2. Question :(a)
Determining the optimum track by using the
following :
1.Monthly Routeing Chart
2.Wave Chart
3.Ice Chart
4.Information on Current
5.Prevailing Wind
6.Ice
7.Other sources of weather information such as
Navtex.
3. 1. MONTHLY ROUTEING CHART
Routeing Charts published for the North and
South Atlantic, Indian, and North and South
Pacific Oceans. Each chart has twelve versions,
one for each month and assist the navigator to
plan an ocean passage for any time of year . The
following data is available on a Monthly
Routeing Chart :
1. An outline of the surrounding land areas.
2.The position of major ports.
3.The recognized shipping routes between major
ports, with distances.
4.Data on wind speed, direction and forces.
4. 1.MONTHLY ROUTEING CHART
5. Incidence of low visibility and Frequency of
storms.
6.Data on sea and air temperature, air pressure
and ice limit.
7.Data on ocean currents.
8.The limits of Load line zones.
9.The locations of ocean weather ships.
5.
6.
7. C u r r e n t R o s e
Determining Current
The Current Rose which is Represented on Routeing
Chart.
High Consistency
Moderate Consistency
Low Consistency
Probable direction when
observation count is low
10. Routeing Charts:
North Atlantic Ocean
BA5124(1) North Atlantic Ocean Routeing Chart--January
BA5124(2) North Atlantic Ocean Routeing Chart--February
BA5124(3) North Atlantic Ocean Routeing Chart—March
BA5124(4) North Atlantic Ocean Routeing Chart--April
BA5124(5) North Atlantic Ocean Routeing Chart--May
BA5124(6) North Atlantic Ocean Routeing Chart--June
BA5124(7) North Atlantic Ocean Routeing Chart--July
BA5124(8) North Atlantic Ocean Routeing Chart--August
11. 2. WAVE CHART
A. Wave analysis chart- These charts show
isopleths(line joining all places having the same
value) of wave heights, in meters, and their
direction , based on actual report.
B. Wave prognosis chart-These charts show
isopleths of wave heights in meter, predicted for a
specified future time. They are made by
professional meteorologist and based on a study
of weather analysis chart, weather prognosis
charts, wave analysis charts etc.
12.
13.
14. A heavy lift cargo ship for instance will use the
wave chart during the planning of the passage
to avoid areas where the wave height will be
above the allowed limit for the vessel safe
passage. With the use of the wave chart the
vessel can be safely navigated from one part of
the ocean to the other.
15. 3. ICE CHART
Ice analysis chart-These chart indicated amounts and
boundaries of each type of ice , icepacks, ice leads and
icebergs based on actual observation
Ice prognosis chart-This charts contain the same type
of information as ice analysis charts. But predicted for
a specified future time and are usually made 12 hours
and 24 hours in advance.
After studying the situation shown by the ice analysis
charts and taking into account various factors such as
winds, currents, temperature of air and sea etc. the
prognosis charts are made by expert.
21. 4. INFORMATION ON CURRENT
Ocean currents are the circulations of water caused by
various factors. Ocean currents have two different
methods of moving water. Surface currents move as a
result of blowing winds and are influenced by
atmospheric factors. Deep ocean currents move as a
result of the density differences that are present in the
ocean.
The two largest currents on earth are the Kuroshio
Current which circulates near Japan, and the Antarctic
Circumpolar Current, which circulates around
Antarctica.
22. Currents plan an important role in navigation as well.
In addition to being able to avoid trash and icebergs,
knowledge of currents is essential to the reduction of
shipping costs and fuel consumption. Today, shipping
companies and even sailing races often use currents to
reduce time spent at sea.
It is important to understand that ocean circulation
is very dynamic, and this following map only shows
the average position of these currents.
Additionally, this map does not show subsurface and
deep ocean circulation, both of which are very
important in ocean dynamics.
26. Oya Siwo:
cold
current
soutward
past Asia
Kuro Siwo
warm
current to
north
East
Australian
warm
current to
south
West Wind Drift circles Antarctcia
Cold Peruvian
current brings
fish toward
shore
California
current
brings cold
water south
North Pacific
Drift brings
warm water
eastward
Some flow into arctic ocean
27. Publication for Ocean Current data
Ocean current data can be found in a number of
publication such as :-
Routeing chart.
Admiralty sailing direction.
Ocean passage for the world.
32. C u r r e n t R o s e
Determining Current
The Current Rose which is Represented on Routeing
Chart.
High Consistency
Moderate Consistency
Low Consistency
Probable direction when observation
count is low
33. 5. PREVAILING WIND
A wind that blows predominantly from a single general
direction. For example the trade winds of the tropics,
which blow from the east throughout the year, are
prevailing winds.
The earth is encircled by several broad prevailing wind
belts, which are separated by narrower regions of either
subsidence or ascent. The direction and location of these
wind belts are determined by solar radiation and the
rotation of the earth. The three primary circulation cells are
known as the: Hadley cell; Ferrell cell; and Polar cell.
The oceans of the world are covered by a set of ships board
chart shows the coastline, the approximate strengths and
direction of prevailing wind.
By using routeing chart we can find the information about
prevailing wind.
34.
35. 6. ICE
Ice is a solid form of water, or, more generally, any frozen volatile.
Sea ice occurs in both the Arctic and Antarctic.
In the Northern Hemisphere, it can currently exist as
far south as Bohai Bay, China (approximately 38
degrees north latitude), which is actually about 700
kilometers (435 miles) closer to the Equator than it is
to the North Pole.
In the Southern Hemisphere, sea ice only develops
around Antarctica, occurring as far north as 55
degrees south latitude.
Sea ice grows during the winter months and melts
during the summer months, but some sea ice remains
all year in certain regions. About 15 percent of the
world's oceans are covered by sea ice during part of
the year.
36. 7.OTHER SOURCE OF WEATHER INFORMATION SUCH AS NAVTEX
Navtex is a navigational telex service developed by IMO,
and broadcasted by means of narrow band direct printing
techniques on the frequency 518 kHz, for the promulgation
of navigational, meteorological warnings and urgent
information to ships. It is incorporated in the GMDSS and
is achieved by transmitters allocated to cover a specific
Navtex area..
The other components of the total GMDSS are:
Radio telephony broadcasts, VHF out to 30 miles, MF to
150 miles, HF worldwide,
The International Maritime Satellite (INMARSAT) Safety
NET over the oceans, roughly 65°N to 65°S.,
HF radio-facsimile and radio-teletype.