The Portland daily press., 1896-02-19
THE PROPOSED LIGHT.

to support the awful strain which, any day
or night, may bear upon them. 1t is certain
that the work can be carried on only under
great danger and many Interruptions. The
officers feel that they can accomplish the
work, however, and have designed an in
genious plan.
The structure is to stand in about thirty
three feet of water, and will be supported on
disk piles sunk thirty feet In the sand The
floor of the watch house will be forty seven
feet above high water. Forged steel will be
used in the main structure, and the princi-
pal joints and connections will be of steel
castings. The essential parts below the
water line will be of massive dimensions
Bolts, pins, tie rods and other parts of small
sections have been avoided as tending to
weaken the structure. The masstveness of
the steel members will be continued above
the portion likely to be reached by the heavy
seas during violent storms. The problem
has been to make the structure as nearly
rigid to the enormous strains possible and
this is to be effected by joining ends of
members to steel-cast hubs by the use of
great steel rings shrunk on in a manner
somewhat like that followed in constructing
a built-up gun.
The structure Will be of the skeleton style,
and therefore will desxeithe sea full play
The section which will be most affected by
the force of the waves is that extending
from thirteen feet below the water line to
seventeen feet above, and in this section a
system of framing will be used which will
be at once strong, simple and rigid The ar
rangements is such that proximity of any
two members of bunching'' in the vicinity
oft he oforl linz So
has a clean sweep though the framing with
a minimum of resistance
The small resistance to the water afforded
by the individual members is distributed
evenly so as to reduce the likelihood that
shocks or vibrations will be communicated
to the upper portions Above this section Is
system of inclined beams and a central
column going up to the floor of the house.
The house for the lonely keepers and the
stores and the room for fog signal apparat-
us are to be of iron or ste ell and will be fire.
proof. boat will swing from an arm, so
that the keepers may abandon the place if
three is likelihood of the structure being de-
molished.
The method of construction is equally in
teresting. The submerged portion and the
heavier sections above water are to be as
semblcd in harbor and hoated to Diamond
Shoal by steel caisson secured to the out
side of the lower series, and calculated to
give a draught of about thirty feet when at
sea. When grounded in place the structure
is to be levelled up if necessary by water
jets, acting under the disks, water to be con-
yeyed through the pipes attached for sink
ing the piles. When everything is level the
piles are to be pumped down and secured in
place.
The constructive of a lighthouse on Dia-
mond Shoal, seven miles out at sea from
Cape Hatteras, has been the subject of seri-
| GUS consideration by the leading engineer
! experts of the army and navy for several
years, and, after experiments with skeleton
structures on the shoal and investigation as
to the strain a structure would be subjected
to by the fearful waves and winds that pre-
vail there almost continuously, there is still
q wide difference of opinion regarding the
feasibility of the scheme. The army engi-
neers have no doubt that an immense light
house can be located on the extreme outer
edge of the shoal, so built that it would be
iilvulnerable to the waves and shifting sands
that have brought about more engineering
problems to be overcome in constructing
a light than have been encountered pre-
viously by the government. 1t is argued by
several naval men, however, among them
Capt. Wilde, Naval Secretary of the Light
house Board, that even if light can be es-
tablished, which they very much question, it
is not necessary that the government should
go to the great expense of constructing it.
with the possibility that 1T might tumble
into the sea without warning, when light