Book excerpt: Diesel engines are installed in just about every yacht and in most large motorboats and, while professional help is often at hand, sometimes it is not. Indeed, engine failure is one of the most frequent causes of RNLI launches. This book explains how to prevent problems, troubleshoot and make repairs using safe techniques. It could also help you save money on expensive bills for yard work you could do yourself. Diesels Afloat covers everything from how the diesel engine works to engine electrics, from fault finding to out of season layup. With this guide and your engine's manual you can get the best performance from your boat's engine and be confident in dealing with any problem. The book covers the syllabus of the RYA Diesel Engine and MCA Approved Engine (AEC-1) courses. This edition has been thoroughly modernised and updated by former course lecturer and currently chief engineer on merchant ships, Callum Smedley.