Crawford avalanche. (Grayling, Mich.) 1879-19??, 1895-12-26
DARING ENGINEERING.
a Great Lighthouse In the Opsn
Ocean.

difficult and costly piece Of engin-
eering has been undertaken by the
United States Government in the pro-
1ected establishment of "A great light
house in the open ocean off Diamond
Shoal, seven miles from the present
Hatteras Light and bearing almost
due east. This is one of the most dar-
ing schemes that army officers have
dealt with since General Casey, chief
of engineers, successfully undermined
the great Washington monument and
placed there solid foundation ex-
pected to support that structure for
ages to come. Surrounding this new
plan, however. there is foreboding Of
failure. and IL is predicted thus early
that 100000 is to be sunk literally
as well as metaphOrically in the sea.
If such Il structure is placed there
and stands without serious damage
the onslaught of the seas for five years,
according to Il leading army engineer,
this Government will have accomplish
ed it's greatest triumph i'm this branch
of science
The height Of the focal plane above
water in the prospectus is given as
100 feet, and the structure is to stand
in thirty-three feet of water, and to be
supported on disk piles sunk to
depth Of thirty feet in the sand. The
diameter from centre to centre of
vertical members Of the foundation
series is to be sixty feet and the height
of the floor of the house above water
forty-seven feet The main portion
of the structure is to be constructed of
forged steel members, with principal
joints and connections formed OF
steel castings.
A special feature Of the design Is to
make all essential parts below the
water line of massive dimensions, as
well as all those parts above the
water line which will be subject to the
action of wind and waves. The use Of
bolts, keys, screws and other small
sections or dimensions which would be
rapidly weakened by corrOsiOn, will be
avoided az far as possible. Joints
and connections are to he made alb
solutely rigid to all possible strains
and to be as strong as the members
| themselves. This Is to be effected by
| Joining ends of members to steel cast
hubs by the use of massive steel rings
shrunk on in a manner apprOximating
that followed in "builtup" gun con-
! structiOn.
In the foundation series, besides the
massive members necessary for the
strength OF the tower when in place,
there will be certain other tie rods
of lighter section, which are added for
greater security to stiffen the frame
work while 1t is fioated and while be-
ing placed and grounded on the shoal.
It is proposed by the board to con-
struct the screw pile structure in the
harbor and float ii out by steel cylin-
drical caissons calculated to give n
draught Of thirty feet when at sea. This
part of the light Is then to be sunk
probably fifty feet down in the bottom
nv hydraulics until firm hold Is Sc
cured. 1t is then proposed to build up
from the skeleton arrangement until
the lightkeeper's apartments have been
completed, and the height secured Tor
the great lens which is to throw It's
light twenty-five miles in all direc-
| tons.
The work is to begin this winter, and
II is proposed to complete the hght
in two OF three years.