gestapo men seem to be fat, for example - why?); and the information he unwittingly carries out when allowed to escape is paltry and has seemingly no bearing on the final outcome.
There are multiple inaccuracies, especially as regards the last week or so of the Bismarck's career. Lutjens was not captain of the ship; Bismarck's steering was not damaged by the Prinz Eugen, which had been detached soon after the sinking of the Hood, but by a British torpedo dropped from a plane; the whole account of the final battle is inadequate. The Home Fleet C in C Admiral Tovey is suddenly mentioned in the final pages with no previous introduction. The name of one ship is changed from Dorsetshire (correct) to Devonshire (incorrect) in two pages.
The dust jacket says that the author is one of the most borrowed from UK public libraries. This is a sad indictment of those libraries and their readers: I shall not be borrowing another of this author's works.