Coppering and caulking – a mixed blessing?

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    Malcolm Lewis

    When coppering of ships began in earnest in the 1780’s it must have been a mixed blessing for those required to maintain both naval and merchant vessels. Whilst the problem of fouling was greatly improved by copper plating the hull below the waterline, wooden ships would have continued to leak at the seams beneath the copper.
    No matter how good the caulking of the outer planking leaks were caused by the movement of the timbers within a very short time. In 1760 HMS Thunderer had to be re-caulked on arrival at Gibraltar after her maiden voyage. (Building the Wooden Fighting Ship-Dodds & Moore)
    HMS Bellona was first coppered in 1780 and was subsequently “repaired” or re-coppered fourteen times up until 1811. (The 74-Gun Ship Bellona-Lavery)
    Would this have been because of damage to the copper or because ships were leaking beneath the copper and needed to have the copper removed to re-caulk the outer planking?
    Caulking teams from the ship’s crew when in commission were constantly at work on planking above the waterline. Would they be repairing leaks below the water line by caulking the inner planking? This would presumably mean that sea water was entering the confined spaces between the outer and the inner planking. Apart from causing rot would this additional weight of water have affected the handling of the vessel?
    Malcolm Lewis

    Wayne Tripp

    You ask some interesting questions, Malcolm. The amount of water entering the ship would, if not removed, have created serious handling and stability issues. The pumps (of various designs over the years) were, in general, able to easily keep up with the leakage on a daily use (sometimes longer) basis.

    A large part of the need for re-coppering related to the aging of the copper. I need to check the source again (I actually think it was in MM), but there was a finite time (which far exceeded the 2 or 3 months of the earlier treatment methods) before copper plating lost its effectiveness and needed to be replaced. It was also subject to damage from anchor contact, grounding, or other contacts. The effectiveness depended on complete protection – any breach resulted in rapid development of leaks and fouling.

    Sam Willis

    I think that one of the most important points about coppering that is so often ignored is that ships in a fleet could have both good and bad copper – which affected their performance in different ways. It is therefore unhelpful just to compare coppered fleets with uncoppered. The American Revolution offers the most frequent examples of this, particularly when British ships with old copper in the West Indies came up against uncoppered – but fresh – ships from France, and found that the French ships completely outsailed them.

    Nicholas Blake

    In the first decade or so, there was a great variation in the quality of the copper, the weight of copper, the method of application, and what if anything was laid between the copper and the wood.

    In 1779 for example copper was applied thus:
    The ships’ bottoms to be covered first with a thick coat of paper in the following manner:
    1. the bottom is to be paid with a thin coat of warm tar
    2. the paper is dipped in hot but not boiling tar, then applied overlapping and tacked on
    3. the copper sheets are painted with white lead on the insides, and where they are nailed at the edges, strips of cartridge paper 1.5in wide are laid under them
    4. nails to be placed about 3in apart
    5. the sheets of copper are laid from aft forwards, so that they overlap towards the after part of the ship
    6. the workmen who punch the holes are to be followed closely by those who drive the nails
    ADM 106/2508, 8 Jan 1779, no. 793
    Then this was changed almost at once:
    ADM 106/2508, 17 Mar 1779, no. 828, directs that the insides be painted three times; 28 Oct 1779, no. 915, that the paper is thinner than before; 13 Jun 1780, no. 988, brown paper replaced by prepared paper, and Dawson’s mixture to be added to the tar

    This was revised again in 1783:
    ADM 106/2509, 31 Dec 1783, no. 254, provides new instructions:
    1. for ships’ bottoms, copper sheets of 32oz to the foot square to be used as far aft as the extreme breadth and for the three upper strakes fore and aft, elsewhere 28oz to the foot square to be used: the copper to be continued not less than 16in above the load water line
    2. sheathing paper of 19oz to the sheet as directed on 4 Jun 1783 to be used for all ships, dipped in and impregnated with tar immediately before use, overlapping and beaten smooth without ridges
    3. the copper under the braces and pintles to be 16oz
    4. false keels to be coppered on the under side, but not for ships of the line, which require a purchase to heave them in and out of dock, and therefore must be filled with brads and nails only
    5. each contractor’s copper to be used as much as possible by itself, so that when the ships are repairing its quality can be determined and any imposition on the public reported
    6. dockyards are to take care that their demands fall within the limits of 40 tons, 15 of which to be lacquered.

    From 1795, copper sheets to be marked with the contractor’s name (presumably for this reason); Captain Keats complained to the Admiralty that the Superb sails ‘wretchedly ill, which we attribute to the Foul & Defective Copper — she was originally sheathed 4 Years ago, with Copper of very bad quality and which, if I am rightly informed had been several weeks under water.’ ADM 80/141, out-letters f. 19.

    Ships were also recoppered because the sheathing was removed to inspect for damage.

    Later there was discussion about the manufacture of the copper: 19 July 1806: ‘there being reason to apprehend that the foulings contracted by the copper on the bottom of His Majesty’s ships (contrary to what is known to have taken place when the practice of coppering ships was first introduced in the navy) and which has of late years so much increased as to become an evil of a serious nature, may be occasioned by the degree of hardness given to the sheet copper, owing to which the attrition necessary to keep it bright, in passing through the water, is prevented’, three sloops and a frigate are to be coppered at Portsmouth, on one side with the softest copper that can be manufactured and on the other side with the hardest copper. ADM 2/310 f 273-4

    There was also controversy about the correct metal for the nails. Iron was discounted quite quickly, but whether copper or ‘mixed-metal’ was better continued: ADM 106/2517, no. 311, 17 May 1806 attributes the loss of the copper of the Superb and Thunderer to ‘the smallness and smoothness of the Nails with which it is put on’, and directs Deptford, Woolwich, and Chatham to use mixed-metal nails henceforth, and ADM 106/2517, no. 319, 30 May 1806, directs the home yards to examine the short copper nails and add mixed-metal nails as needed. There were also instructions about how the nails were made and how they were driven home.

    Frank Scott

    I have only sailed in one vessel that was coppered. This was the Ketch rigged Brixham trawler Kenya Jacaranda, way back in the summer of 1967. She was not in a great state, having only done very short trips for the previous decade or so, and we had a lot of work on the rig to make her fit to sail. The following year, en route from Harwich to Kristiansand, during a Tall Ships’ Race, she experienced heavy weather which caused her to leak so badly that for a time the crew had to resort to a bucket chain. As a result she was slipped in Norway, and when the shipyard took off some of her copper they found that she had not been re-caulked for many years. The consensus was that in fair weather it was the coppering that had kept (most of) the water out, but once she started to work in that heavy weather she had ‘opened up like a basket’.

    Incidentally, the Kenya Jacaranda, which was built in 1923, has now reverted to her original name Torbay Lass and is awaiting restoration.

    All wooden vessels leak, and thus require good bilge pumps. However, when that was the norm, seafarers simply accepted it, and provided that the pumps were run regularly, and the vessel was maintained in reasonable condition, this was not a serious problem.
    To answer a few specific points:
    1. The weight of water that came in normal condition would not cause any handling problems. Of course, if pumps failed, and you lost control of the water level, this was a very different matter. This was most recently shown when the Bounty (built for the 1960 film) was lost when she encountered Hurricane Sandy in October 2012. See US NTSB, Marine Accident Brief 14-03: Sinking of Tall Ship Bounty (Washington, 2014)
    2. Caulking of the hull is done from outside, when on a slipway or in a dry dock, and in general coppering helps to keep the caulking in place. In the past, whatever work the carpenters team did from inside the ship, was not made any more difficult by the coppering.
    3. Mention should be made of Teredo navalis, the infamous shipworm. Prior to the development of modern anti-fouling, coppering was the only practical means of keeping these destructive beasts at bay. As I write I have in front of me a piece of hull timber recovered from a shipwreck by the late Peter Throckmorton (1928-90) that is so riddled with Teredo holes that it resembles Gruyere cheese.

    Frank Scott

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