Records of Humber Conservancy and the Humber Ports (Records deposited by Associated British Ports and its Predecessors) > Humber Conservancy > Humber Conservancy Board: Technical drawings of Buoys, Launches, Lightvessels and other ships submitted to the Board by Manufactures and related papers > Buoy Servicing Vessel (Yard No. S. 850): Lloyd's Class + 100 A1 "Buoy Vessel" for restricted service > Drg No. 7116/72 'Henry Derrick Stool and W. T. Hatches' Yard No. S. 850