This book is aimed as a practical guide for anyone planning to build or modify a boat starting from an existing GRP hull. Every aspect of the building project is covered, from basic concepts, planning, organization and building to the final polish on launching day. The problems likely to be encountered are discussed, as well as the reasons behind decisions and compromises made. It explains a number of problems such as what to look for when buying a glassfibre hull; how to calculate how much anti-fouling will be needed; what are the best materials to use for fuel tanks and how to fit a VHF radio.