"18.17... it is important to note that although both chutes were found on the wreck to be open both in way of the non-return flap and the internal top cover, there is no known mechanical reason why this was so." (Report of the 2004 Re-opened Formal Investigation into the Loss of the FV Gaul)
In the paper describing the MAIN DESIGN FAULT on the Gaul, we gave an account of how the closed flaps of the duff and offal chutes on the vessel could have been forced open by the sea at the time of the incident. (You can also see a model of the design fault captured on this VIDEO clip).
Furthermore, the factor tree analysis diagram, published earlier on THIS PAGE, presented a range of alternative explanations, as to how the outer flaps of the duff and offal chutes on the Gaul could have become open and remained in the open position (the RFI having only examined and accepted that the flaps were open, prior to the vessel’s departure from Hull, as a result of corrosion and lack of maintenance).
One of these alternative explanations (i.e. THE SECOND DESIGN FAULT), mentioned in an earlier POST, put forward the possibility that the bolted non-return flap assemblies within the chutes could have become twisted due to wave action and remained open as a result.
Today, we are presenting another alternative explanation, whereby a simple dimensioning error in the shipyard’s construction drawings meant that, if ever the brass gland within the flap hinges was loosened by the operation of the flap, parts of it could have bound together, thus causing the flap to remain seized in the open position.
THIS PAPER gives the details.