I believe this subject has been aired before but since when did that make any difference...it's fascinating. As Brian Peters noted correctly (threads passim.) Bob Copper recorded a very fine and dramatic version from Ned (Wintry) Adams which has a quite different tune from the family's. In fact Bob was very taken with it and always put it down to the fact that it was sung by a proper sailor rather than a ploughman! Strange that the departure date in both of these versions is given as Valentine's day. Oh, you can also sing it to the hymn tune 'Immortal invisible God only wise'....'which is rather nice.