Quite excited about this one. Came across it quite by chance.

1835
From: A Home Tour through the Manufacturing Districts of England by Sir George Head. 1836
Chapter 15.A Voyage from London to Hull by the Gazelle (steamer)
He describes the docks and river front as he arrives, and then witnesses the arrival of a Greenland whaler and the boys climbing up the rigging to retrieve the garland. As most of you know, unlike the American whalers that tried the blubber for the oil on board, the British ships brought the blubber back and it was tried in the 'Greenland Yards'. He describes the process in great detail.
After witnessing the boys climbing the rigging he goes back to the whaler in the dock the following morning. p246
'The next morning when I repaired to the docks the sailors were busily employed on board the whaler, and merrily singing at the windlass, as barrel after barrel was hoisted upon deck.'

Not only have I no references to singing at shipboard tasks for British whalermen, I have no references to Hull sailors singing at their work at all upto 1900, let alone this early.

I'd be interested to know what Gibb thinks of this.