Hello! I'm working on my first serious writing project and I keep running into the same question, "What system should I use, UK or US?" I'm from the US and I know a little bit about UK English and the metric system from school and through current research and I'm trying to decide which method would be best. My book is based in 1889 on a merchant ship (sail) that leaves port in England and follows an Englishman on his journey (first person POV). I envision this book would be geared to an American audience and I would also like to keep the authenticity of the story without getting confusing (or insulting anyone from the UK). I feel that if I were to substitute "45 metres" (when describing the boat's length) for "150 feet" I would come off as ignorant or worse, ruin the story. What is your opinion on something like this?