The Sun.
London, England, 1826-07-24 00:00:00

THE DRY ROT IN SHIPS.

We find, in the Second Number of a recently establish-
ed periodical publication, entitled, " Papers on Naval
Architecture and other Subjects connected with Naval
Science," some sensible remarks on the soundness of the
ships of his Majesty's navy, from which we extract a few
observations on " The Disease in Timber called the Dry
Rot," about which so much noise was made in a Session
of the late Parliament.

It is a prevalent but an erroneous opinion, (says the
writer), that a new and most destructive disease has at-
tacked our ships, known by the alarming epithet, the
" dry rot." This name is commonly given to that species
of rottenness, to which timber is subject, which is distin-
guished by the growth of fungus: It appears that this
term was not inserted in any official document earlier than
the year 1808. In the year 1811, when the Queen Char-
lotte, of 100 guns, was discovered to be in a state of pre-
mature decay, this term was more generally introduced;
since which period it has been too indiscrimately applied,
and its effects greatly exaggerated. This disease has,
however, existed, although known by different names, and
its destructive effects have been felt and regretted from
most remote periods of history.
The paper proceeds to trace the causes of the disease,
and then gives a summary of the precautions taken in the
dock-yards for its prevention and removal; which is most
worthy of attention, as it shows in a few words that there
are grounds for the completest confidence in the soundness
and efficiency of our navy.
The numerous nostrums which have been proposed for
the prevention and cure of the dry rot have tended much
more to give a false impression of the prevalence of this
disease than to remove or diminish it. Mr. Knowles, of

the Navy Office, in his work entitled, " An Inquiry into
the Means whicci have been taken to preserve the British
Navy," has given an account of different trials which have
been made to prevent or cure the dry rot, with the results
of the experiments. This work shows that the Navy
Board has been always desirous of trying the proposed
methods, when they could in any way be shown to possess
any reasonable appearance of success.
The methods which are at present adopted in his Ma-
jesty's Dock-yards, for the preservation of timber, are such
as have been suggested by an examination of its nature,
and the.circumstafices in which it is placed in ships,
and which have been proved by experience to have
been well calculated to produce this desirable effect.—
The principal methods are seasoning the timber under
roofs; iintnerion in salt water ; taking off the sap-wood
from the tital)er wit •it tweti; covering the !Itit face%
of the timber with mineral tar and paint, particular at-
tention being paid to all the surfaces which come in contact
with each other; and the injection of a mixture of vege-
table tar and whitening into ships' bottoms. Placing tim-
ber under roofs, the logs being kept apart from each
other, is found to be an excellent method of seasoning
timber, by admitting a free circulation of air without an
exposure to the rain. The immersion of timber in water
is found to be an expeditious method of drawing out the
juices of the weed ; and salt water is preferable to fresh
water for this purpose, on account of the anti-putrescent
property of salt, which, though less effective on vegetable
than animal matter, is useful in checking the decay of
timber. Taking off the sap-wood, which speedily becomes
rotten, prevents the communication of the decay to the
adjoining heart-wood. Covering the surfaces of timber'
with mineral tar or paint keeps the timber from being rent
by the air, and also prevents the seed of the fungus, which
may be in the outer lamina of the timber, from vegetating
by the exclusion of atmospheric air from it. The seed
also which may be deposited from the gases on the stir-.
faces of the mineral tar and paint will not vegetate. It is
also particularly useful, when two kinds of timber arc
brought together, by preventing the fermentation which'
would arise from the union of different vegetable princi-,
pies. The injection of the tar and whitening into the
ships' bottoms has been found.to be of very great benefit
in preserving the timbers, by its effectually preventing the
growth of the fungus; the openings between the timbers,
which would otherwise be imperfectly filled, and the rents
in the timbers, in which places the fungus would be most
likely to vegetate, being, by this means, completely filled,
the necessary attendant on vegetation is excluded. It
probable that the great advantage of the injection of tar,
&c. into the' nterstices between the timbers, and in the
rents of the wood, is not yet fully known. In addition
to these preventives, the ships are built and repaired under
roofs, which prevent the rain from settling in the rents
of the timbers and the openings between then,.
In his Majesty's ships in ordinary, particular attention
has also been paid to preserve them, from decay, by put-
ting temporary roofs over them, taking down part of the
bulk-heads in the hold, and leaving out strakes in the
deck, and leaving openings in the truss-work between the
ports, to promote a free circulation of air through them.
It may be remarked, however, that a. free current of air
through the ships, which is of very great advantage in pre
venting decay, is attended with the disadvantage of
causing the timber U. shrink, which is injurious to the
strength of the fabric, by destroying, in some degree, the
benefit of fitting the pieces of work closely together, tech-
nically called Paying well,', to:give stiffness to the parts
of a ship, and thereby brings a great strain on the fasten-
ings. The maximum of advantage is therefore to be ob-
tained by giving such a circulation of air as may be suM.
cient to prevent decay, without causing the timber to shrink
too much. Experience is tending fast to ascertain the ex-
tent to which this principle may be carried with the
greatest advantage to the service.
The result of the examination of the Bellerophon is next
themselves
;-..the
v ship, moreover, remaining open
mentioned, when, to the discomfiture of the dry-rot alarm-
ists, the opinion of the naval officers, shipwright officers,
and carpenters of the Navy, was unanimous as to the ex-
cellency of her state
for several weeks, that all whos fth
ow same.might, The
article by personal
inspection, satisfy helneie
concludes--
It might be thought fair to infer, that if such is the state
of a ship which was particularly selected as ft proof of the
decay of the British
'
Navy, tha whole of his Majesty's
ships might be considered equally sound.
inn disce
°nines? But this would be claiming too much. It is
enoughto say that the strict examination of this ship and
others which were stated to be rotten, with the constant
examination of all the ships in the navy, fully proves their
very high state of preservation. It is enough to know
that all that can be done for their preservation is done, and
that the attention given to them is productive of the most
satisfactory results,