The New York herald., 1868-05-08
HE'LL GATE.
Report Of General Newton Touching the he'
movaI Of the Distractions In the Channel.

Congress having been asked 10 appropria'o 'iio
sum OF $685. 900 (now included IN the General Appro
pration bilD for the purpose of commencing inc
work Of removing the Instructions at Hell Gate and
improving the channel there, the following report
setting forth the precise extent and character OF the
work required to be performed to accomplish tins
object, will prove OF interest at the present ume
Having been assigned In July, 1855, to the duty OF
examining He'll Gate, and instructed TO make
such examination with the view or Hs
Improvement for the purposes OF navlga-
ton and sufficiently in detail to present
plan and estimate for the necessary operations,
General Newton of the United States Engineer Corps
in January 1867 submitted to the Secretary Of War
the result OF his abors in report follows Glanc-
ing at the reports Of his predecessors in this labor
Lieutenant Commanding G. II. Davis, assistant In the
Coast Survey, in February 1s4s; Lieutenant Com
manding d. D. Porter (now Admiral Porter, United
States Navy, in October Of the same year. and Major
Fraser, of the Engineers, In october, ls52-ah OF
which urged the necessity Of extensive operations
the report proceeds:-During the present season
surveys and examinations Of Hallets Point Scay
rock, the Frying Pan and Pot rock have peen
made, and the results given In the sketches sent
herewith. An examination was likewise made
by divers of the surface OF Pot rock
and Frying Pan, principally with view OF ascertain
ing the feasibility OF blasting by placing the charges
been elected, the indications that some of the
blasting necessary to be done can be effected by
simply placing the charge In contact with the rock
WORKS Projected
This portion of the subject has been frequently
discussed by officers Of distinguished ability, whose
reports are published, that little further remains to
be said. 1t is agreed that certain rocks IN
Ways Wa 0'He reef Shell Drake and and Others nearer
shore-viz., the rock or Negro Point those near
with portions of Hallet's Point and OF Scay rock
should be removed. Sea walls have been likewise
recommended to be built on the Gridlron Hogs Back
and on the Bread and Cheese and stone beacon to
be placed Rylander's reef To the rocks TO be re-
moved may be added the Heetap rocks, situated or
compel vessels to make such circuit as to endanger
their safe passage past Rylander's reef.
Concerning these rocks, HeeltapS, General Newton
says there is room for doubt as whether they exist
or not No sOundings made In the present survey
have resulted in finding them; but as they are marked
in former charts until it clearly established that
they are non est they are included In the oDstruc-
tiOns.
probably be added one upon Kylanders reef and
another along the seventeen feet curve OF Great MILL
sage and sheer of vessels. The great reefs In the
middle Of the pass-FOod rock, Negro Head the Grid
noticed in any scheme OF Improvement notwith,
standing they form the great obstacle to the pass OF
Hell Gate being converted into highway lor com
merce In the existing state Of the art OF removing
rocks under water the imagination was appalled, at
the notion even OF meddling with such masses The
middle channel ls narrow and Is rendered dangerous
by the projection Of Negro Head into It's lower outlet
The least Improvement that can be recommended In
this report should include Negro Head and the in
crease OF the width of this channel TO about $40 feet
Estimates are submitted for there projects.
The first includes the removal Of all the r. rocks cSs
mentioned at the beginning Of this division or the
report with the construction OF the sea walls and
likewise provides for the Improvement Of the middle
channel and the removal Of Negro Head.
The second includes the cost likewise OF the re-
moval OF that part Of the middle reef known as
Gridiron, thus throwing the middle channel into one.
The third includes the smaller rocks and the sea
walls and makes no provision for improving wing the the
With every Improvement Of Hell Gate the number
OF vessels passing through will increase and the me-
cessity for further room Will become more apparent
He'll Gate now washes with its waters the corporate
poron 0' Of t the Busy harbor New and
then viii arise demand for Improvement to
been enter entertained The uncertainty and slowness
attending blasting under water has had the effect OF
Hell Gate to which the Importance Of the improve.
ment Is really entitled, and II Is believed as soon as
the work can be pushed In regular manner subject
TO fixed laws OF calculation like blasting on land,
that the extent OF Improvement needed for the inter-
ess OF commerce will be the sole limit to public effort
manded, now and for the future, Is problem which
more properly belongs for solution TO those repre-
to their more perfect acquaintance with its wants and
capacity This report does not prescribe these linn
its, but the estimates, tables and other information
here furnished will enable any one to calculate the
expense Of projects different from those formally set
forth.
THE MODE OF CONDUCTING OPERATIONS.
project Is presented In the report simply as a
basis for calculation which consists In first prepar
ing he surface OF the rocks for Interior operations by
charges placed in position by divers until the rock is
reduced to a more uniform surface. Then TO blast
the rock by Introducing charges into drill holes made
for the purpose ana to remove the debris by divers
| The current, which has maximum velocity OF $50
little over two hours per day. during and about the
time OF slack water and hence the time and expense
unless some means OF sheldingthe divers and opera
tors from the force OF the current can be DEVISED
would prove O serious objection. Even II the per-
sons using the drills were protected from the current
the delay incident to this mode Of operations would
be considerable; but II the drilling were conducted
from the surface OF platform above the water the
same results would be reached as ON dry land. TO
avoid the interference OF the currents with the drills
these may be made to work In hollow iron cylinders
reaching from the platform to the rock This pro-
Ject as well as means likewise submitted OF remov
Ing the rock, is, however, General Newton says,
merely hypothetical, to show that the work could
some respects be that mode used in case the i'm.
provements ordered to be made as Ii suggested
n another part OF the report
DATA FOR THE ESTIMATE.
The rock In the samples obtained contains an ex
cess OF mica, making IL soft to the drill. The drill Is
supposed To bore seven feet o day, though 1t may
average ten feet Tie estimated cost OF drilling In.
cludes mooring and arranging the platform, services
steel expended, services Of engineer and fireman,
coal used in the snithing and for the engine, SER
| vices Of divers In arranging the supports OF the
platform and placing the drilling tubes, labor OF
unmoorIng platform, &c Estimated cost per linear
foot s4. The cost Of each charge includes the
estimated cost Of drilling the rock, OF the canister
and charge, labor OF divers in placing the charge,
services OF the operator and boats crew In firing,
expense Of wire, &C. Small charges are first placed
III the holes and split up the rock larger charges
introduced into the crevices and seams thus formed,
and complete the work Of breaking up the mass.
Estimate for so ID. charge OF gunpowder.....s45 so
Est innate for $50 lb. charge OF gunpowder... al rs
Estimate for ID. charge OF ntro-gycerine. 43 6s
Estimate for 10 ID. charge OF ntrogycerine. SO 80
Estimate for 3l113 lb. charge Of nitro gycerne Al 90
Estimate for IL 713 lb charge OF ntrogycerne 20 ~
Drilling into the rock Is included In the above. The
sea wall In the Gridron Is intended to be Of large
cut blocks regularly coursede The top Is TO be four
feet above highest water. The general height Is
twenythree feet at certain periods twenty eight feet
aud its thickness Is ten feet. Some OF tho rock
taken from the channel should be deposited behind
the wall TO the level of low water 10 form back.