It's best a capella, to my taste, but worth doing any way you can. There was a beautiful recording on the "Silly Sisters" LP in the 70's by Cilla Fisher and whatshername (ah, memory!), with fantastic two-part harmony and a kind of drone accompaniment. Haunting. The "Grey Funnel Line" refers to the Royal Navy, with a play on the names of steamship lines of an earlier day.