Are you thinking of Adge Cutler's 'Captain of a Dredger'. (from before his days with The Wurzel's!)? Martin Babb sings it down our end! Chorus goes:

" The chains go bang.
The buckets clang.
There is no vessel finer,
From Bristol docks down to Mumbles rocks,
Proud as an ocean liner.
Oh let the farmer till his field,
And the clerk stick to his ledger,
With a Yo, Ho, Ho, from the crew down below
I'm the captain of a dredger."

Was that it?

Tom