HULL GATES SHIPPING CO. LTD.
image by Jarig Bakker, 15 August 2004
Stewart 1953 and 1957 combine the H158 flag with the H157 funnel.
Mitchell shows the H with a longer leg towards the hoist of the panel.
Coastal Ships 1967 specifies a narrow black funnel top. The National Maritime Museum flag reproduced on FOTW is dated about 1951; its dimensions are printed in the source as “1016m x 1371.6”, with the unit left unresolved.