1815 - Howe, wholly built upon Diagonal Bracing System

Robert Seppings, 48 years old, previously Master Shipwright at Chatham dockyard, now Surveyor of the Navy for two years, applied his system of diagonal bracing to the whole hull of a new ship, Howe, a tremendous 120. He also used iron knees in substitution for grown timbers, so difficult to find within sparse woods. Howe was the first of a class of three to be laid down in 1808 and is structurally different from her two sisterships, Nelson and St Vincent, laid down in 1809 and 1810 respectively and lately launched, which are built on a traditional framing,. St Vincent is intermediate in having iron knees as Howe. Externally they are identical, all benefitting from Seppings' round stern, much stronger than the previous shape. As for diagonal bracing, Seppings said he was inspired by the structure of Hans Grubenmann's Schaffhausen bridge, completed in 1758, that he was acquainted with through drawings and that he has imported in naval engineering, step by step, for fifteen years.

¤ In 1682, Bernard Renau d'Eliçagaray implemented diagonal bracing to build a holding structure under the heavy mortars of his galiotes à bombes. His solution proved to be efficient and reliable, as the bomb vessels withstand thousands of backlashes without any damage.

¤ In 1771, Gabriel Snodgrass, 52 years old then, Surveyor to the East India Company, proposed the Admiralty two innovative ideas : 1st, to replace grown timbers, so difficult to find, by iron knees ; 2nd to use diagonal bracing instead of traditional parallel one. He achieved to introduce iron elements into the Indiamen of his own design in the 1780s. It was not a premiere. Pierre Morineau, designer and builder of the outstanding 74 Invincible, launched in 1744 at Rochefort, already used iron girdles - a bold step forward then, even if Anthony Deane tried it in 102-gun Royal James as early as 1670.

¤ Joshua Humphreys, 64 by now, Master Naval Constructor of American Navy from 1794, to 1801 introduced diagonal bracing into the structure he designed for three large 1,580-ton frigates, Constitution, President and United States, launched in 1797-1800. He was pushed to this invention by structural strength required by extensive length and great fineness of the hull,. We know that he was inspired by Jacques Boux' 1430-ton frigate Indien, launched in 1777, renamed South Carolina in 1780, which was exceedingly large and fine, yet fitted with a heavy armament of twenty-eight 36-pounders and endowed with thick scantlings at the same scale as a 74-gun vessel. Was Indien fitted with diagonal bracing? We do not know but,, anyway, we may credit Humphreys with this invention or re-invention.

¤ By age and by position, Seppings was restricted to secondary tasks at Plymouth dockyard. He directly observed impact on ships ends of hogging and sagging, disjointing planks and generating leaks despite caulking. This is how he crafted diagonal bracing in the 1790s. He also promoted iron elements.

At Plymouth dockyard, Seppings earned a reputation for his ingenuity. He was seen and remembered by John Henslow, Surveyor of the navy until 1806, designer of 110-gun Hibernia, built at Plymouth, Master Shipwright there when Seppings started work as an apprentice. Henslow's patronage shaped his destiny. As Master shipwright assistant at plymouth, he was considered enough to be authorized to trial his system of a diagonal bracing at the opportunity of the refit of the frigate Glenmore in 1800. Then he invented a new system of wedges to support ship in dry dock, which resulted in a significant gain in fairing time - and in a £1,000 reward for him. Once appointed as Master Shipwright at Chatham in 1804, he can partly apply his system with some success to a ship of the line, Kent, during her refit in 1805. Then he applied it at some extent in the building of 74 Warspite in 1805-07 - a ship designed by Henslow. A last decisive trial was made onto 74, Tremendous, for her refit in 1807. He was then authorized to plainly implement it when Howe was laid down in 1808.

The 2,620-ton three-decker Howe is 205-foot long at the gun deck, 53¾-foot broad and 24-foot deep. She is armed with thirty-two 32-pounders, thirty-fours 24-pounders, thirty-four 18-pounders on her gun decks, and six 12-pounders and fourteen 32-pounder carronades on her forecastle and her quarterdeck. No ship can compare but 120 prototype Caledonia and French Océan-class vessels.

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IN RETROSPECT FROM TODAY

Note - On Seppings' innovations

Every new design will be endowed with diagonal bracing and with a round stern after Howe. Curiously the introduction of iron elements only applies on frigates while it is belayed on ships of the line after Seppings' retirement in 1831.

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SUGGESTED BIBLIOGRAPHY

Brian Lavery - The Ship of the Line : Design, construction & Fittings - London, 1983

Andrew Lambert - the last sailing battlefleet - Maintaining Naval Mastery 1815-1850 - London, 1991