The case study for the redesign of a floating device able to produce electric energy from sea waves is presented. In particular, the steel hull of the ISWEC set up by the spin off "Wave for Energy" of the Politecnico di Torino has been converted in ferrocement without changing the total mass displacement and the position of the centre of gravity. Moreover, the essential ferrocement technology is illustrated, stressing the main differences with respect to the reinforced concrete. A reference guide useful for the early stage design scantling of small ferrocement crafts has been adopted for the specific case studied.
