Effect of the Minimum Ballast Condition on Bulk Carrier ... · Effect of the Minimum Ballast Condition on Bulk Carrier Manoeuvrability for INTERCARGO. A part of BMT in Maritime Transport

Effect of the Minimum Ballast Condition on Bulk Carrier Manoeuvrability

for INTERCARGO.

A part of BMT in Maritime Transport

ISSUE DATE: 19th September 2008

REPORT NO: C12145.1R

INTERCARGO Bulk Carrier Manoeuvrability

1 Report No: C12145.1R

CONTENTS 1 TERMS OF REFERENCE............................................................................................. 2

2 BACKGROUND............................................................................................................ 2

3 OBJECTIVES OF THE STUDY..................................................................................... 2

4 METHODOLOGY.......................................................................................................... 2

4.1 General.................................................................................................................. 2

4.2 Capesize Bulk Carrier............................................................................................ 3

4.3 Met-ocean Conditions for Tubarao and Ponto de Madeira..................................... 3

4.4 Matrix of Scenarios................................................................................................ 4

5 SIMULATION RESULTS .............................................................................................. 6

6 DISCUSSION................................................................................................................ 8

7 CONCLUSIONS.......................................................................................................... 10

8 REFERENCES............................................................................................................ 11

APPENDIX A – SIMULATION RESULTS........................................................................... 12

Document History

Version Changes By

1 Draft for Release DA, SB

2 Comments from client added SB

Information contained in this document is commercial-in-confidence and should not be transmitted to a

third party without prior written agreement of BMT SeaTech Ltd. © Copyright BMT SeaTech Ltd 2008

Document Information

Project Bulk Carrier Manoeuvrability

Report Title Effect of the Minimum Ballast Condition on Bulk Carrier Manoeuvrability

Client INTERCARGO

Report ref: C12145.1R

Prepared by: Mr Dimitrios Argyros Naval Architect, BMT SeaTech Ltd

Approved by: Mr Simon Burnay Group Manager – Marine Safety & Compliance, BMT SeaTech Ltd



1 TERMS OF REFERENCE

BMT SeaTech Ltd (BMT) was instructed by INTERCARGO to conduct a simulation study to

assess the effect on ship manoeuvrability of minimum ballast conditions for Capesize bulk

carriers.

The study was undertaken by BMT staff with the simulations being conducted using the PC

Rembrandt ship handling and manoeuvring simulator, developed by BMT. This report

describes the methodology adopted for this project and includes the relevant analysis, a

summary of results, and appropriate conclusions.

2 BACKGROUND

Due to the increased demand for raw materials such as iron ore, it is understood that

a number of bulk terminals have been taking measures to optimise port throughput. This has

resulted in terminals requesting fast ship turn-around times necessitating a very light ballast

arrival condition in order to be able to load at high rates e.g. at up to 16000 tonnes per hour;

in some cases also allowing 90% propeller immersion to facilitate this.

It is therefore understood that a number of operators of large bulk carriers (Capesize) have

reported problems with vessel manoeuvrability due to the requirement for arriving in a

loading condition that results in a very large trim by the stern and significantly higher

windage. Both of these effects are well known to have detrimental effects on vessel

manoeuvrability ref [1], relative to normal loading conditions.

3 OBJECTIVES OF THE STUDY

The aim of this study is to present and quantify the differences in vessel manoeuvrability due

to the requirement for a minimum ballast condition versus the normal arrival loading

condition.

4 METHODOLOGY

4.1 General

The methodology employed for this study was to run a set of simulations for two ports where

the loading rates are known to be 16,000 tonnes per hour ref [2] and [3]. Simulations were

completed for arrival scenarios at the ports of Tubarao and Ponto de Madeira in Brazil,

based on a matrix of scenarios derived from an analysis of met-ocean conditions for the

area. Figures 4.1(a) – (b) present the nautical charts for Tubarao and Ponto De Madeira

respectively, courtesy of UKHO.



Figure 4.1(a) – Tubarao Bulk Terminal Figure 4.1(b) – Ponto de Madeira Bulk Terminal

4.2 Capesize Bulk Carrier

For the purpose of simulating the vessels which call at these ports, a Capesize vessel was

selected that was felt to be typical for this class of ship. A ship model was provided with the

principal characteristics given in Table 4.1 below.

Parameter Normal Loaded

Condition

Normal Ballast

Condition

Minimum Ballast

Condition

Length Overall [m] 289.0 289.0 289.0

Length Between Perp. [m] 279.0 279.0 279.0

Breadth [m] 45.0 45.0 45.0

Mean Draught [m] 18.0 8.2 5.3

Stern Trim [m] 0.0 1.2 5.15

Propeller Immersion [%] 100% 100% 95%

Rudder Immersion [% of area] 100% 73% 65%

Table 4.1 – 180,000 DWT Capesize Vessel Model Principal Particulars

4.3 Met-ocean Conditions for Tubarao and Ponto de Madeira

A brief analysis of wind, wave and current conditions was undertaken for the ports to be

assessed. The results of this analysis are as follows:

Figures 4.2(a) – (c) present the data used for the Port of Tubarao to establish the tide

heights, wind and wave data to be used in the simulations. Figures 4.3(a) – (c) present the

equivalent data for Ponto de Madeira.



Tubarao Ponto de Madeira

Figure 4.2(a) – Tubarao Tidal Data Figure 4.3(a) – Ponto de Madeira Tidal Data

Figure 4.2(b) – Tubarao Wind Data Figure 4.3(b) – Ponto de Madeira Wind Data

Figure 4.2(c) – Tubarao Wave Data Figure 4.3(c) – Ponto de Madeira Wave Data

4.4 Matrix of Scenarios

Based on the analysis of the data presented in Section 4.3, the scenario matrix was derived

and is presented in Table 4.2 below. The scenario matrix was derived by analysing the data

presented in Figures 4.2 and 4.3 to obtain the following information:

- Typical tidal ranges in neap and spring cycles.

- Wind and wave data relating to the probability of occurrence e.g. conditions that

occur 50% 25%, 10% and 1% of the time.

- Current conditions based on available public data e.g. Admiralty South American

Pilot.



Tidal heights were selected for each port that gave a typical height of tide combined with the

relevant current flow. For Tubarao, it was determined that there is a general South-west

current flow parallel to the shoreline of circa 1 knot. This was therefore applied with a tidal

height of 0.8m representing a typical mid-tide condition (i.e. maximum current flow). The

current was defined to be realistic inside the port breakwaters such that the effect is reduced

when close to the berths.

For Ponto de Madeira, the tidal height is much larger (reaching a range of up to 6 metres), in

which case stronger currents can be expected. Based on the data available, a 2 knot

current was selected as being significant, but not extreme. Again a mid-range tidal height of

4 metres was selected.

For wind and wave conditions, analysis was made of the percentage occurrence data in

Figures 4.2 and 4.3 to derive the typical wind speeds and directions for prevailing conditions

(i.e. the majority of the time, or circa 30-50% probability), stronger conditions ( e.g. 25% or

10% probability) and storm conditions (less than 5% probability). The vales used as

presented in Table 4.2 were only included if they represented feasible conditions, i.e. they

are practically as well as theoretically possible to occur and hence conditions with a very low

probabilities of occurrence were not included.

Wind Current Waves

Port ID Condition Speed [kts]

Dir [deg]

Speed [kts]

Dir [deg]

Tide Height +CD [m]

Ht [m]

Period [sec]

Dir [deg]

T1 Ballast 10 30 1 225 0.8 1.5 7.5 90

T2 Ballast 14 30 1 225 0.8 1.5 7.5 90

T3 Ballast 20 30 1 225 0.8 2.5 10.5 90

T4 Light Ballast 10 30 1 225 0.8 1.5 7.5 90

T5 Light Ballast 14 30 1 225 0.8 1.5 7.5 90

Tubarao

T6 Light Ballast 20 30 1 225 0.8 2.5 10.5 90

M1 Ballast 15 90 2 0 4 1.5 5.5 30

M2 Ballast 20 90 2 0 4 2.5 6.5 30

M3 Ballast 20 30 2 0 4 2.5 7.5 30

M4 Light Ballast 15 90 2 0 4 1.5 5.5 30

M5 Light Ballast 20 90 2 0 4 2.5 6.5 30

M6 Light Ballast 20 30 2 0 4 2.5 7.5 30

M7 Ballast 15 90 2 180 4 1.5 5.5 30

M8 Ballast 20 90 2 180 4 2.5 6.5 30

M9 Ballast 20 30 2 180 4 2.5 7.5 30

M10 Light Ballast 15 90 2 180 4 1.5 5.5 30

M11 Light Ballast 20 90 2 180 4 2.5 6.5 30

Ponto de Madeira

M12 Light Ballast 20 30 2 180 4 2.5 7.5 30

Table 4.2 – Scenario Matrix

The manoeuvres required for arrivals at each port can be summarised as:



Tubarao Ponto de Madeira

- Course keeping during deceleration - Swinging - Backing into berth - Coming alongside

- Course keeping during deceleration - Steady turn / swinging - Coming alongside

The simulations were conducted by BMT’s experienced marine staff in a manner to enable

suitable comparison between specific manoeuvres for the two loading conditions.

Tugs were applied in the simulations to aid berthing and control of the ship. The available

tugs were determined from publically available information (e.g.

http://www.magioli.com/pmadeira.htm#P) and they were controlled using the PC Rembrandt

on-screens controls, applying normal nautical practice for the tug use. In the absence of

specific information, the tug sizes available for Tubarao were assumed to be the same as

Ponto de Madiera.

5 SIMULATION RESULTS

The full set of simulation results are presented in Appendix A.

To assess the differences between the manoeuvring capabilities of the typical Capesize bulk

carrier, it is possible to compare the results of standard manoeuvres such as the turning

circle or zig-zag in the same manner as conducted during the ships sea trials. This was not

the purpose of this study, but it is a well-know effect that as the trim of the vessel increases

by the stern, it becomes more dynamically stable ref [1], that is, it is harder to turn the ship and

the size of the turning radius increases although conversely it is generally easier to check

the yaw of the vessel.

For the purposes of this study, we have assessed the arrival manoeuvres at the ports of

Tubarao and Ponto de Madeira and analysed the results to derive an index that describes

the ability to manoeuvre the ship. Two indices are defined that allow us to present the

engine power and rudder angles used, as a function of certain critical value which were are

set as;

- Critical rudder angle = 20 degrees

- Critical engine rpm = 56 rpm (Half Ahead)

Where rudder angles over 20 degrees and engine orders greater than Half power are

required, it is felt that the manoeuvre has exceeded the limits of safe operation and there are

reduced safety margins.

As rudder effectiveness is directly linked to the use of the main engine (through the wake of

the propeller), the index to assess the manoeuvring ability is therefore defined as a multiple

of rudder and engine factors and allows the determination of a safety margin. It can be

defined as follows:

Ship Safety Index: ( )

( )CRITCRITCRIT

R

R

S

nn

nni

⋅⋅

⋅⋅=δ

δ ……… …………………………………….(i)



Where δR and δRCRIT are the applied and critical rudder angles respectively and n and nCRIT

are the applied and critical engine rpm values.

Where tugs are required to assist the manoeuvre, they too must have a margin of power in

order to respond to emergency situations and to allow for degradation of the effective bollard

pull with environmental conditions and ‘wear and tear’. A safety index for tug use is also

defined as follows:

Tug Margin Index: ( )( )MAX

TUG

TUG

T

P

Pi = …………………………………………………………….(ii)

Where PTUG and PTUGMAX are the applied tug power and maximum tug power respectively.

The results for these two indices should therefore be less than 1.0 for normal manoeuvring

and provide a means of assessing the relative requirements to safely manoeuvre using the

main engine, steering forces and tug control.

Table 5.1 presents the summary results for the simulations performed.

Run ID Loading

Condition

Maximum Sustained

Ship Index (iS)

Maximum Sustained

Tug Index (iT) Comments

Tubarao

T1 Normal Ballast 0.1 0.5

T4 Min Ballast 0.5 0.5

Min ballast vessel set’s down more under wind, is harder to keep in channel and keep course and cannot generate higher Rate Of Turn (ROT), hence higher ship index. Tug index equal as stern into wind and current zero in port.


T5 Min Ballast 0.25 0.5 As above.


T6 Min Ballast 1.0 1.0

ROT and ability to keep course about equal, but min ballast vessel is very hard to keep in channel due to set of wind. Max ship index for min ballast vessel and max tug usage, showing limits of operation.

Ponto de Madeira

M1 Normal Ballast 0.45 0.75

M4 Min Ballast 0.25 0.5

Min ballast vessel is harder to hold on track, but easier to bring alongside berth, hence lower ship index. Ability to turn is worse in certain wind angles – ‘jittery’. Normal ballast vessel is harder to berth hence higher tug index.



Harder to control drift of min ballast vessel, turning ability is worse at certain wind angles, hence higher tug index.



Easier to control yaw of min ballast vessel during approach and easier to move ship laterally in berth. Greater windage balances with current allowing controlled drift, hence ~ equal indices.



M7 Normal Ballast 0 0.75


Min ballast vessel swings quite easily, but loses headway very quickly. Normal ballast vessel is harder to move laterally onto berth, due to large wind turning moments, hence higher tug index. Higher ship index due to need to keep speed on hence higher RPM used.


M11 Min Ballast 0.15 0.5 As above


M12 Min Ballast 0.4 0.75 As above

Table 5.1 – Summary of Results

6 DISCUSSION

The results presented provide an assessment of the relative manoeuvring ability of a typical

Capesize bulk carrier in ‘normal’ and minimum ballast conditions. It was felt to be important

that this comparison be undertaken for realistic manoeuvres and the results for these are

presented in Section 5 above.

However, it is also important to understand the general effects that the use of the minimum

ballast condition has on vessel manoeuvrability. In general terms the minimum ballast

condition has a much reduced draught (and hence vessel displacement) and a large trim by

the stern. This can result in a reduced propeller immersion and less rudder area in the

water.

The general effect of the reduced draught (and displacement) is to reduce the inertia of the

vessel, which means that it will generate momentum much more easily to any stimulating

forces. On the positive side, this can result in a quicker response to steering forces or

engine power for example. However, it also means, that the vessel will generate momentum

much quicker under the action of the wind and to an extent, the current; although the effect

of current is much reduced due to the reduction in draught as there is less underwater area

to act upon.

The reduction in propeller immersion results in a reduced propeller thrust compared to the

propeller being fully immersed. Its performance will also be worsened by so-called aeration

whereby the action of the propeller blades coming out of the water, drags air onto the

propeller blade surface reducing its effectiveness. The reduction in rudder area in the water,

combined with the reduced capability of the propeller (producing reduced propeller wake)

reduces the steering forces that the rudder can apply.

The effect of the stern trim must be considered in conjunction with the effect of the reduced

draught and increased windage. With level trim, the windage has a ‘centre of effort’ (i.e. a

point at which the wind appears to act) that may be expected to be somewhere just aft of

midships as the distribution of area is mainly aft. With stern trim, there is a greater

proportion of the above water area forward and hence the ‘centre of effort’ moves forward

and may be ahead of midships.

For a vessel moving ahead with level trim, then the turning lever due to the windage and the

rudder is large, as both are far aft of the hydrodynamic pivot point which is typically 1/4 to 1/3



of the length aft of the bow when moving ahead (see Figure 6.1(a)). The hydrodynamic pivot

point may be thought of as the ‘centre of effort’ of the hull, although it is not fixed.

Figure 6.1(a) – Turning Levers in Level Trim Condition

With a large stern trim, the pivot point moves aft relative to its level trim position and hence

this reduces the turning lever that the rudder has, resulting in decreased turning

performance. In addition, the additional windage area forward moves the windage centre of

effort forward and this in turn reduces the turning lever the wind has and may even change

its direction (see Figure 6.1(b)).

Figure 6.1(b) – Turning Levers in Stern Trim Condition

The net result can generally be assumed to be a worsening of turning performance as

demonstrated in Figure 6.2 below. The reduction in turning lever of the wind with stern trim

also explains why the vessel in this condition will tend to drift bodily under the wind rather

than turning. This was especially apparent in a number of runs conducted for this study.

The greater windage area of the minimum ballast vessel was seen to result in lower ROT

and higher tug powers required to swing the vessel. The reduced displacement also leads

to a more ‘jerky’ response, whereby the vessel will quickly build momentum to any applied

forces (e.g. tugs, wind) and therefore needs careful control to ensure that large forces are

not allowed to be imparted for a significant length of time.

Whilst the majority of the effects of the minimum ballast condition can be seen to worsen the

vessels manoeuvring ability, there are some positive effects. The arrival manoeuvres into

Ponto de Madeira with a Southerly flowing current allowed the minimum ballast vessel to be

manoeuvred into the berth using a controlled descent technique with relatively little tug

power and use of the ships engines. This technique used the wind and current to swing the

vessel and drift it down onto the berth. This was not possible with the normal ballast

condition vessel as the wind does not cause a bodily drift, but tends to yaw the vessel

making the manoeuvre harder. This also affects the final stage of the manoeuvre when

bringing the vessel laterally alongside the berth.

R

R



Figure 6.2 – Comparison of Turning Performance for Normal and Minimum Ballast Conditions

7 CONCLUSIONS

Based on the analysis completed for this study, we can draw the following conclusions:

(i) The requirement for vessels to be in a minimum ballast condition results in a

number of significant effects to the manoeuvrability of the vessel.

(ii) These effects are generally characterised by;

a. Increased bodily drift under the action of wind due to the greater windage and

more even distribution of above water profile area along the vessel.

b. Increased difficulty in swinging the vessel at low or zero speed in significant

wind conditions due to the greater windage.

c. A more ‘jerky’ response to the actions of environmental (e.g. wind or current)

and control forces (e.g. tugs) due to the reduced displacement. This results

in the requirement for control forces (e.g. tugs, rudder etc) to be applied more

often and with lower power (i.e. a little and often) to minimise momentum

build up.

d. A worsening in turning performance when underway with a corresponding

increase in the ability to control yawing motions under certain wind directions

relative to the ships heading. This is due to the reduced turning lever as a

result of the large stern trim.

e. Increased loss of speed when heading into the current for a given engine

power due to the reduced displacement.

Normal Ballast Condition 957m

Min Ballast Condition 1390m



(iii) In all cases simulated as part of this study, tug powers of 50% or greater were

used consistently. In a number of cases, 75% or even 100% power was

required, indicating a reduction in safety margins for the manoeuvres. There was

no consistent pattern of higher tug power requirements between the two loading

conditions. This is due to the trade off between displacement and windage.

(iv) In almost all cases, the Ship Safety Index was higher for the minimum ballast

condition demonstrating that the minimum ballast condition required higher

engine power and rudder angles to maintain control and manoeuvre the vessel.

(v) In some cases, such as the action of wind or current from certain directions

relative to the ship, positive effects were experienced. These included the ability

to better balance the combined forces due to the wind and current, hence

increasing the ability to maintain course and track.

8 REFERENCES

[1] Principles of Naval Architecture; Volume III: Controllability, rev. 2. Ed. E.V. Lewis

SNAME Publication,1989.

[2] “SUMMARY OF VALE PORT REQUIREMENTS FOR VESSELS PRESENTED FOR

NOMINATION AND ACCEPTANCE FOR TRADING WITHIN VALE’S PORTS”,

available from www.vale.com.

[3] “Tubarão Port Information”; COMPANHIA VALE DO RIO DOCE PORT

OPERATIONS GENERAL MANAGEMENT, Sept 2004.



APPENDIX A – SIMULATION RESULTS



SIMULATION RESULTS - TUBARAO

Runs T1 and T4: Wind 10kts, 30 deg, current 1 kt, 225 deg

Figure A1: Track Plots for Runs T1 & T4

ROT with Time

-20

-15

-10

-5

0

5

10

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

ROT

[ °/m

in]

T1

T4

Manoeuvring Safety Index

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Safety Index

T1

T4

Figure A2(a): ROT Plots for Runs T1 & T4 Figure A2(b): Safety Index for Runs T1 & T4

Tug Bollard Pull with Time

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T1 Tug 1

T1 Tug 2

T1 Tug 3


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T4 Tug 1

T4 Tug 2

T4 Tug 3

Figure A2(c): Tug Index for Run T1 Figure A2(d): Tug Index for Run T4

T1

T1

WIND: 10kts

Current: 1kt 10kts





ROT with Time

-20

-15

-10

-5

0

5

10

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

ROT

[ °/m

in]

T2

T5


-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Safety Index

T2

T5

Figure A4(a): ROT Plots for Runs T2 & T5 Figure A4(b): Safety Index for Runs T2 & T5


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T2 Tug 1

T2 Tug 2

T2 Tug 3


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T5 Tug 1

T5 Tug 2

T5 Tug 3


T2

T2

WIND: 14kts

Current: 1kt 10kts





ROT with Time

-20

-15

-10

-5

0

5

10

15

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

ROT

[°/m

in]

T3

T6


-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Safety Index

T3

T6

Figure A6(a): ROT Plots for Runs T3 & T6 Figure A6(b): Safety Index for Runs T3 & T6 Tug Bollard Pull with Time

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T3 Tug 1

T3 Tug 2

T3 Tug 3


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

T6 Tug 1

T6 Tug 2

T6 Tug 3


T3

T3

WIND: 20kts

Current: 1kt 10kts



SIMULATION RESULTS – PONTO DE MADEIRA

Runs M1 and M4: Wind 15kts, 90 deg, current 2 kt, 180 deg

Figure A7: Track Plots for Runs M1 & M4

ROT with Time

-15

-10

-5

0

5

10

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24 01:40:48

Time

[hh:mm:ss]

ROT

[°/m

in]

M1

M4


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24 01:40:48

Time

[hh:mm:ss]

Safety Index

M1

M4

Figure A8(a): ROT Plots for Runs M1 & M4 Figure A8(b): Safety Index for Runs M1 & M4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M1 Tug 1

M1 Tug 2

M1 Tug 3

M1 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:14:24 00:28:48 00:43:12 00:57:36 01:12:00 01:26:24 01:40:48

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M4 Tug 1

M4 Tug 2

M4 Tug 3

M4 Tug 4

Figure A8(c): Tug Index for Run M1 Figure A8(d): Tug Index for Run M4

WIND: 15kts

Current: 2kts 10kts

M1

M1





ROT with Time

-30

-25

-20

-15

-10

-5

0

5

10

15

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

ROT

[ °/m

in]

M2

M5


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Safety Index

M2

M5

Figure A10(a): ROT Plots for Runs M2 & M5 Figure A10(b): Safety Index for Runs M2 & M5


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M2 Tug 1

M2 Tug 2

M2 Tug 3

M2 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36 01:04:48 01:12:00

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M5 Tug 1

M5 Tug 2

M5 Tug 3

M5 Tug 4


WIND: 20kts

Current: 2kts 10kts

M2

M2





ROT with Time

-30

-25

-20

-15

-10

-5

0

5

10

15

20

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

ROT

[ °/m

in]

M3

M6


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

Safety Index

M3

M6

Figure A12(a): ROT Plots for Runs M3 & M6 Figure A12(b): Safety Index for Runs M3 &

M6 Tug Bollard Pull with Time

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M3 Tug 1

M3 Tug 2

M3 Tug 3

M3 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M6 Tug 1

M6 Tug 2

M6 Tug 3

M6 Tug 4


WIND: 20kts

Current: 2kts 10kts

M3

M3





ROT with Time

-25

-20

-15

-10

-5

0

5

10

15

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

ROT

[ °/m

in]

M7

M10


-2.6

-2.4

-2.2

-2.0

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

Safety Index

M7

M10

Figure A12(a): ROT Plots for Runs M7 & 10 Figure A12(b): Safety Index for Runs M7 &


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24 00:57:36

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M7 Tug 1

M7 Tug 2

M7 Tug 3

M7 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M10 Tug 1

M10 Tug 2

M10 Tug 3

M10 Tug 4


WIND: 15kts

Current: 2kts 10kts

M7

M7





ROT with Time

-25

-20

-15

-10

-5

0

5

10

15

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24

Time

[hh:mm:ss]

ROT

[ °/m

in]

M8

M11


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24

Time

[hh:mm:ss]

Safety Index

M8

M11



-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M8 Tug 1

M8 Tug 2

M8 Tug 3

M8 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M11 Tug 1

M11 Tug 2

M11 Tug 3

M11 Tug 4


WIND: 20kts

Current: 2kts 10kts

M8

M8





ROT with Time

-20

-15

-10

-5

0

5

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

ROT

[ °/m

in]

M9

M12


-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

Safety Index

M9

M12



-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M9 Tug 1

M9 Tug 2

M9 Tug 3

M9 Tug 4


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12

Time

[hh:mm:ss]

Bollard Pull

[% of max.]

M12 Tug 1

M12 Tug 2

M12 Tug 3

M12 Tug 4


WIND: 20kts

Current: 2kts 10kts

M9

M9

Documents

Effect of the Minimum Ballast Condition on Bulk Carrier ... · Effect of the Minimum Ballast Condition on Bulk Carrier Manoeuvrability for INTERCARGO. A part of BMT in Maritime Transport