I continue my relentless 3*ing of the series, though this volume was significantly better than the previous one (The Slippery Slope). 
 Much of the action takes place on submarines. These submarines appear to contain cavernous, often rectangular rooms, although the first of them is encountered in a mountain stream... Later a submarine's window (yup, window) is repaired with chewing gum. 
 My science is further hurt by the claim that sonar of the type that puts a tracking dot on the screen works by listening for noise made on the remote vessels being tracked. 
 Let us put this aside and strive for the perspective of the child who is being read to (my daughter Celyn) ... although I do feel a book should offer some consistent vision that can actually be processed in the readers' heads. 
 Anyhoo - the primary characters offered this time (Captain Widdershins and his daughter Fiona, plus Olaaf, Esme and Carmalita Spats) are enjoyable / funny. 
 We see the good vs evil blurring continue, with good people turning bad, or at least less good and bad people turning good or at least less bad. We see new peril in the form of a weapon of mass destruction - a fungus that kills people, and the children's respective special skills of invention, research, and cookery are employed to good effect. 
 Inevitably Olaaf captures the children on / in his even huger submarine, and inevitably they escape. The pursuit of the mysterious sugar-bowl drives much of the action. We learn incrementally more about VFD and end up pointed fair and square at the Hotel Denouement where all will at last be revealed in book 12 ... or will it? 
 You should join my 3-emails-a-year mailing list for updates about my books. #prizes http://eepurl.com/cimnK1 
 ..