The New York herald., 1876-09-13
THE WALSH cOFFERDAM.


AN IMPORTANT INVENTION SUCCESSFULLY
TEsTED-sUBMERsIoN OF THE GREAT PokT-
ABLE CoFFERDAM IN HARsIMUs cow, JER-
sEY CIrY-THB RIvKH BOTTOM LAID BARE III
DEEP wATER-AsroNIsHINo THE FISHES.
Yesterday afternoon a large party Of gentlemen,
mostly connected with public improvements and the
com transportation companies, but all inter-
ested in the subject Of Submarine engineering ~ ap-
Piled to docks, pers bridges, &C.. assembled at pier
49, North River, at the invitation OF Mr.. John e.
Walsh to witness the nrst public trial OF portable
coiierdam OF his invention. Among those present
Commissioner Salem H. Wales, President Of tho Dock
Department, md several OF the sub-oliciaIs;
Mr. Martin engineer OF the East Rivor
Bridge; Mr. worthen, civil engineer; Aessrs.
Macdonald G. J. Thebaud NJ. J. McCafrey and
Gericke besides several representatives OF the presS
The steamer Seth Low was chartered 10 convey tho
party to where the great ark-like coherdam was
moored and by O'Clock P. NJ the deck Of tho novel
vessel II such be called, seeing that she has
bottom was covered with interested examiners OF her
peculiar construction.
Tho coaerdam "Centennial" Is a huge boxsidcd
structure with gates hung at either end OF the side
walls which meet at point, making her sharp ended
and therefore very manageable while being towed
from point to point around the harbor The sidos and
ends enclose water space of 900 square feet,
with solid perpendicular walls Of timber which
are fifteen feet wide and hollow the spaces
within them being arranged in compartments
for pumping machinery and for the water
ballast that is employed in sinking the conerdain The
structure therefore, does float its bottom for
has whole, but ON the bottom of its side and
end box walls which fitted with kees for the double
purpose OF balancing the dam when 1t Is in sections
and OF rendering perfectly steady when it first rests
the mud The kees cut deeply into tho
soft mud and thus make perfectly right joint
between tho conerdam wall bottom and the ground
which it rests.
An idea OF its application to deep water building will
be better conveyed by brief of Yesterdays
trial than by special description Of the different parts
OF the structure
On mounting tho side Of the dam which was then
floating IN about twenty feet Of water, tho visitor
found himself narrow deckway which ex-
tended ali around n vast VOL formed bv tho on.
closing walls. This the top OF the wall, the
interior OF which divided into water and air tight
chambers engine rooms, &c The enclosed space rep
resented The sr> OF proposed deep water foundation.
the object Of the whole coierdam being to render that
site dry while the river outside rose and fell IN level
with the tidal flow and ebb
AT signal from Mr.. Walsh tho valves of the pipes
communicating between the interior and exterior OF
the dam walls were opened and tho chambers rapidly
filed causing the whole cofIcrdam to sink gradually
and without the least apparent downward motion as
the weight OF the water increased When the lcvos in
sldc ana outside the walls equal, the valves
closed ana additional water pumped into the wall
chambers until they nearly filed to the top TINS
increased weight caused the coerdam to sink still fur.
thcr until 1t finally rested and mbedded itself deeply
into the muddy bottom
1t anchored fast by its own weight, and the
full power Of the pumps was turned the water
closed Ia the interior well before described The level
OF this body of water soon decreased and as 1t Tell
lower and lower with each stroke OF the powerful
pumps, the great dam settled deeper still its bed Of
mud Soon the agitation among tho nsh imprisoned in
this large enclosure begun to attract attention. and
everybody knew that the bottom would show
sclt True enough duh outline OF mud ridges FOL.
lowed quickly by the ridges themselves successfully
appeared, aud the interior space began to divide itself
into small pools of water which drained toward the
pump wells
Now the svor-sided fishes began to grow terribly
alarmed They were experiencing an entirely now
sensation The dark, muddy depths in which they had
calmly reposed suddenly became as bright as the sha.
lowest pool The crabs sdled away the bare mud,
made desperate efforts to gam watery but hosptable
corner wherein TO hide themselves, and the eels slid
about IN an exstacy OF fright and performed somer-
saus with desperate energy tho water slowly
drained away. The bed OF the river was bare aud two
workmen engaged in attending to the foot valves Of
the pumps walked about in safety where u short time
bet there had been fect of water The
greatest curiosity displayed by the engineer visit
orsas 10 the ability OF the dam to exclude the water
that tended to enter the enclosure by under leakage
used, not drop Of water entered the large
dry space at any point Both Commissioner Wales
and Mr. Worhen expressed themselves perfectly
satisfied with the trai and remarked that the nven
tor, Mr.. Walsh, deserving OF the highest
In designing and building such structure.
Mr. Wales said further that II the Golfer dam
satisfactorily proved IN practical work to be moro
economical than the present system OF laying founda
tions by the Dock Department, the city should Of
necessity Ton that account alone Mr.. Worthen,
who is an engineer OF great emnence, expressed him.
sell as fully confident as TO the practical utility OF tho
new Golfer dam and warmly congratulated Mr.. Walsh
on his success. The dam raised again by the ad-
mission OF water into the interior, working space,
through sluice ways and then pumping out the wall
chambers after which the huge vessel foated agais
without perceptible motion. Taken experiments
trial. the test of Yesterday proves the thorough
of the workmanship this unique structure and
the with which II can be applied to almost every
kind OF submarine building in moderately deep water.
AT O'Clock NJ. the visitors, who had been hospit
ably entertained by Mr. Walsh board tho Centennial
returned TO Now York the Seth Low.