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CARGO SECURING MANUAL
DUMB BARGE
“BARGE NAME”
Prepared by:
1
IMPORTANT
THESE GUIDANCE NOTES ONLY APPLY TO THE NAMED BARGE
OPERATING WITHIN THE FOLLOWING TRADING AREAS:SINGAPORE COASTAL WATERS INCLUDING VOYAGES TO BATAM
(FOR OTHER BARGES AND VOYAGES BEYOND THESE LIMITS FURTHER SECURING
MEASURES WILL HAVE TO BE AGREED WITH THE CLUB).
THE MASTER OF THE TUG TOWING A BARGE IS RESPONSIBLE FOR THE
BARGE AND THE CARGO THAT HE IS TOWING. HE MUST BE SATISFIED
THAT THE STEVEDORE HAS PROPERLY LOADED AND SECURED THE
CARGO BEFORE SAILING. IF HE IS NOT SATISFIED AND THE
STEVEDORE REFUSES TO CARRY OUT HIS REQUIREMENTS HE MUST
NOT SAIL. HE MUST ALSO BE SATISFIED THAT THE BARGE IS
SEAWORTHY AND THE TOWING BRIDLE AND OTHER EQUIPMENT IS IN
GOOD CONDITION.
MANY ACCIDENTS HAVE HAPPENING AROUND SINGAPORE BECAUSE BARGES HAVE BEEN
IN POOR CONDITION OR BADLY LOADED. CARGO HAS FALLEN OVER THE SIDE, TUGS
HAVE BEEN PULLED OVER BY THE BARGE AND CAPSIZED, KILLING CREWMEMBERS AND
BARGES HAVE SUNK WITH ALL CARGO ON BOARD.
The main causes of accidents are
1) LOADING CONTAINERS TOO HIGH.
When a strong wind squall hits the tug and barge, the barge is blown down-wind, the
tug has been pulled sideways and capsized. This especially happens when the tug is
not powerful enough. There is also a likelihood that the barge will suffer a loss of
stability.
2) LOADING FULL CONTAINERS ABOVE EMPTY OR LIGHT CONTAINERS
This makes the barge unstable. When the barge is pulled to one side or affected by
strong wind and seas during the north-east monsoon or squalls, the barge lists because
it is unstable and containers fall off. There is also a likelihood that the barge will
suffer a loss of stability.
3) NOT STOWING OR SECURING CARGO PROPERLY.
If cargo is not stowed properly it can fall over, slide or roll across the barge. When
the barge is caused to list by heavy seas, strong wind, the tug pulling to one side or
being pushed to one side by another vessel the cargo shifts, causing the barge to list.
Then more cargo shifts and there is a bigger list until cargo falls over the side or the
barge capsizes.
4) BARGE IS IN POOR CONDITION.
The steel inside the barge is wasted and there are holes between the tanks. Water
entering one tank runs into the next tank, the barge starts to list and the list gets bigger
as the water runs across to one side, causing the barge with cargo to capsize.
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5) COLLISION WITH OTHER VESSELS.
When crossing the Strait at night ships have collided with poorly lit barges. The
collision damages the barge allowing water into a compartment. The barge lists, cargo
shifts and either the barge capsizes or cargo is lost.
6) OVERLOADING
Overloaded barges have been lost due to taking on water after very small collisions.
When overloaded all certification and insurance cover is cancelled and the barge’s
stability can be seriously affected.
IT IS THE TUG MASTER’S DUTY TO TAKE PROPER PRECAUTIONS AND
ENSURE THAT NONE OF THE ABOVE HAPPEN.
CONTAINER LOADING & SECURING
On barges larger than length 200’ (61m), beam 50’ (15m) and draught 9’ (2.75m),
heavy containers (TEU 20’ containers of 18mt-20mt & FEU 40’ containers 25-30mt)
can be stowed 2 high and 3rd and 4th tiers of empty containers can be stowed on top.
Alternatively a bottom tier of full containers and 3 tiers of empty containers can be
carried or 4 tiers of empty containers can be carried.
IF MORE CONTAINERS ARE TO BE CARRIED THE BARGES STABILITY MUST BE
RECALCULATED AND THE STABILITY MANUAL CONSULTED. AT ALL TIMES THE
MINIMUM REQUIREMENTS OF THE STABILITY BOOK MUST BE COMPLIED WITH.
HEAVY CONTAINERS SHOULD ALWAYS BE STOWED ON THE BOTTOM TIER. THEY
MUST NEVER BE STOWED ON TOP OF LIGHTER CONTAINERS. LOADED CONTAINERS
SHOULD NEVER BE STOWED ON TOP OF EMPTY CONTAINERS.
Containers should be stowed fore and aft. The bottom tier should be stowed on flat
dunnage laid across the barge so that the corner posts are on the dunnage. Whenever
possible the containers should be stowed against the side-boards of the barge and each
container should be stowed closely against the next container. Any empty space left
between containers after the stow has been completed must be chocked with heavy pieces
of timber and wooden wedges.
THE OUTBOARD CONTAINERS MUST HAVE TWISTLOCK ON ALL TIERS AND
CONTAINERS ON THE 2nd, 3rd, OR 4th TIER WHICH ARE NOT STOWED AGAINST OTHER
CONTAINERS MUST HAVE POSITIONING CONES.
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GENERAL CARGO, STEEL COILS, CABLES & PIPES
STOWAGE & SECURING
Wherever possible cargo should be stowed against the side-boards of the barge or against
other cargo to prevent movement in case the barge lists or rolls. Lashing eyes should be
welded at suitable intervals (at least every 3 meters) onto the side-boards to make lashing
easy.
Cases and general cargo
should be secured so that
they cannot slide or fall over.
They should be chocked or
lashed at the bottom to
prevent sliding and stowed
against other cargo if possible
and chocked or lashed to
prevent
tipping
over.
Alternatively they can be
lashed against the side
boards.
Lashing to side board
Wooden wedge
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Steel coils should be stowed
‘on the roll’, fore & aft, with
heavy
wooden
wedges
hammered between the curve
of the coil and the deck of the
barge to prevent movement.
They should never be stowed
more than 1 high.
Bundles of pipes or wire
rods can be stowed across the
barge or fore and aft. Large
pipes should be stowed
across the barge, wooden
chocks or wedges hammered
between the curve of the pipe
and the deck of the barge and
cargo or chocking stowed
against the end of the pipes.
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LARGE, HEAVY CARGO
Special care must be taken when loading and securing large, heavy cargo. It is essential
to place large dunnage on the deck of the barge to spread the load. Tomming and wire
lashings should be used to ensure that, even if the barge lists, the cargo will not move. If
the Master is not familiar with securing heavy cargo it is recommended that he requests
the assistance of an experienced surveyor to attend.
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EXAMPLES OF CALCULATING THE BARGES STABILITY CONDITION
The following pages show various examples of calculating whether or not a barges
stability complies with the barges stability criteria.
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CALCULATING STABILITY
Example 1
1st and 2nd tiers heavy 20ft containers (20T), 3rd and 4th tiers empty 20ft containers
Assumption for calculation
•
Each tier fully stacked at 5 rows across by 8 containers fore and aft
•
Vertical Centre of Gravity, VCG, of containers is half height = half 2.59m =
1.295m
•
Weight of heavy container = 20T, weight of empty container = 2.4T
Taking moments about the deck to calculate the total cargo vertical centre of gravity,
CVCG, above the deck
Tier
Total Weight Tonnes
(W)
5 x 8 x 20 = 800
5 x 8 x 20 = 800
5 x 8 x 2.4 = 96
5 x 8 x 2.4 = 96
1792
1st
2nd
3rd
4th
CVCG
=
total moment
total weight
VCG
above deck (m)
1.295
3.885
6.475
9.065
=
5635.84
1792
Moment
(W x VCG)
1036
3108
621.6
870.24
5635.84
=
3.15m
From the Summary Table on page 7 we derive by interpolation that for a cargo weight
(deadweight) of 1792 we find that extreme draft is 2.48m and the maximum permissible
cargo VCG above deck is 4.24m
Extreme Draft (m)
2.500
2.476
2.250
Cargo VCG above deck (m)
4.058
4.242
5.950
Deadweight (T)
1815.78
1792
1570.03
The calculated CVCG of 3.15m is less than the maximum permissible CVCG of 4.24m
and therefore is within the permissible stability criteria and is safe.
With the extreme draft of 2.48m and the CVCG of 3.15m we can also determine using
the maximum cargo VCG curve on page 8 that the load plan is in the Safe Zone (see
Figure 1 on page 10).
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example 1
0.75
1
1.5
2
2.25
2.5
2.75
3
16.906
14.199
10.161
7.548
5.95
4.058
2
0.5
0.893
0.893
3.15
2.48
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CALCULATING STABILITY
Example 2
1st and 2nd tiers heavy 40ft containers (30T), 3rd and 4th tiers empty 40ft containers
Assumption for calculation
•
Each tier fully stacked at 5 rows across by 4 containers fore and aft
•
Vertical Centre of Gravity, VCG, of containers is half height = half 2.59m =
1.295m
•
Weight of heavy container = 30T, weight of empty container = 4.0T
Taking moments about the deck to calculate the total cargo vertical centre of gravity,
CVCG, above the deck
Tier
Total Weight Tonnes
(W)
5 x 4 x 30 = 600
5 x 4 x 30 = 600
5 x 4 x 4 = 80
5 x 4 x 4 = 80
1360
1st
2nd
3rd
4th
CVCG
=
total moment
total weight
VCG
above deck (m)
1.295
3.885
6.475
9.065
=
4351.2
1360
Moment
(W x VCG)
777
2331
518
725.2
4351.2
=
3.20m
From the Summary Table on page 7 we derive by interpolation that for a cargo weight
(deadweight) of 1360 we find that extreme draft is 2.03m and the maximum permissible
cargo VCG above deck is 7.34m
Extreme Draft (m)
2.250
2.033
2.000
Cargo VCG above deck (m)
5.950
7.337
7.548
Deadweight (T)
1570.03
1360
1328.06
The calculated CVCG of 3.20m is less than the maximum permissible CVCG of 7.34m
and therefore is within the permissible stability criteria and is safe.
With the extreme draft of 2.03m and the CVCG of 3.20m we can also determine using
the maximum cargo VCG curve on page 8 that the load plan is in the Safe Zone (see
Figure 2 on page 12).
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Example 2
3.20
2.03
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CALCULATING STABILITY
Example 3
1st and 2nd tiers 20ft containers of 15T in weight, 3rd tier 20ft containers of 8T in weight,
4th tier empty 20ft containers
Assumption for calculation
•
Each tier fully stacked at 5 rows across by 8 containers fore and aft
•
Vertical Centre of Gravity, VCG, of containers is half height = half 2.59m =
1.295m
•
Weight of empty 20ft containers is 2.4T
Taking moments about the deck to calculate the total cargo vertical centre of gravity,
CVCG, above the deck
Tier
Total Weight Tonnes
(W)
5 x 8 x 15 = 600
5 x 8 x 15 = 600
5 x 8 x 8 = 320
5 x 8 x 2.4 = 96
1616
1st
2nd
3rd
4th
CVCG
=
total moment
total weight
VCG
above deck (m)
1.295
3.885
6.475
9.065
=
6050.24
1616
Moment
(W x VCG)
777
2331
2072
870.24
6050.24
=
3.74m
From the Summary Table on page 7 we derive by interpolation that for a cargo weight
(deadweight) of 1616T we find that extreme draft is 2.30m and the maximum permissible
Cargo VCG above deck is 5.60m
Extreme Draft (m)
2.500
2.297
2.250
Cargo VCG above deck (m)
4.058
5.596
5.950
Deadweight (T)
1815.78
1616
1570.03
The calculated CVCG of 3.74m is less than the maximum permissible CVCG of 5.60m
and therefore is within the permissible stability criteria and is safe.
With the extreme draft of 2.30m and the CVCG of 3.74m we can also determine using
the maximum cargo VCG curve on page 8 that the load plan is in the Safe Zone (see
Figure 3 on page 14).
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Example 3
3.74m
2.30m
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CALCULATING STABILITY
Example 4
1st and 2nd tiers heavy 20ft containers (20T) and 3rd tier 20ft containers of 10T in weight
Assumption for calculation
•
Each tier fully stacked at 5 rows across by 8 containers fore and aft
•
Vertical Centre of Gravity, VCG, of containers is half height = half 2.59m =
1.295m
Taking moments about the deck to calculate the total cargo vertical centre of gravity,
CVCG, above the deck
Tier
Total Weight Tonnes
(W)
5 x 8 x 20 = 800
5 x 8 x 20 = 800
5 x 8 x 10 = 400
1st
2nd
3rd
VCG
above deck (m)
1.295
3.885
6.475
Moment
(W x VCG)
1036
3108
2590
2000
CVCG
=
total moment
total weight
6734
=
6734
2000
=
3.37m
From the Summary Table on page 7 we derive by interpolation that for a cargo weight
(deadweight) of 2000T we find that extreme draft is 2.68m and the maximum permissible
Cargo VCG above deck is 2.42m
Extreme Draft (m)
2.855
2.684
2.500
Cargo VCG above deck (m)
0.893
2.417
4.058
Deadweight (T)
2171.09
2000
1815.78
The calculated CVCG of 3.37m is greater than the maximum permissible CVCG of
2.42m and therefore is outside the permissible stability criteria and is NOT SAFE.
With the extreme draft of 2.68m and the CVCG of 3.37m we can also determine using
the maximum cargo VCG curve on page 8 that the load plan is in the UNSAFE ZONE
(see Figure 4 on page 16).
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example 4
3.37m
2.68m
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CALCULATING STABILITY
Example 5
Mixed Cargo - Container and General Cargo
Stowage:
Containers, tier 1 and 2 heavy (20T), tiers 3 and 4 empty (2.4T) x 4 bays, Frames 2 – 16
Boxes, General, Stowed to 3.8m high, total 325T, Frames 16 - 20
Steel Coils, 1.5m dia x 2.4 width x 12T, stowed fore and aft ‘on the roll’, 3 rows x 9 coils
per row, Frames 20 -24
Pipes, 40ft x 30ins dia x 7T, stowed across the barge, stacked 3 high, Frames 24 - 30
Assumption for calculation
•
•
•
•
Vertical Centre of Gravity, VCG, of containers is half height = half 2.59m =
1.295m
Vertical Centre of Gravity, VCG, of boxes is half height = half 3.8m = 1.9m
Vertical Centre of Gravity of coils is half diameter = half 1.5m = 0.75m
Vertical Centre of Gravity of pipe is half diameter = half 0.762m = 0.381m
Taking moments about the deck to calculate the total cargo vertical centre of gravity,
CVCG, above the deck
Cargo
Frames Tier
Containers 2 -16
1
2
3
4
Sub total
Wt (T)
5x4x20= 400
5x4x20= 400
5x4x2.4= 48
5x4x2.4= 48
896
VCG(m)
1.295
3.885
6.475
9.065
Moment
518
1554
310.8
435.12
2817.92
Boxes
16 – 20
1
325
1.9
617.5
Coils
20 – 24
1
3x9x12 = 324
0.75
243
Pipes
24 – 32
1
2
3
0.381
1.143
1.905
Sub total
14x7=98
13x7=91
12x7=84
273
37.34
104.01
160.02
301.37
Totals
1818
18
3979.79
CVCG
=
total moment
=
3979.79
=
2.19m
total weight
1818
From the Summary Table on page 7 we derive by interpolation that for a cargo weight
(deadweight) of 1818T we find that extreme draft is 2.50m and the maximum permissible
Cargo VCG above deck is 4.04m
Extreme Draft (m)
2.855
2.504
2.500
Cargo VCG above deck (m)
0.893
4.038
4.058
Deadweight (T)
2171.09
1818
1815.78
The calculated CVCG of 2.19m is less than the maximum permissible CVCG of 4.04m
and therefore is within the permissible stability criteria and is safe.
With the extreme draft of 2.50m and the CVCG of 2.19m we can also determine using
the maximum cargo VCG curve on page 8 that the load plan is in the Safe Zone (see
Figure 5 on page 19).
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Example 5
20