Ottomans seem to have been aware that the copper-sheathing
technique, when it first appeared in Europe in the second half of the
eighteenth century, had offered significant advantages. Among them were
protection from wood-eating worm; the creation of a surface on which external
weed and shellfish could not grow; an increase in sailing speed that not only
reduced voyage times but made navigation easier, since if a vessel could move
in light winds it was less liable to drift on ocean current; the applicability
of copper sheathing to any shape or size of hull; providing an outer skin of
copper protecting the hull to some extent; holding caulking materials in
position; and reducing maintenance costs between voyages.
The disadvantages, such as high material and application
costs, the risk of galvanic action and the deterioration of iron fastenings,
and the fact that a coppered vessel could not be grounded in harbour without
considerable risk to the sheathing and thus was restricted to harbours with
water at all tides, could not prevent the Ottomans from adopting this
technology. However, some of these disadvantages were unknown to them
initially. The Ottomans learned about these as a result of prolonged naval
experiences. Thanks to academic work from the 1950s onwards, the nature, type
and properties of the molluscs and crustaceans hazardous to the timbers in the
seas surrounding Turkey have been identified.
There is considerable evidence indicating the existence and
application of this technology in ships built specifically in the reign of
Sultan Selim III. There were at least 40 ships that were sheathed with copper
between the years 1789 and 1802, mostly galleons, frigates and corvettes. This
figure must have been higher considering the imperial edict issued in 1795–96.
Indeed, it shows that the application of copper sheathing to ships proved to
bear good results and it led the Sultan to order the authorities to try hard to
outfit the remaining ships using this technology. Firmans ordering the copper
sheathing of ships were issued repeatedly. For instance, in a firman dated
1795–96, copper sheathing and painting were ordered for river ships (ince
donanma gemileri) when they were at anchor. Following the copper sheathing of
Arslan- i Bahrî and fiehbâz-i Bahrî, the same application was ordered in 1795
for Pertev-i Nusret, Ejder-i Bahrî, Âsâr-i Nusret, Bahr-i Zafer and another
three-decked galleon under construction. The estimate amount of raw copper
required for all five ships was around 60,000 kiyyes. Since this process
required casting very thin copper sheets processed twice, the copper coming
from Gümüşhane
would not be suitable; instead, that from Kastamonu or Ergani would be needed.
It seems that copper-sheathing technology was limited to warships at the time.
Mahmut Raif Efendi described copper sheathing in his account
as well. He wrote that all the shipmen shared the idea that copper sheathing
was the best way to protect ships. He noted that three ships, a three-decker of
67 zirâ and six kâne, a frigate of 55 zirâ, a corvette of 37 zirâ, and a boat
(filika) for the Sultan were launched in a single day, which was something
previously unseen. The year before (1797), all of them had been sheathed with
copper, and more ships were to be sheathed in 1798. Therefore, it would not be
misleading to regard most of the ships, especially warships constructed after
1795–96, copper-sheathed. Also, the prize ships and the ones received as
presents would increase the number of shipped that were copper-clad at the
time.
The earliest document found during this study indicating the
Ottomans’ application of the copper-sheathing technique dates back to
1792–93141 In that year, the Ottoman government ordered the copper sheathing of
a new galleon, and copper merchants were ordered to prepare copper planks on
certain models. Once the copper sellers saw the model, they declared that the
production of the model was different and would be more difficult than the one
they had used previously, and therefore it would require more labour and money.
Then the merchants were presented with lumps of unrefined copper for the
production of the copper plates for the sheathing of the galleon in question.
They were given 55 akçes per vukiyye, whereas it had been 35 akçes in the past.
However, since the new technique required the use of copper nails, which were
expensive, they found a solution by producing a new type of nail made of raw
copper and zinc (rûy-i mâye) mixed in equal proportions. In order to test the
efficiency of the new nail, they first produced five or ten test nails. After
applying them to the copper plates, the authorities were convinced that the new
method would work, so copper merchants were commissioned to cast this mixture
in return for 50 akçes per vukiyye. It is noteworthy that such a decision was
taken with the collaboration of the port commander (liman reisi), the chief
architect (baflmimar), the chief augerer of the naval arsenal (tersane
burgucubaşisi)
and copper merchants (bakirci esnafi). The raw materials were provided by the state
from the mahzen-i sürb.
On 30 August 1795, 5,000 vuk›yyes of raw copper were
demanded urgently from the Darphâne-i Âmire. For the copper sheathing of a
three-decked galleon under construction at the naval arsenal, 10,000 vukiyyes
of raw copper were required on 20 October 1801. Since there was not enough
copper at the mahzen-i sürb, it was provided by the Darphâne-i Âmire,
two-thirds of it low quality and one-third high quality. The cost, 6,666.5 kuruş,
was met by the seferiyye akçesi.
It seems that copper sheathing caused further changes in the
structure of materials used in the construction of ships. It was noted on 14
September 1796 that it was a tradition that bearing pintles (inecikler) mounted
on the rudders of the imperial galleons were made of iron. However, this
traditional application was changed with an imperial edict ordering the
introduction of copper sheathing of the ships constructed at the Tersâne-i Âmire
and other sites outside of Istanbul. From then on, the former iron bearing
pintles of the sheathed ships were replaced by ones made of bronze (tunç). Four
vukiyyes of tin (kali), 32 vukiyyes of raw copper (nühâs-› hâm) and 64 vukiyyes
of zinc ferment or alloy (rûy-i maye) were needed for every 100 vukiyyes of
bronze bearing pintles. Also, one k›yye of hark-i nâr was required for every
ten vukiyyes of the product. It seems that new regulations were applied to a
new frigate under construction on Limni on the same date. It was declared that
eight bearing pintles for rudders (465 vukiyyes) would be produced by Dimitri,
the chief founder at the Tersâne-i Âmire on 3 September 1796. The Ottoman
authorities continued the copper-sheathing applications in the following years.
On 3 January 1806, 30,000 kiyyes of copper were demanded from the Darphâne-i
Âmire for the re-sheathing of five naval ships with copper plates (nühas tahta)
and the repair of the copper elements of some other ships at the naval arsenal.
