John Fryer was one of the most important foreign translators in China after the Opium Wars. The work that is the final result of his experience at the Jiangnan Arsenal is The Translator’s Vade-mecum. Among the preparatory manuscripts of the glossaries that were published in the Vade-mecum, the author has identified the “Vocabulary of Terms in Naval Architecture.” The purpose of this article is to examine the main features of the Vocabulary, its sources and the peculiarities of the manuscript. In the first and second sections, the Vade-mecum is concisely analysed; providing numerous references and simultaneously sketching an outlook of the production and circulation of knowledge in the period considered, the author presents theoretical discussions concerning the norms of translation applied in the Vade-mecum, its purpose and the patronage of the translation activity. In the third and main section, studying the historical significance and linguistic quality of some of the translated terms annotated in the “Vocabulary,” the author compares its terminology with the concurrent Japanese one and with other Chinese relevant nomenclatures, demonstrating the complicate interaction in the “Vocabulary” between lexical innovation and recovery of existing terms.