This quite literally striking triologism is from a poem by Robert Lowell (1917-77), which I discovered in a commentary by Seamus Heaney on Lowell’s hard-hitting ‘The Quaker graveyard in Nantucket’:

When the whale’s viscera go and the roll

Of its corruption overruns this world

Beyond tree-swept Nantucket and Woods Hole

And Martha’s Vineyard, Sailor, will your sword

Whistle and fall and sink into the fat?

In the great ash-pit of Jehoshaphat

The bones cry for the blood of the white whale,

The fat flukes arch and whack about its ears,

The death-lance churns into the sanctuary, tears

The gun-blue swingle, heaving like a flail,

And hacks the coiling life out…

The full poem can be found on the Poetry Foundation website, along with a biography of Lowell.

‘Swingle’ means both a wooden tool for beating flax and its related verb; it also refers to the swinging part of a flail.

Source: Seamus Heaney, Finders Keepers: Selected prose 1971-2001 (London: Faber and Faber, 2003), p. 207