Britannia P&I Club has seen several pollution incidents involving the accidental transfer of cargo into an adjacent ballast water tank. The main causes are pitting or corrosion of cargo tanks which results in cargo being flushed out during ballast water operations. These incidents have highlighted the importance of crew awareness of ballast principles and best practices. In this guidance Britannia Club explores best ballast operation and how to maintain ballast tanks to prevent such claims. Continue reading “Ballast operation and maintenance practice”
Introduction
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.