The evening world., 1890-05-29
DIGGING OUT SHELL Reef.
Plans to Remove a Dangerous
East River Obstruction.
rhe Channel TO BE DredGed to n Uni-
form Depth OF Eighteen Feet.

The bold mariners who navigate all
kinds OF craft through the turbulent
winters Of the East River will hcave great
signs of relief when they learn that that
dangerous obstruction to navigation
known as Shell Reef will soon DO re-
moved by the Government. Surveys
have been made. and estimates Of the
cost of removal are already before the
House of Representative.
Shell Reef hns mnde the East River from
Broome street to Twenty-third street a
SPOT TO be carefully avoided by pilots in
charge of deep-draught vessels. During
low tides large steamers and sailing yes
sells have been obliged to hug the eastern
side of the channel In passing up or down
the river. This IL done to avoid the
dangerous west shore.
The reef begins at the foot Of Broome
street, and gradually extends outward
until q maximum width Of /. lU0 feet is OBJ
tGined. Then it slopes in sharply 10
Twenty-third street, where II ends. AL
though the whole shoal Is commonly
called Shell Reef, there il only one spot
really entitled TO that name. That Ia OPP
pusite Tenth street, where | 100 feet from
shore a spur OF solid sharp. pointed rock
protrudes from the bottom until ut low
tide only nine feet of water cover il.
The whole Slot IN 4, 100 feet long. The
dangerous point IN 276 feet from the
Tenth street pier and 1880 feet from the
Brooklyn shore opposite.
The removal OF this enormous ledge Of
rock - bound TO be expensive and dali
Rerous. just at this point the tide runs
like n mill race, and divers will only be
b TO work Mt slack water.
The work of surveying and boring was
begun July q last. 1he work was done
In a thorough manner by Lieut.. Col. G..
i. Gillespie, Chief ufthe Army Corps Of
Engineers, and Assistant Engineer g..
w. Kuehule, ably assisted by IA party from
the Hydrogrnphic Otfics under the dirCc-
ton of Mr.. j. JOlInstone.
Their observations we're completed
Sent. "a. but frequent borings were made
during the following three months.
IL might be interesting Mt this point
10 tell how the borings are made. A
scow belonging To the Hell Gate plant
was anchored over the pot to be bored
by four anchors, sent down IN n many
different directions at slack water. A
graduated pipe two inches III diameter
connected with a force pump by a rubber
hose. is sent down vertically from the
Gov until II touches the bottom. A
stream of water thrown under high pres.
49, ~ - NhNA AcASNNA hbNh NIG III
III burrows a way for the pipe, which
gradually sinks until il is stopped by
bOuldefs, or solid rock, or some material
too hard for the stream ~ penetrate.
The shOal. as developed by the bor-
fngs, shows that it consists of mud, sand
aud clay, through which are outlined
huge bOuldcrs. There is little or no mai.
cation of solid rock except at tine reef
proper, Oh Tenth street, and even there
1t is not certa.n that the jet MAS NOT
stopped by the boulders rather than bed
rock.
Prom Thirteenth 10 T,Tenty.tbird
Street the report says, there are mud and
sand. This material will be difficult to
remove by means OF the ,lrcdgu buckets.
because there is no telling where n
boulder may be encountered that will
emRsl the iron mouth into smithereens.
IL Id believed. however, that much Of tins
material will be swept away by the swift
tres when The dredges make a lrcak IN
It. The depth to which IL is proposed Ia
deepen the CHANNEL is eighteen feet.
Col, GILLESPIE saws that To- eXcayate or
remove any ruck which would not eiect
thiA deldh would be worse than useless.
C~olnhieIce. he says. would he we'll salts
nsu with HAT depth for many years TO
come.
20 dredgc this averale depth from
bToome street 10 T~wenty-thirl street
you'll cost according To the estimates,
SHbI'5A. This IOss not seem 10 be Ia
NerL large sum for such an important
Sork. Indeed, when the danger aud ihe
losses that have been OcCasioued hy tie
IA. OF these r. els are cousldoTcd.
tbs comparatively nothing.
Col. Gillespie, though, says one tllur
IN his report that nautical men will Ia
sure TO pick up aud discuss. lie says THAI
eolnlneree will be satisfied with au eisl,.
toen-foot depth for q numl eF OF yFgIsto
conn. But for how long: naylgutrTs
Nill ask. Vessels nre beng built larger
snd deeper every year. aud if Uuty a
depth OF eighteen feet is attained Lv Ills
proposed work IL may lie neces slry To-
future. "'"t
With an eye TO this future Col. Giles
PIE has prepared estimates for a deeper
dfedgng, aud IA following table has been
seat Ia With the report;
VspA. g,.fua