The Fire Industries Association (FIA) has published a brief guidance document on the fitting of smoke alarms on boats. This guide is aimed at for boats up to 24 metres used for leisure, hire or residential purposes and covers such issues as types, where they should be located and how many should be fitted.
The guide can be downloaded from the FIA website at: https://www.fia.uk.com/news/fact-file-70-smoke-alarms-for-boats.html