Please have a look at the following link to the Broads authority website. I recently came across this article and whilst some of the advice and warnings are obvious to most, some are worth a look to make sure you are safe. In particular, the recall of certain Llytron and Powerplus gas alarms.
There are other items of interest around safety that are worth a look. Better to have a read and check some part numbers than have a terrible accident. A batch of Micromark fans are faulty and could cause a fire for example.
Please see this page or more information - http://www.broads-authority.gov.uk/boating/urgent-boating-news.html