The aim, with LPG, was to improve boater safety by reviewing key elements of gas safety, while linking design, commissioning and maintenance together as crucial factors to gas system success. There is scant academic work existing that relates to the inland waterways, and virtually no academic research into gas safety on boats. It is hoped this project will open the debate and encourage other projects.
Why LPG on boats?:
- LPG is in widespread use on boats for cooking and heating: with an estimated 60,800 of 80,000 vessels, or 76% understood to have LPG systems.
- The sector is undergoing demographic change: it’s estimated the liveaboard population has grown from 15% in 2011, to 27% in 2020 (CRT research).
- There are areas of intense concentration of liveaboard boaters, for example there are an estimated 5,000 liveaboard vessels in London alone (CRT research in 2018), mainly off-grid and using LPG daily.
- Correct gas system installation, testing and maintenance is obviously crucial to safety.
- But it’s not just fire and explosion risk, longer term health considerations, such as chronic CO exposure and other products of combustion e.g. formaldehydes, needs to be considered.
- Academic work in other sectors shows link between neurological illness and poor appliance operation; Prof Ben Croxford is a notable author in this area.
Marine surveyors and boat owners are regularly heard to say there is a minimum 4.0mm of hull thickness required at time of survey of a steel narrowboat. Some brokers even publish videos of such information, with some surveyors enforcing it (Whilton Marina, 2012 and 2016). Boaters are subject to it and repair often follows. In a recent article, Geoff Waddington (2021) explains there is confusion in the industry about wastage limits, and consequently acceptable residual hull plate thicknesses, and opinions among surveyors ‘vary wildly’, with some quoting 3mm acceptable minimum plate thickness, others using percentage loss. This short paper explores what a standardised acceptable limit for diminution, and therefore residual steel plate thickness for narrowboats, could be. It describes a variety of methods of calculating the design plate thicknesses (scantlings) and the minimum acceptable residual plate thickness. In doing so, this paper aims to serve as a guide for inland waterways marine surveyors, boat owners, repairers, and insurers alike. 
