Environmental Engineering Reference
In-Depth Information
Box 9.4
Timber Required to Build Large Naval Sailships
An original French design of large (about 54 m long at the gun deck), two-decked
battleships carrying 74 guns and crewed by up to 750 men became the dominant
class of naval sailing vessels during the late eighteenth and early nineteenth century:
the British Royal Navy had eventually commissioned nearly 150 of them (Watts 1905;
Curtis 1919). A typical 74-gun ship required about 3,700 loads of timber (a load
being equal to 1.4 m
3
), including nearly 2,000 loads of compass, or curved grain,
wood. With
Quercus robur
density (air-dried, seasoned wood) at 650 kg/m
3
, the entire
ship consumed about 3,400 t of wood. The total mass of timber varied due to dif-
ferences in the thickness of planking (the heaviest one could be in excess of 10 cm)
and in the construction of keels, decks and masts (the latter usually of lighter straight
pine with average air-dry density of less than 400 kg/m
3
), on the vessel's size (gun
deck lengths of 74s varied between about 50 and 56 m) and on the mixture of wood
species used.
The total mass of wood used to build a 74-gun ship ranged from less than 3,000 t
to nearly 4,000 t. Larger ships needed less material when measured in wood loads per
gun: for the largest 120-gun vessels the rate was as low as 40 loads per gun, for 74-gun
vessels it was around 50, and for frigates (22 guns) it was as much as 100 loads per
gun. In absolute terms the highest totals (such as for the 121-gun
Victoria
) were in
excess of 6,000 loads, or as much as about 5,500 t of oak wood. But more timber had
to be ordered because 30%-40% of the material delivered to a shipyard ended up as
waste. Linebaugh (1993) showed that the gap was often much larger: chips, pieces of
wood no more than 90 cm long, could be taken offsite by workers, to be used as fuel
or timber for their houses and furniture or sold for proi t. As a result, up to 60% of
all timber delivered to a shipyard to build a 74-gun ship ended up elsewhere.
be burned, but only the mature trees of a few oak species (often also from specii c
areas) were considered the best choice for ship timber.
We also have a comprehensive estimate of the Royal Navy's wood requirements
during the last decades of the wooden ship era. In 1810, the l eet's tonnage was
some 800,000 tons, and with roughly 1.5 tons of timber needed per ton, it took
approximately 1.2 million loads, or 1.1 Mt if all of it were oak and less than 1 Mt
if it were a mixture of hard- and softwood species dominated by oak. The average
lifetime of naval ships was about 30 years, but substantial repairs were needed after
15 years. When these realities are taken into account, the annual rate of timber
consumption for new construction and repairs prorated to about 110,000 loads, or
at least 90,000 t of timber a year.
After the age of large wooden ships ended (steel became the top choice by the
1880s), wood continued to be used for building smaller vessels, boats, and yachts
