The National tribune., 1905-12-21


teen years ago ne went out on the shore
to see one of his vessels aground and
one of her sailors frozen to death in the
rigging. Then he recorded a firm re-
solve to spend the rest of his life in en-
deavOring to protect the coast and pre-
vent such Sickening disasters.
The marine insurance companies, Ma
tional banks which do a marine bust
ness. the vessel owners and all of the
organizations representing vessel own
erS, officers and crews, have been i'm
pOrtuning the Government to erect
lighthouse off Cape Hatteras, and the
only obstacle has been the engineering
difficulties. In 1902 Acting Secretary
Spaulding of the Treasury reported
that the plans proposed would make the
cost of such a lighthouse S1,5S8,0O
There was little confidence at that time
in the safety of the structure proposed.
The plan which is now being carried out
and which was elaborated by Capt.
Eells, who has received contract for
the work, comprises for the foundation
a massive steel caisson in the form of
the lower portion of a cone, with cy-
Hndrical base. Upon this will be erected
the lighthouse proper, plate steel CYL
inder with a slight batter from base to
top, supporting a light of the first order
at $50 feet above tide level.
The caisson will be los feet in diam
eter at the bottom, so feet high and so
feet in diameter at the top. 1t will have
a double shell of steel plates, parallel
to each other and about six feet apart,
attached to "a upright inclined plate
Orders, which will divide the space be-
tween the shells into "a watertight COM
partments. 1t will have a double bot
tom about seven feet above the outer
i bottom edge of the caisSOn. This space
between the two floors is divided into
q -
tending from near the bottom of the "A
outer inclined girders horizontally on
the radial lines, within eight feet of the
center of the caisson. The central part
of the caisson will be in the form of an
open vertical shaft, Is feet in diameter,
extending from top to bottom, inclosed
by steel plates riveted together and at
tached or riveted to the steel Orders
extending horizontally from this shaft
to the inner edge of the "a inclined Cir
derS above described. These horizontal
girders, being about Is feet one above
the other, act as temporary floor beams
that will divide the caisson into five
large circular rooms
The construction is simple. Twenty
four upright inclined plate Orders ex-
tend from the top to the bottom of the
caisson on the radiaI lines. These Cir
ders are identically the same in shape,
size and weight, and form the principal
framework of the caisson. Twenty-four
plate Orders, which form the floor of
the caisSon near the bottom Of the in
.clined Orders just described. extend
horizontally on the radial lines to within
eight feet of the center of the structure.
Rolled steel plates about one-haf inch
thick are then riveted together, which
form the outer shell, covering the in
clined Orders from top to bottom, and
also similar steel plates are riyeted to-
gether and connected to the inside edge
of the inclined Orders, forming the dou-
bic conical shell separated into "a air.
and water-tight sections or wells by the
inclined Orders. The horizontal floor
Orders at the bottom of the caisson are
covered above and below, thus forming
a double shell floor made of rolled steel
plates riveted together and to the floor
girders.
WeIShty Caiss0n.
The central tube in the caisson, which
extends from top to bottom. is also made
of curved rolled steel plates attached to
the ends of the horizontal floor girders
and to the bracing, all of which, when
riyeted together, form the caisson into
a self-contained vessel of circular shape,
built sufficiently strong to stand a sea
voyage and the wind and wave pressure
after its final settlement into the sands
of the shoal. All the inside horizontal
Orders are covered at the different ele-
vations TO make temporary floors and
rooms in the caisson, and it is proposed
to place in these rooms at the time of
towing the boiler, engines, pumps der
ricks, dredging apparatus, concrete mix
ing machinery, water sand and cement,
and the different materials necessary
for sinking and filling and supplies and
equipment for the workmen.
1t Is purposed to fill a portion of the
space between the two outer shells and
part OF the bottom with concrete before
leaving the shipyards, so that the CATS
SON will draw about 81 feet Of water
and when all is in readiness tugboats
will be attached to ii and will tow 1t
to the location on the shoals.
While being towed to its location in
case of storm it's draught may be in
creased by partial scuttling, leaving q
smaller area above the surface OF the
water exposed to the wind and waves
Even in case Of its going ashore Ii would
then ground in deep water, where II
could easily be fioated again after the
storm by forcing the water out by ali
pressure or by pumping until 1t again
draws about Fl feet. 1t may then be
lowed TO It's location. and after reaching
It's destination will be held I'm place by
suitable anchors and cables It will be
scuttled by pumping water into the In
terror compartments, and 1t will be only
a matter Of a few hours before enough
water will have entered to sink 1t SO
rs to rest on the sand in about "a feet
OF water. leaving the top or deck at this
time about Sc feet above the surface OF
the ocean. The difference in tide at this
location is only about two feet, and the
shoal at the location selected for the
lighthouse on the four fathom contour
covers an area about two miles long and
one mile wide, and gradually deepens
on the seward side
The edges Of the caisson with the ad-
dit1onai weight from scuttling will set
lie INTO the sand a few feet immediately
until the bottom rests on the surface Of