Like the best of this author's other books (The Maplin Bird, Sea Fever), this adventure is centered on, but not dominated by, sailing. Actually Paul Fairfax, the main character is unenthusiastic about boats and clumsy at handling them. He's incompetent and error prone in practically everything, in fact, except for obsolescent farming duties. Of the three boys this book deals with--Paul, his older brother Chris, and his friend Gus--Paul is the only one who loves the tiny, desolate, old-fashioned seaside down Birdsmarsh and who resists the plan to build a modern marina on his family's farm. Gus is forced to support his poor, rather decadent family, and longs for an escape, and his only joy is Paul's unwanted smack Swannie which Gus insisted on making seaworthy. Chris has escaped; his interests are intellectual and he is bent on success. He has invented a special life-saving suit and enlists Paul's and Gus' assistance in following him around in Swannie to see if the suit will keep him afloat and warm. But Paul is the one who divines an attempt to sabotage Chris' trials and steal the patent, who is alone on Swannie when it sinks, and who makes the real test of the suit-- as well as of himself. The three different points of view, all equally valid, are very well demonstrated, and the book offers some vitally suspenseful movements.