Design and Analysis of Lighthouse chapter 1
CHAPTER 1
INTRODUCTION
1.1 INTRODUCTION
A lighthouse is a
tower, building, or other type of structure designed to emit light from a
system of lamps and lenses and used as a navigational aid for mariners and
local fisherman at sea or on inland waterways. Lighthouses mark dangerous
coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial
navigation. Once widely used, the number of operational lighthouses has
declined due to the expense of maintenance and replacement by modern electronic
navigational systems. A lighthouse light is a
concentrated beam, focused by special lenses. Because of its highly increased
intensity, this beam of light can travel a very long distance.
1.2
SPECIFICATION
Ø Plinth
area of Ground floor is 1225 Sq.ft.
Ø Plinth
area of first floor to sixth floor is 324 sq.ft of each.
Ø Windows
with glass panel of 1.2m X 1.2m.
Ø Door
of Wood paneled with single flush is of 1.2m X 2.1m
Ø Steps
of Dog legged with Tread is 230mm and Rise is 150mm.
Ø Total
No. of steps in the Lighthouse is 108 steps.
Ø Hydraulic
room less Lift is provided with the maximum capacity of 10 passengers.
Ø Shear
wall is provided in the structure.
Ø Structural
Elements are:
·
Beam
·
Column
·
Slab
·
Staircase
·
Pile
Foundation
·
Pile cap
Ø No.
of pile is 56
Ø Plan
Specification
·
Office room
·
Waiting
room
·
Keeper’s
room
·
Generator
and power supply room
·
Lift car
Ø Lantern
room specification
·
Fresnel
lens of Second order is up to 20 nautical miles.
·
Fixed lamp
is Xenon Lamp of 1000 watt bulb.
Ø Height
of Tower
·
Height is
24m (80ft).
·
Focal plane
Height is 20.5m (67ft).
Height of
Light in meter
|
Height of
Eye in meter
|
Distance
of light in Nautical miles
|
Distance
in Kilometer
|
20.5
|
3
|
13
|
24
|
5
|
14
|
26
|
|
10
|
16
|
30
|
Table
1.1 Distance Travel of Light
Ø Proposed
Land Area is Karaikal
·
For the Use
of Navigation of Sea Sailors.
·
For the Use
of Navigation of Karaikal Port.
·
For the Use
of Navigation of River Arasalar river.
·
For the Use
of Navigation Fishermen’s.
1.3 LIGHTHOUSE
TERMS
1.3.1
Lightning Rod
Lighthouses are struck by lightning a regular basis.
Metal poles called lightning rods are attached to the tops of lighthouses to
help minimize the damage created by lightning strikes. A lightning rod is
attached to a thick copper wire that runs from the top of the lighthouses down
to the ground. When lightning strikes the tower, it enters through the
lightning rod, travels down the wire, and goes into the ground where it can
cause less damage.
1.3.2
Cupola
The cupola is the roof
of the lantern room. Because temperatures inside the lantern room can often
soar well above 110 degrees, a metal ball at the top of the cupola provides
ventilation and allows the heat to escape.
1.3.3 Lantern Room
The lantern room is the most important room in
a lighthouse because that is where the lighthouse beacon (or light) is located.
The walls of the lantern room are made of glass so the light can be seen at
night.
1.3.4 Widow’s Walk
Named after the wives of sailors who watch
for the return of their husband’s ship from the top of their house, the widow’s
walk is a narrow platform that provides access to the outside of the lantern
room.
1.3.5 Gallery Deck
The gallery deck is a platform that circles
the tower just below the lantern room. You can access the gallery deck from the
service room through a heavy iron door. Lighthouse keepers would watch the
weather and scan the horizon for approaching ships from the gallery deck.
1.3.6 Service Room
The service room is the Keepers room where
keepers would store cleaning equipment, spare parts for the beacon, and tools
for working on the lighthouse.
1.3.7 Watch Room
The watch room is the
office room where keepers kept their log. A log is a kind of journal that keepers
wrote brief descriptions of daily events, weather conditions, and notes in.
Additional items used by keepers while on watch or while working at the top of
the lighthouse were stored in this room as well.
1.3.8 Windows
Most lighthouses had
windows to cool the tower and provide light.
1.3.9
Staircase
Most lighthouses have a long staircase leading
from the bottom of the tower to the top.
1.3.10
Counterweight Well
Before electricity, lighthouse beacons were
turned using a system of gears powered by weights that hung down the center of
the tower. The counterweight well would catch any weights that broke loose.
1.3.11
Entrance
Every lighthouse has a door leading into it.
1.3.12
Foundation
A lighthouse’s
foundation keeps it from falling over.
1.3.13
LIGHTS - DISTANCE OFF
WHEN RISING OR DIPPING (NAUTICAL MILES)
Lights - distance off when rising or dipping
(Nautical Miles)
|
||||||||||
Height of
Eye Meters
|
||||||||||
Height of Light
Meters |
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
10
|
8.7
|
9.5
|
10.2
|
10.8
|
11.3
|
11.7
|
12.1
|
12.5
|
12.8
|
13.2
|
12
|
9.3
|
10.1
|
10.8
|
11.4
|
11.9
|
12.3
|
12.7
|
13.1
|
13.4
|
13.8
|
14
|
9.9
|
10.7
|
11.4
|
12.0
|
12.5
|
12.9
|
13.3
|
13.7
|
14.0
|
14.4
|
16
|
10.4
|
11.2
|
11.9
|
12.5
|
13.0
|
13.4
|
13.8
|
14.2
|
14.5
|
14.9
|
18
|
10.9
|
11.7
|
12.4
|
13.0
|
13.5
|
13.9
|
14.3
|
14.7
|
15.0
|
15.4
|
20
|
11.4
|
12.2
|
12.9
|
13.5
|
14.0
|
14.4
|
14.8
|
15.2
|
15.5
|
15.9
|
22
|
11.9
|
12.7
|
13.4
|
14.0
|
14.5
|
14.9
|
15.3
|
15.7
|
16.0
|
16.4
|
24
|
12.3
|
13.1
|
13.8
|
14.4
|
14.9
|
15.3
|
15.7
|
16.1
|
16.4
|
17.0
|
26
|
12.7
|
13.5
|
14.2
|
14.8
|
15.3
|
15.7
|
16.1
|
16.5
|
16.8
|
17.2
|
28
|
13.1
|
13.9
|
14.6
|
15.2
|
15.7
|
16.1
|
16.5
|
16.9
|
17.2
|
17.6
|
30
|
13.5
|
14.3
|
15.0
|
15.6
|
16.1
|
16.5
|
16.9
|
17.2
|
17.6
|
18.0
|
32
|
13.9
|
14.7
|
15.4
|
16.0
|
16.5
|
16.9
|
17.3
|
17.7
|
18.0
|
18.4
|
34
|
14.2
|
15.0
|
15.7
|
16.3
|
16.8
|
17.2
|
17.6
|
18.0
|
18.3
|
18.7
|
36
|
14.6
|
15.4
|
16.1
|
16.7
|
17.2
|
17.6
|
18.0
|
18.4
|
18.7
|
19.1
|
38
|
14.9
|
15.7
|
16.4
|
17.0
|
17.5
|
17.9
|
18.3
|
18.7
|
19.0
|
19.4
|
40
|
15.3
|
16.1
|
16.8
|
17.4
|
17.9
|
18.2
|
18.7
|
19.1
|
19.4
|
19.8
|
42
|
15.6
|
16.4
|
17.1
|
17.7
|
18.2
|
18.6
|
19.0
|
19.4
|
19.7
|
20.1
|
44
|
15.9
|
16.7
|
17.4
|
18.0
|
19.5
|
18.9
|
19.3
|
19.7
|
20.0
|
20.4
|
46
|
16.2
|
17.0
|
17.7
|
18.3
|
18.8
|
19.2
|
19.6
|
20.0
|
20.3
|
20.7
|
48
|
16.5
|
17.3
|
18.0
|
18.6
|
19.1
|
19.5
|
19.9
|
20.3
|
20.6
|
21.0
|
50
|
16.8
|
17.6
|
18.3
|
18.9
|
19.4
|
19.8
|
20.2
|
20.6
|
20.9
|
21.3
|
55
|
17.5
|
18.3
|
19.0
|
19.6
|
20.1
|
20.5
|
20.9
|
21.3
|
21.6
|
22.0
|
60
|
18.2
|
19.0
|
19.7
|
20.3
|
20.8
|
21.2
|
21.6
|
22.0
|
22.3
|
22.7
|
65
|
18.9
|
19.7
|
20.4
|
21.0
|
21.5
|
21.9
|
22.3
|
22.7
|
23.0
|
23.4
|
70
|
19.5
|
20.3
|
21.0
|
21.6
|
22.1
|
22.5
|
22.9
|
23.2
|
23.6
|
24.0
|
75
|
20.1
|
20.9
|
21.6
|
22.2
|
22.7
|
23.1
|
23.5
|
23.9
|
24.2
|
24.6
|
80
|
20.7
|
21.5
|
22.2
|
22.8
|
23.3
|
23.7
|
24.1
|
24.5
|
24.8
|
25.2
|
85
|
21.3
|
22.1
|
22.8
|
23.4
|
23.9
|
24.3
|
24.7
|
15.1
|
25.4
|
25.8
|
90
|
21.8
|
22.6
|
23.3
|
23.9
|
24.4
|
24.8
|
25.2
|
15.6
|
25.9
|
26.3
|
95
|
22.4
|
23.2
|
23.9
|
24.5
|
25.0
|
25.4
|
25.8
|
16.2
|
26.5
|
26.9
|
Table
1.2 Lights - Distance Off When Rising
or Dipping (Nautical Miles)
1.3.14
Basic Operation of the Lens
The operation of the
lens itself is quite simple by today’s standards, but was considered
revolutionary when it was first developed.
1.3.15
Illuminants
Early illuminants such as wood and coal were used to
produce light in lighthouses. Forty years before the Fresnel lens was
invented, Swiss Physicist Ami Argand had invented the "hollow" wick
for use in his lamp. The hollow wick was an important discovery over
usage of the solid wick for many reasons. It burned brighter as well as
cleaner. This would be particularly important later on when the Fresnel
lens came along. With its hundreds of prisms to maintain it would have
been a constant task just keeping them clean. Even with the hollow wick,
daily cleaning was still necessary but the buildup of soot and smoke wasn't
nearly as bad. As cleaner, safer, and more efficient illuminants were
discovered, the more traditional methods were no longer used. Below is a
list of primary illuminants used for light and an approximate time frame in
which they were used.
Whale Oil.......1720-1864
Lard Oil..........1864-1884
Kerosene.......1884-1955
Acetylene......1904-1980
Electricity......1898- present
1.3.16
Photographs of Lenses
In 1939, President
Roosevelt signed legislation which transferred jurisdiction of the nation's
lighthouses to the Coast Guard. As technological advances such as fog
detectors, sun relays, and electricity became widely accepted, more and more
stations were automated, eliminating the need for lighthouse keepers.
Aero beacons, plastic lenses and other modern optics were also being
developed. These modern optics were smaller, more cost effective to use
and maintain, and began replacing the Fresnel lens in the lantern rooms across
the nation. While most Fresnel lenses have been removed from the
lighthouses, thankfully, a number of the classical Fresnel lenses have been
saved and are on display in lighthouse and maritime museums across the
country.
1.3.17 Order by size
Order
|
Height
|
Inside
Diameter |
First
|
7' 10"
|
6' 1"
|
Second
|
6' 1"
|
4' 7"
|
Third
|
4' 8"
|
3' 3"
|
Third and 1/2
|
3' 0"
|
2' 5 1/2"
|
Fourth
|
2' 4"
|
1' 8"
|
Fifth
|
1' 8"
|
1' 3"
|
Sixth
|
1' 5"
|
1' 0"
|
Table 1.3 Order of Size
1.3.18 Source
Guardians of the Golden Gate:
Lighthouses and Lifeboat Stations of San Francisco Bay Ralph
Shanks and Lisa Woo Shanks, editor. 1995, Costano Books, ISBN: 0-930268-083.
1.3.19 Application
The
Second Order lens was used in seacoast and warning lights to mark headlands,
dangerous oceanic shoals, rocks or reefs. It was used quite frequently in the
Great Lakes Lights, on islands, and in marking sounds. Two of the Great Lakes
lights that were outfitted with this order of lens were White Shoal &
Grosse Point.
1.3.20 Specifications
Lens height:
|
81.46"
|
Focal length:
|
27.6"
|
Weight of assembly:
|
3,530 lbs.
|
Relative brightness (over sixth
order):
|
11.54x
|
Useful range:
|
Up to 20 nautical miles
|
Number in US Lighthouses in
1884:
|
19
|
Number in US Lighthouses in
1922:
|
26
|
Oil consumption per hour
|
17.5 oz.
|
1.3.21 References
Annual Report
of the Lighthouse Board, 1884
The United States Lighthouse Service, Dept. of Commerce, 1915
Aids to Navigation Manual, US Coast Guard, 1945
Comparative Table of Lens Orders, Mabel A. Baiges, 1988
Letter from Al & Helen Gademsky, 07/02/01
The United States Lighthouse Service, Dept. of Commerce, 1915
Aids to Navigation Manual, US Coast Guard, 1945
Comparative Table of Lens Orders, Mabel A. Baiges, 1988
Letter from Al & Helen Gademsky, 07/02/01
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