Thursday, 17 April 2014

Building the Devonport Column

Wikimedia Commons
I've not yet visited the Devonport Column, which has now been open to the public for nearly a year. But last year I had a look at John Foulston's The public buildings erected in the West of England as designed by John Foulston F.R.I.B.A. (1838), which has some background: "The manner of raising and setting the stones, in the erection of the Devonport Column is, he [the author] believes, perfectly novel, and will not fail to interest the young practitioner".

In 2013, I paid a visit to the Devon and Exeter Institution to research a piece on Foulston's "Hindoo" Calvinist chapel, a now-lost building in his Ker Street development for the newly-incorporated Devonport. Foulston's vanity-published The public buildings erected in the West of England also describes the Devonport Column.

I don't pretend to understand all the terminology; but the gist is that the stones were raised very neatly, without scaffolding, by hauling them to the top of a "Spar" (a stout vertical mast) that had a "Gaff" (an angled boom acting as a crane) at the top. As the height increased, extra sections were added to the top of the Spar, which was reinforced and braced to the already-built section of the Column, as required.

Foulston's book is distinctly self-promotional, and his grievances regularly surface in the commentary, as in the introduction to the Devonport Column section.
Commemorative Column, Devonport

This column, which was intended to be erected by public subscription, commemorates the change of the name of the town from "Plymouth Dock" to "Devonport", the authority for which was granted, agreeable to a petition forwarded to George IV, in 1823.

The Foundation Stone was laid on the 12th of August, 1824, and it was originally proposed to place a colossal statue of His Majesty on the summit; but certain individuals having refused to answer the engagements to which they had affixed their names as subscribers, the parties employed in the erection have not been paid; and there is, consequently, very little chance of its being completed in the manner originally contemplated. Instead of being a trophy, recording the honours which belong to a high sounding name, it is likely to remain a memorial of the neglect and injustice with which the indigent widow of the builder, and others have been treated, to whom considerable sums are now due.
Anyhow, here's how it was done:
This Column is built of a beautiful granite from a quarry near the Tamar. The Shaft is 11 feet in diameter—its height from the bottom of the Shaft to the top of the Capital is 65ft. 4in., being nearly six diameters. The Column makes, with its inferior and crowning pedestals, a total altitude of 101ft. 4in. Its height above the street, including the rock on which it stands, is 124 feet. Every stone was hoisted and set without the use of

scaffolding. The Abacus of the Capital is in four stones, each weighing between 3 and 4 tons.

The ascent is by a spiral Staircase within the Shaft to the Gallery on the Capital; which commands a prospect of surprising variety, interest, and beauty. "As you look down on the town of Devonport and its Dock-yard, and also on the extensive waters of Hamoaze, as on a map, where generally from 90 to 100 ships of war are reposing—the hills, vales, fields, woods, and waters, from Hengeston Down in the north, to the ocean in the south—from the wilds of Dartmoor in the east, to the billowy eminences of Cornwall in the west—lie below the gaze in a beautiful varied panorama." *


Plate 85—Plan at A, B, on section.

Plate 86—Plans at different heights, as described by letters of reference Figs. 1 and 2—Plan and section of Dowels, being of old ship timber—"heart of oak"; mortice holes were cut in the stones at each joint, as shewn in the plans, into which these Dowels were fitted, and swam in and plaistered over with Parker's cement. Fig 3—Cast Iron Rain Water Pipe.

* Vide Carrington's "Devonport Guide," p.6.

Plate 87—Elevation and Section

Plate 88—Fig. 1—Elevation of Capital and upper part of Column.
Fig. 2—Lower part of Column.
Fig. 3—Plan of upper and lower Diameters.
Fig. 4—Section of upper part of Column, shewing the method of securing the Echinus, (which was in 6 stones) by Irons, until the Abacus and other work was set over them.
Fig. 5—Method of Drawing the Echinus.

Plate 89—The manner in which the Stones were raised and set.

The Stones in the foundation, the Plinths, and the lower part of the Shaft, were raised and set with the triangle; those above in the following manner:—The end of a Spar a, 45 feet long, was let into the ground, erected and braced by the diagonal pieces, c,c, and lashed and strutted to the lower part of the Shaft, similar to the method shown at A,B, but afterwards removed for the support under, and to fix a second spar b; the end of top was secured by Guys R,R,R,R, strained tight by Blocks and Falls fastened to Piles driven into the ground at k,k, &c. A Gaff D, with Jaws at the lower end, was then slung in the throat by a strong Rope or Chain at s, so as to work round the upright Spar in the Jaws prepared for this movement, at the end or bottom of the Gaff, and placed at the height required for raising the Stone, as shewn in the upper part of the Drawing at D.

As the work proceeded, the second Spar b, 58 feet long, was hoisted and placed in the Cap F, supported by a Shore T under the heel, 15 feet long, as shewn from the Plinth, and braced to the Column and secured by Lashing and Guys in a similar manner (as shewn at A,B.) When more height was required for hoisting and setting the upper Courses, the third Spar n, 50 feet long, was hoisted with a Shore under o, 23 feet long, to lengthen it, and placed in the Cap L, lashed and braced to the Shaft of Column then built, and the top secured by Guys as before; and the Gaff raised and slung at the height required, as shewn in the drawing for hoisting and setting the top Stone.

By the Blocks and Fall, and the manner of setting the Jaws, and hanging the Gaff, it is easily adjusted and regulated, so as to bring the stone immediately over the spot on which it is to be set. The Fall for regulating the Gaff, being secured to a Cleet G, fixed in the lower part of the upright Spar A, at G.

The Stones are hoisted by a Crab or Windlass, secured to the pile H, driven into the ground, and by Blocks and Falls placed as shewn at I, I, I, I.

By proportionally increasing the size and number of the Spars, Guys, &c. &c., and having Blocks and Falls sufficiently strong, Stones, Statues, &c., of any weight may be raised to the height required.
Here are the plates: click to enlarge. I've done my best to correct for difficult lighting, and the inability to flatten the pages of this rare book.

Plate 85
Plate 86

Plate 87

Plate 88

Plate 89

Plate 89 (detail)

Plate 89 (detail)

- Ray

Thanks to the Devon and Exeter Institution for guest access to its library; all images are reproduced courtesy of the Institution

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