Failure of Ship Hulls Due to Rot
British oak forests provided the wood to build the fleets that fought the Seven Years’ War, American Revolutionary War, French Revolution, and the Napoleonic Wars. New trees had to mature for 80-120 years for shipbuilding. By the early 1800s, three-quarters of British oak forests had been harvested to fight a half century of naval wars. Additionally, a scourge of dry rot reduced the service life of Britain’s main battle ships from the historical 25 years to less than 7 years. Britain had a severe national security problem – the Timber Crisis.
If the ships could last longer, new ships would not have to be built to replace them, so the stock of British oak trees could recover. Preservation of the fleet had a direct effect on Britain’s ability to build a fleet to maintain the Empire. Authors with diverse backgrounds wrote books that capture contemporary thinking about physical asset management, preservation, and repair.
Naval technology changed slowly in the age of sail. Ship construction, materials, and maintenance methods changed slowly as well, relative to the changes that would come in the mid-19th century with the introduction of metal hulls and steam propulsion. The British developed management systems for hull maintenance rooted in detailed record-keeping of expenses. This culture of record-keeping originated in their human resource and logistics support systems. Records of maintenance spending allowed attempts to conserve resources by ensuring the reliability of hull systems.
The investigations sponsored by the Royal Navy into rot would have important consequences. The body of literature that the navy sponsored in this period shows that the Admiralty was conducting a conscious research program into improving hull preservation. The Admiralty took input for the mining and building construction industries as well as one of the premier research institutions, the Royal Society. The program had multiple independent researchers and was sustained over many years. The researchers read, critiqued, and cited each other’s work. The overall goal was to extend the lifecycle of major national assets, extend the period of time between major repairs, and conserve scarce labor and timber resources.
1812 – Pering: A Brief Enquiry Into The Causes Of Premature Decay, In Our Wooden Bulwarks: With An Examination Of The Means, Best Calculated To Prolong Their Duration.
Pering was intimately involved with ship maintenance. He was the Clerk of the Cheque at the Plymouth dockyard. This facility is currently called His Majesty’s Naval Base Devonport and still maintains the Royal Navy. Pering had been a shipwright, a ship surveyor, and a dockyard storekeeper, so had 30 years of experience with how material and money moved through four different yards.
Pering estimated that a 74-gun ship required 2000 trees, or 50 acres of growth, at a cost for the hull of 100,00 pounds sterling for the hull. Sadly, hull life was limited to five or six years, and perhaps could be routinely extended to eight years with good preservation.
Pering addressed timber sourcing, methods and materials used in fastening, material choices during construction and repair, and methods of caulking. Caulking was routine maintenance activity. If caulking was compromised, a ship would leak more seawater into the bilge and rainwater into the upper decks, accelerating the rot problem.
Rot advanced quickly when the ship was in storage between conflicts. At best, the ship was hauled up onto a dry slip and covered. At worst, the ship was left waterborne, exposed to the weather. Without a crew to maintain the caulking, it would begin to decay almost immediately, wasting the precious oak.
Pering compared naval to merchant ship lifetimes, and argued for adoption of better preservation. The justification was to save timber, extend service life, and avoid replacement cost. He advocated for a replace-or-repair decision that would limit the maximum economic repair cost to one-third of the replacement cost. This was a level of repair analysis, but it was not the first. In 1749, only two years before becoming First Lord of the Admiralty, Admiral George Anson had advocated for a 25% repair versus replace decision. (Rodger p. 66)
1815 – Bowden: A Treatise on Dry Rot
Reliability includes the need for something to function for a specified period of time. Bowden used the term “durability” where modern readers would use “expected service life.” Bowden asserted that there had been a decline in the “durability” of the Royal Navy’s ships. Not only was this decline obvious in absolute terms, but it also existed relative to the durability of French ships. Bowden used market and prize court sale values to compare the depreciation of British and French ships in 1759 and 1815. In the preface of his book, he showed that the decline in reliability of British ships was worth about 30% of the resale value compared to the French standard. This loss of service value was something that should be investigated and corrected “…until the navy of Great Britain be as remarkable for durability, as it is eminent for glory.”
Charles Derrick’s 1806 Memoir of Rise and Progress of the Royal Navy was a major reference. Bowden and Derrick both worked for the Navy Office. Both had served as a chief clerk.
Gabriel Snodgrass was the head naval architect for the East India Company for 40 years, and had built or repaired almost a thousand ships. In 1771, the British Navy asked Snodgrass for a design review of navy frigates. Snodgrass presented his conclusions in testimony before Parliament, so Bowden and others had access to it.
In 1771, East India Company ships on average, made four trips to the east “with tolerable safety, by constant repairs, which were attended with great expense” before being broken up. (Bowden p 74) By 1814, they made an average of six trips east in their lifetime. The improvement in the East India Company’s asset lifetimes was confirmed by JR Harris in his 1966 article “Copper and Shipping in the Eighteenth Century.”
Bowden argued that the conditions of service faced by East India Company ships confirmed his theories about the conditions that triggered the initiation and propagation of oak dry rot. He also used initiation conditions he observed in ships in storage and in wooden houses as evidence in his theory.
Bowden quoted 44-year-old Parliamentary testimony from Snodgrass about the effects of building ships out of timber that was felled in winter. They agreed on the need to keep ships out of the water during construction, storage, and repair. Bowden repeated Snodgrass’ prediction that use of timber could be cut in half by adopting these maintenance practices.
In 1818, Bowden’s book was awarded with a gold medal by the society that eventually became The Royal Society of Arts.
1815 – Dodd: Practical Observations on Dry Rot in Timber
Ralph Dodd was a prominent civil engineer known for major bridge, tunnel, and canal projects. Dodd was a serial entrepreneur, known for promoting concepts, securing funding, kicking off projects, then leaving execution to others.
Dodd’s 1815 book about dry rot was only 63 pages. Dodd made analogies to the use of timber in mines and the use of mine ventilation equipment.
Dodd was a proponent of a chemical treatment he called the Dry Rot Preventive. He also advocated for forced ventilation as the main factor that could be improved to extend the asset life of sailing ships. Dodd drew from his success in inventing a mechanical blower that could be worked by two men and could move “hundreds of gallons of air” through a hose “like the East-India hookah pipe.” The hose could be moved to discharge into stagnant enclosed compartments anywhere in the ship. This was also to help in shipboard firefighting.
Dodd also advocated for ship and building design that included more openings to encourage movement of air. He also promoted the use of more iron in ships and buildings. This change in construction material would eventually solve the Royal Navy’s dry rot problem, but not for another half-century.
1815 – Wade: A Treatise on Dry Rot in Timber
Thomas Wade described the decomposition process in timber. He described the progression of rot, something most other works ignored. He also discussed soaking timber in salts, prior experiments with seasoning, and impregnating timber with resins. The last chapter discusses the chemistry of air, water, hydrogen, and nitrogen. Wade criticized storage piles and leaving the new frame of a ship exposed to season in the weather. He also advocated for building ships under cover.
Wade related a 1684 observation about the timber harvesting method and durability of timber used on HMS Royal Sovereign. After 47 years, her timber was too hard to drive a nail into. He made an example of the HMS Royal William which was built in 1719. This ship was nearly 100 years old, proving that long service life was possible without rot. The refit history of the second half of the ship’s life is transcribed on 3 decks.org, and shows the regular visits that HMS Royal William made to the yards for preservation and repair.
The appendix contained a series of letters that gave Wade permission to access HMS Eurydice at Deptford, and HMS Tribune and Hawke at Woolwich to experiment on. Wade died before he could conduct the experiments. In an incredible move, the navy offered that his wife could conduct the experiments instead, so they must have had some confidence in her grasp of the subject. Elizabeth Wade actually published the book and probably deserves author credit.
Most of the letters were signed by the naval architect Robert Seppings, who was a master shipwright in the Portsmouth yard. The following year, Seppings was appointed Surveyor of the Navy. The other people who signed Wade’s letters were all Commissioners of the navy: Henry Peake, Henry Legge, and Francis John Hartwell. Wade’s experiments to prevent rot were conducted with the full cooperation of the navy’s administration over the course of three years. The Wades’ work was part of an intentional research program.
1817 – Chapman: Preservation of Timber from Premature Decay
William Chapman related experiments inspired by the state of the HMS Charlotte. He reported the results of experiments by treating wood on existing ships with various chemicals.
Chapman also included a chapter on how to prepare a fleet for long periods of storage. He cited 1666 correspondence between the Journal des Sçavans and the Philosophical Transactions of the Royal Society to justify a proposed method of charring the hull to prevent shipworm attack. These journals are, respectively, the oldest academic journal, and the oldest continuously published scientific journals in Europe. The reference was 150 years old at the time of Chapman’s writing…in 1817, there was already a century and a half of academic writing on preserving ships.
Chapman also used contemporary research. He quoted extensively from Wade’s 1815 A Treatise on Dry Rot in Timber. Chapman also quoted from books about timber and rot by Bowden in 1815, Layman in 1813, and Pering in 1812. In his introduction, Chapman thanked Knowles for his help. (Knowles would publish his own work in 1821, see below.) Chapman had the cooperation of a navy board member, showing that the navy was sponsoring another research campaign. Chapman’s references show the breadth of the navy’s intentional research into mechanisms, causes, and prevention of rot. It also shows that the investigators had a knowledge network and a written body of knowledge.
Isaac Blackburn operated a commercial shipyard at Turnchapel that built at least two 74-gun frigates and a sloop between 1807 and 1812. The sloop, HMS Derwent, was part of Great Britain’s first squadron to enforce the ban on slave trading. Blackburn wrote several other books on naval architecture and practical shipbuilding.
He discussed the durability of timber as a result of the climate where the tree grew. He focused on how wood microstructure resisted frost, heat, dry, and wet when used in ship construction.
Blackburn compared harvesting methods and how they affected the durability of the timber. He discussed caulking in tropical climates, painting, and ventilation of ships in storage. This was not simply a book on shipbuilding, but was intended to identify the best methods in construction to minimize repair and lengthen service life.
Finding a practical method of ventilation was a major concern to reduce rot and fungal growth. Ventilation experiments were directly meant to preserve the hull and prevent the need for repair and replacement of major pieces of structure. The attempt to ventilate ships, especially in storage, was an attempt to preserve the asset’s capability, the very definition of maintenance.
1818 – Bosquet: A Series Of Essays On Several Most Important New Systems And Inventions: Particularly Interesting To The Mercantile And Maritime World, Ship-Builders, Underwriters, Mariners, And All Seafaring Men
Abraham Bosquet wrote a book that contained multiple proposed inventions that all related to preventing shipwrecks, recovering survivors, or property. He is sometimes credited with development and promotion of an early lifejacket. He had been promoting his ideas since at least 1802 in the Naval Chronicle. He also wrote a history and guide to duelling.
Bosquet claimed to present “An obvious plan of ways and means for preventing that rapid decay to which vessels…are at present subject…” He justified the effort by characterizing the economic loss of a ship as preventable. He listed specific ships that he claimed were lost “…by ignorance of herein discovered ways and means of preservation.” Methods were known to prevent the decay that led to loss of assets, so they were financially worth pursuing.
Bosquet reported the life of warships as 12-13 years. He approached the extension of service life economically:
The Boston, a 32-gun frigate, of 676 tons, was built in the River Thames in the year 1762, for 7,534 £.; between which time and 1781, a period of 19 years, there was expended on her in repairs in the King’s yards, the sum of 9,522£., and in 1783 she was repaired by contract, in Mr. Perry’s yard, for 14,234£.: again she was repaired in 1791, after a lapse of only 8 years from the repair by contract which had cost such an enormous sum, at the expense of 14,453£.; at which time, a new ship of her size and class (at the contract price then paid, viz. 12£. 4s. per ton) would have cost no more than 8,247£.!!!
Bosquet applied a level-of-repair analysis test to the navy’s practices and concluded that repairs had been a waste of resources.
He observed that some ways to preserve ships were known but that the root cause of dry rot was not fully understood. Foul and damp air were again cited as the cause of the decay of the ship. Bosquet attributed damp air to minor seawater leaks, making caulking an important preservation job.
One proposal to deal with decay was to increase the thickness of the planks, to allow for more time before the rot penetrated. Another solution was to prevent or slow rot by applying hot pitch. Like previous writers, Bosquett advocated filling spaces between planks and timbers. He mentions several times that he presented his ideas and was recognized by the Royal Humane Society. The Royal Humane Society primarily was concerned with drowning and shipwreck. Bosquett’s book was not revolutionary and he had other interests than asset management, but this showed that maintenace methods were being discussed in relation to asset life-cycle economics by multiple authors during this time period.
1818 – McWilliam: An Essay on the Origin and Operation of Dry Rot
McWilliam’s 1818 An Essay on the Origin and Operation of Dry Rot was not an essay, but a 420-page tome. The distribution list included Knowles, the famous fighting admiral Lord Exmouth, the 1st Lord of the Admiralty Middleton, and other Navy Commissioners and senior admirals.
McWilliam was an architect, so had experience with dry rot in buildings. Buildings could not be docked and rebuilt as extensively as ships. He argued that replacement of building components to stop rot slowly degraded the structure over time, changing its load-bearing characteristics. Repair was barely effective, so prevention was the only reasonable approach.
McWilliam criticized simplistic investigations of dry rot. Simply removing the rotten pieces, or simply removing the fungi failed to prevent much. Replacing parts was not a root cause analysis; the actual problem was never solved.
“Some men of science, indeed, have gone farther into the subject; and, struck with the general appearance of fungi in the disease, have ascribed it to these as the original cause…contenting themselves with having detected the proximate cause, they have not pursued the investigation, and endeavoured to trace the remote cause, that which produces the fungi themselves.”
McWilliam aimed to understand the conditions that allowed the initial defect. He described growing conditions for trees, harvesting methods, the chemistry of air, the importance of carbonic acid and ventilation, forest management, forestry law, and the economy of wood harvesting. McWilliam criticized some of Chapman’s 1817 conclusions but complimented others. He evaluated several methods of preventing rot.
McWilliam also referenced Parliamentary testimony about how long warships could last. He examined the timber demand for naval repairs, commercial shipbuilding, and building construction to estimate Great Britain’s total demand for oak. Like other writers, he was concerned that the rate of rot threatened Britain’s sovereign supply. If rot was not prevented, the Britain would run out of wood. The navy would collapse and so would the economy.
McWilliam was not important in other naval matters. This is another example of maintenace methods and ship life-cycle economics being examined by diverse authorities in the early 19th century. British History Online describes that McWilliam influenced the development of North Street in London, but little else was known about his life. Philip Temple wrote about McWilliam in Survey of London: Northern Clerkenwell and Pentonville.
1821 – Layman: The Pioneer, or, Strictures on Maritime Strength and Economy
William Layman served as a lieutenant under Admiral Horatio Nelson, then commanded two smaller ships. He lost his second command to the Spanish after drifting into Cadiz, for which he was court-martialled in spite of Nelson’s influence. His naval career was ended, and he turned to something like freelance consulting and authorship.
In his 1821 book, William Layman noted that rot had reduced the average ship life from 11 to only 7 years by 1793. He estimated that 31 million pounds sterling could be saved annually by extending hull life. To figure this cost, he included a cost of capital, the government interest payment needed to raise the money for frequent planned repair periods.
Layman’s payback model used contemporary maintenance cycles, which he described in detail. A ship would go through small repairs after three years. After five years, a larger “middling” repair package was twice the cost. In the 8th year, the ship would undergo the largest repair period, which cost four times the price of the small period. The cycle of repair periods at 3, 5, and 8 years with a cost ratio of 1:2:4 repeated two more times over a ship’s life. This was Layman’s base case, meant to predict the future maintenance costs of the existing fleet using maintenance practices that were common at the time.
Layman’s method of calculating ship lifecycle maintenance costs was very similar to the method Sutherland published in 1717. Both calculated life-cycle maintenance costs. Both assumed predictable maintenance cycles with alternating scope. Both authors proposed that investment in better initial quality would reduce the maintenance and replacement expenses over the course of two or three decades.
Layman proposed that a ship could be built without defects, so that it would last three times longer and not receive the first major repair until 25 years of service: “With only one-third the expenditure of timber, other materials, and workmanship, as only one-third the number of ships would require to be built.” (p 84)
Like 21st century reliability programs, Layman promised huge returns by eliminating the initial defect. Layman promised that he could supervise the building using methods from Bombay…if he were allowed to select timber “without interference.” Managing a major construction project “without interference” was unrealistic for several reasons. One was Britain’s entrenched design preference for native oak. The other reason was the military-industrial complex, the civil workforce and their votes, and the security implications of moving such a production capability to a colony.
Layman’s short work did not explain his method. His other writings show that he studied shipbuilding by the British East India Company. His 1813 book, Precursor to an Expose on Forest Trees, compared the durability of the East India Company ships to the navy’s. Layman used experiments to select the best methods to season British oak so that it nearly reached the performance of Indian teak. Like earlier authors, he advocated for building and storing ships under cover as part of this process.
Layman was knowledgeable of the history of naval construction in Britain. He was well-informed about trends in hull service life and value in the 18th century. He referred to the founding of a special construction organization in 1605, the naval inquiry of 1618 and the influence of Phineas Pett, the organizational impact of the civil war, and writing by Samual Pepys in 1688. He did not directly reference or give credit to Sutherland. Sutherland’s book was well-known, so Layman may have simply repeated Sutherland’s exercise. However, the maintenance cycles related by both authors seem to have reflected actual practice.
Layman’s entire discussion about reducing life-cycle maintenance costs was less than 20 pages long. His concerns for the nation and navy as a whole, and his experience as a navy captain led him to concern for the sailors. The first 65 of his 87 pages of his book contained his arguments against impressment, and for improved berthing, pay, and training. Layman recognized that life-cycle costs could be reduced, but that the organization had other ways to improve to best accomplish its national mission.
1821 – Knowles: An Inquiry Into The Means Which Have Been Taken To Preserve The British Navy, From The Earliest Period To The Present Time, Particularly From That Species Of Decay, Now Denominated Dry-Rot
John Knowles described how to build and manage a complex timber structure in a marine environment. Like Pering, Blackburn, and Bosquet, he discussed timber selection, harvesting, processing, chemical preservation, ventilation, and construction.
Three chapters examined methods of preventing rot and ventilating ships, especially in construction or when the ship was being stored. Knowles reviewed similar methods used in Venice, France, and Spain.
Knowles related preservation methods explored by Samuel Pepys. He cited Pepys’ 1690 memoir and his re-appointment in 1684 by Charles II specifically to solve the problem of preserving a relatively idle fleet. Knowles’ book has seven references to Pepys’ work including direct quotes, for example,
…the defects were attributed by the government “to the omission of the necessary and ordinary cautions used, for the preserving of new-built ships, divers of them appearing not to have been once graved, nor brought into dock since they were launched; their holds not cleared nor aired, but, for want of gratings and openings, their hatches and scuttles, suffered to heat and moulder, “till,” says Mr. Pepys, “I have with my own hands, gathered toad-stools growing in the most considerable of them as big as my fists.” (pg 92)
This is the same letter by J. R. Tanner’s 1899 seminal academic work on Pepys in the English Historical Review. Knowles quoted Pepys’ examination of rot in 1821, 78 years before the well-known academic history was published.
Knowles was studying Pepys’ naval letters before Pepys’ famous diary was decoded, and four years before it was published. Knowles likely had Pepys’ Memoirs, several of this Memoirs of the Rise and Progress of the Royal Navy. This semi-official history was published in 1806 by navy clerk Charles Derrick. Derrick’s history contained many references to Pepys’ work to restore the navy after a period of deferred maintenance. Knowles was not an academic historian, but the Chief Clerk of the Surveyor’s Office. By the time Knowles published in 1821, he was Secretary to the Committee of Surveyors. His book contained a four-page distribution list, so the work was distributed within the Admiralty. A written body of knowledge of preventive maintenance had survived in the same organization from 1686 to 1821.
Knowles became a Fellow of the Royal Society in 1821 because of his work on rot preservation and naval architecture. He worked closely with the noted naval architect Robert Seppings, who made important improvements in diagonal bracing and the use of iron in ship’s framing and beams.
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