 At his death the 'port of Whitehaven' had 77 registered vessels, totaling about four thousand tons, and was exporting over 35,000 tons of coal a year.Lowther had married Jane Leigh, a ward of his uncle Sir John Lowther of Lowther (because a daughter (by her first marriage to Woolley Leigh of Addington, Surrey) of Elizabeth Lowther (née Hare) who had taken as her second husband Sir John Lowther of Lowther).Lowther and Jane had three children