International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 5

Number 3

September 2011

315

1 INTRODUCTION

On optimizing a harbour lay-out, the relationship be-

tween changes in the lay-out, and the resulting

changes in flow, wave pattern and the ship’s path,

should be reproduced as well as possible. In such

cases, if small-scale modelling is required, the

choice of a physical-model study of the port and ad-

jacent sea area is used. A current or wave-pattern is

generated to reproduce local conditions as well as

possible. This is the case of SIAMA (Analogical

Manoeuvring Simulator) of the Hydraulic Laborato-

ry Harbour and Coastal Division of the São Paulo

University, Brazil, which has been fully operational

since December 1993. This Brazilian hydraulic cen-

tre has clients among governmental and private or-

ganisations, maritime authority (Brazilian Navy),

port authorities and pilots.

Unfortunately, the risks involved in full-scale

measurement, as a research technique, do not permit

intense investigation of hazardous manoeuvres in

confined channels. Furthermore, full-scale meas-

urement can be undertaken only in existing situa-

tions. Excluding field tests, which, besides the high

risk involved, are far too expensive, manning mod-

els, although requiring large areas, are ideal for

training in shiphandling, especially of low-speed

control without tug assistance. Real-time simulator

studies in a Full Mission Bridge Simulator, although

of extreme importance in the design process, only

provide limited design-option evaluation, due to

costs and time-consuming if multiple manoeuvre

scenarios are to be covered. Consequently only a

limited part of pilot experience and knowledge is

used for assessing always too few of these options.

The SIAMA analogical concept, with ships and

tugs unmanned, is a reliable cost-effective way of

combining nautical studies with the hydraulic runs

usual in scale-model port-study projects. In fact, this

fast-time facility permits running a large amount of

test statistics under various desirable environmental

conditions (bathymetry, winds, waves, tides and cur-

rents), for different vessels and project lay-outs over

a limited period.

The aim was to highlight the convincing useful-

ness of SIAMA, based on more than 1500 official

recorded tests in almost 20 years of existence, and

Analogical Manoeuvring Simulator with

Remote Pilot Control for Port Design and

Operation Improvement

P. Alfredini

Escola Politécnica da USP, Sao Paulo, Brazil;Instituto Mauá de Tecnologia, Sao Caetano do

Sul, Brazil

J. P. Gerent

Escola Politécnica da USP, Sao Paulo, Brazil

E. Arasaki

Escola Politécnica da USP, Sao Paulo, Brazil; Instituto Nacional de Pesquisas Espaciais, S. J.

Campos, Brazil

ABSTRACT: The use of an Analogical Simulator in shiphandling-manoeuvre tests (SIAMA) in waterways

constitutes a useful tool for providing improvements in port design and manoeuvring rules, which, when en-

hanced with other relevant hydraulic studies of Froudian scale models, is a source of valuable statistical in-

formation. The time-scale of physical models fast-time runs complie with the square root of the linear scale,

in this study-case the model time was 13.04 times faster than prototype. More than 1500 official tests having

been undertaken since 1993 by 13 official pilots of three harbours, for manoeuvring and project optimization

in 7 piers, with 10 berths, and radio-controlled ore carriers of 75,000, 152,000, 276,000 365,000, 400,000 and

615,000 dwt. The laboratory facilities belong to the Escola Politécnica of Sao Paulo University, Brazil. The

port area studied comprised fairways, turning basins and berths. The ships and tugs were unmanned, with tug

performance exerted by air fans.

316

different case-studies, thereby encouraging its use in

providing information and reducing the number of

runs of a Full Mission Bridge Simulator. The ports

studied are located in São Marcos Bay (Brazilian

north coast): VALE Ponta da Madeira Maritime

Terminal (PDM), which is the second in annul load-

ing rate in Latin America (figures 100 Mt) with four

piers and seven berths, ALUMAR Harbour (2

berths) and Itaqui Harbour (1 berth) were all studied

at this facility.

2 ENVIRONMENTAL CONDITIONS

In Figure 1, it is possible to visualize a tidal current

pattern validated through SIAMA. These are diffi-

cult conditions for approaching manoeuvres to PDM

Pier II, since external currents are greater than those

in the confined inner basin. According to Alfredini

et al. (2006) and Alfredini et al. (2008), high tidal

currents, due to tidal ranges up to 6.5 m, are present

in the harbour site studied. The wave-climate is less

important, with maximum heights of 1.0 m.

3 DESCRIPTION OF METHODS

The hydraulic model of SIAMA consists of a down-

scaled undistorted 1:170 model with 1100 m

of the

geometry of an estuarine area, in which tidal cur-

rents can be generated. In Figure 2A there is an aeri-

al view of VALE PDM Piers I and III (South and

North Berths).

Through the simulator, an attempt is made to sail

a radio-controlled ship-model along a desired track,

with a scenario similar to that in the prototype (see

Fig. 2B), reproducing port facilities and navigation

aids. Wind effects are provided by fans and tugboat

force by air propellers mounted inside the hull of the

ship model itself (see Figs 2C an 2D). The ship is

steered by pilot-control from ashore (Fig. 2E), using

radio-controlled rotating cameras mounted in posi-

tion on the ship-model bridge (Fig. 2F). Thus, an in-

correct visual picture of the waterway can, to a cer-

tain extent, be corrected. Since both the vessel and

tugs are unmanned, the SIAMA concept is an ana-

logical simulation modeling technique. Furthermore,

there is the problem of time: the application of

Froude’s law to determine scaling factors is required

in order to correctly represent total hydraulic influ-

ence. This implies that the time-scaling factor is

equal to the square root of the linear-scaling factor.

Thus, in the model, time will pass faster than in real

life (13.04 times in SIAMA). This, depending on the

difficulties arising from the quickness of the real

manoeuvre, can be a hinderance to the model’s pilot.

Thus, an apprenticeship for pilot adaptation becomes

necessary.

Tests to determine the effect of current forces on

the navigation of vessels at port approaches are car-

ried out at SIAMA, by using radio-controlled ships

in hydraulic models. Control is exerted over one or

two propellers and the ship’s rudder. Tug force,

when required, are simulated by the thrust of ducted

air fans. Six variable speed fans, rigidly fastened in-

side the hull of the model ship, blow from windows

opening thereon (see Fig. 2D). These are located at

the bow and stern (longitudinal forces), fore star-

board and portside (transversal fore forces), and aft

starboard and portside (transversal aft forces). Each

fan has an independent speed control, the maximum

thrust being 750 kN (prototype). Engine and tugs

speeds are calibrated according to prototype data,

thereby providing dead slow, slow, half, full ahead,

and reverse. In Figure 2G, one can see the propeller

and rudder at the stern of a Panamax (75000 dwt)

vessel model.

During a test run at SIAMA, a pilot manoeuvres

the ship along a variety of courses using any of the

available combination of forces. His orders are

transmitted by radio communication (Fig. 2E) to a

staff controlling tug force, engine speed and rudder

angle (see Fig. 2H). Commands are transmitted by

radio (see Fig. 2I) to a servo-mechanism on board

the vessel model. Simultaneously, photographs are

taken from overhead at timed intervals (see Fig. 2J),

and video records made by cameras (overhead, ves-

sel-bridge and port). These records show the posi-

tion and orientation of the ship, as well as the set-

tings of all controls. A later analysis of these records

reveals, for example, how tugs need to be used to as-

sist the passage of the ship through the prevailing

currents, or whether the forces applied have exceed-

ed those available in practice. Films produced of

phenomena occurring in hydraulic models can be

shown at reduced speed to enable a true comparison

with the full-scale object.

The SIAMA facility has models of ore carriers of

75,000, 152,000, 276,000 365,000, 400,000 and

615,000 dwt. The model-calibration procedure in-

cludes turning circle tests compared with prototype

data. In Figure 2K, one can see this procedure for a

Panamax (75,000 dwt) vessel.

The tests were undertaken by the ports’ pilots,

with the co-operation and assistance of senior mem-

bers of the marine departments of the companies

concerned. This involved manoeuvres for berthing

or departure under various tidal conditions.

317

Figure 1. Tidal current conditions validated by SIAMA, for the end of extreme spring flood equinoctial tidal-range conditions, at

Ponta da Madeira.

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Figure 2. (A) Aerial view of VALE PDM Piers I and III (South and North Berths); (B) SIAMA run of a tug assisted manoeuvre at

VALE PDM Pier III. Starboard berthing manoeuvre with a ballast Panamax-class ore carrier (75,000 dwt); (C) Tug assisted ma-

noeuvre at VALE PDM Pier III starboard berthing manoeuvre with a ballast Capesize; (D) Window for an air fan blowing into the

Capesize-class ore carrier (152,000 dwt) model hull at fore portside. The calibrated effect reproduces the pushing activity shown in

Figure (C); (E) SIAMA run of a tug-assisted approaching manoeuvre for the starboard berthing of a ballast Capesize-class ore carri-

er (152,000 dwt) at VALE PDM Pier III. One can observe pilot vision from the bridge starboard micro-camera and his radio control

device for remote rotating of the camera and for changing the image from the starboard (F) to the portside camera. Orders are also

given by radio to tug-masters and engine/rudder (G) SIAMA controlling staff in another room (H); (F) Panamax-class ore carrier

(75,000 dwt) vessel model. One can observe the rotating camera mounted in starboard position on the ship-model bridge; (G) Pan-

amax-class ore carrier (75,000 dwt) vessel model stern. One can observe the propeller and rudder; (H) SIAMA controlling staff; (I)

The SIAMA radio device; (J) Overhead sequence of photographs of the final stages of a VALE PDM Pier III (North Berth) star-

board berthing of a ballast Panamax-class ore carrier (75,000 dwt); (K) SIAMA run turning circle calibration test for a Panamax-

class ore carrier (75,000 dwt); (L) View of the gauges mounted on the VALE PDM Pier III North Berth for fender deformation

measurement; (M) SIAMA recording of berthing conditions (test showed in J), given by fender deformation in the prototype (in

cm), versus manoeuvring prototype time for VALE Pier III (North Berth) fenders;

319

In Figure 2, certain features of SIAMA devices

are described (for further details see Alfredini et al.

2008). The similarities between bridge manoeuvring

vision and prototype conditions are shown. An im-

portant issue regarding efficient berthing manou-

vring is berthing force impact, or the equivalent

fender deformation, which is measured in gauges

(accuracy of 0,01 mm) rigidly mounted into the deck

of the pier (see Fig. 2L). Fender stiffness is scaled

down by steel blades calibrated according to proto-

type specifications. The evaluation of impact force

in SIAMA runs is used either as an input for fender

projects or for pilot training purposes. A graph illus-

trating deformation in four fenders in a berthing test,

is shown in Figure 2M.

Another interesting possibility is to study the

conditions of night manoeuvres, since all luminous

navigation aids are scaled, so as to comply with the

flash time and colors of beacons, warning lights,

lighthouses, vessel lights and port lights.

4 SOME RESULTS AND ANALYSIS

The results of some case studies with SIAMA are

hereafter presented with details.

The exceptional conditions with a fairly high lev-

el of risk are to be studied: prevailing environmental

conditions, the general situation of traffic and fail-

ures. Initially, the risk is related to the degree of cir-

cumstantial difficulties in the conditions for

manoeuvring, e.g. a strong wind, waves and cur-

rents. Final risks are related to malfunction in proce-

dures and communications, (misunderstanding, mis-

calculation and lack of attention) and technical

malfunction (engine, rudder, or tug failures). The

consequences, due to the probability of such initial

events producing an accident (contact, collision,

grounding, etc.) are damage, loss of lives, environ-

mental impacts, etc.

Figure 3 contains a detailed description of the

manoeuvring run of a ballast Capesize-class ore car-

rier (152,000 dwt), for approach and berthing to

PDM Pier II, solely with tug assistance, thereby

simulating the loss of both engine and rudder. The

channel is strongly confined by PDM South Groin

(jetty) and the shoals of an island and tidal currents

conditions are difficult (see Figure 1). This serves as

an example of the usefulness in evaluating the risks

of hits or groundings involved in the failure of

equipment, such as engine, rudder or tugs, in this

case the engine and rudder. As described by Al-

fredini et al. (2008) and Gerent (2010), for each set

of runs the peer group fills in a check-list based up-

on PIANC et al. 1997, for a de-briefing and open

discussion of the following itens:

1 Tug Activity: number of tugs and orders, as well

as force employed.

2 Engine Movements: frequency, number.

3 Assessment line and position maintenance: ability

to keep the vessel to the intended track, and to as-

sess its position.

4 Position: with relation to the pier and other ships.

5 Control and Safety: feeling of “in control”

throughout: feeling of safety.

The following scores were attributed to each

item:

10 - practicable, with ease and adequacy

5 - conditionally practicable with certain difficulty

0 – barely practicable

A Pairwise Comparison is obtained, based on this

traditional questionnaire. The result of the compari-

son of every possible pair of alternatives gives a

ranking of condition scenarios, viz., much easier,

easier, as difficult as, more difficult than and much

more difficult than.

From Figure 4, it is possible to gain a quantitative

idea regarding the economic impact of a manoeu-

vring study. In the present case, the results provided

an enlargement of daily tidal windows from 6 to 14

hours, with the consensus of a joint group of mari-

ners, engineers and the Brazilian Naval Authority.

This study involved all the 13 official pilots, the port

captain and naval officers. With the improvements

thus obtained, it is now possible to undertake com-

bined manoeuvres (the coordinated approach and

berthing of one vessel and the departure of another),

by using two additional tugs with more bollard pull

(750 kN) than the existing 500 kN. The SIAMA is

prepared to make these concomitant manoeuvres

with two pilots, with two sets of controls for two

vessels. The immediate consequence of this optimi-

zation was an increase of 15% in the annual loading

rate (equivalent to 10 Mt of iron ore).

Summarizing, SIAMA fast-time simulations

comprised the study of more than 400 runs for PDM

Pier III, more than 350 for PDM Pier I, more than

300 for the future PDM Pier IV, more than 200 for

PDM Pier II, more than 100 for ALUMAR Harbour

and more than 50 for Itaqui Harbour. Also important

for these statistics was the ideal pilot adaptability to,

and familiarisation and cooperation with, SIAMA

features. In fact, all the runs were 13.04 times faster,

according to the SIAMA Froude law of similitude.

As regards the latter, it was also possible to reach a

fine balance in the number of runs carried out by

each of the official pilots (more than 100 manoeu-

vres in average). Only under these conditions was it

possible to obtain a change in the official manoeu-

vring rules of the Naval Authorities.

320

5 CONCLUSIONS

Hydraulic scale-models have an extensive range of

application, and it is quite possible that the model of

a harbour or river-section is already being built to

predict hydrodynamic patterns, pollutant dispersion,

mooring conditions, silting, the general arrangement

of jetties and breakwaters, etc. In such a case, the

choice is whether it is worthwhile to use existing

hydraulic models for manoeuvring investigation,

that is the SIAMA concept.

An important aspect in design is the lay-out and

dimensions of the harbour itself, as well as those of

approach channels and turning basins. Harbour effi-

ciency and safety is defined by its nautical accessi-

bility and/or capacity, and hence, economic viability.

The strategic dimensioning lay-out and operational-

entrance windows in the early design phase can be

optimized by fast-time simulations, as those with the

SIAMA analogic concept.

In addition to its application as a training tool,

SIAMA also facilitates risk analysis in a compara-

tive sense, as a tool for port design. Nevertheless,

the main reason for its use is the assistance in simu-

lating the behaviour of those in charge of manoeu-

vring procedures, normally extremely difficult to

simulate in mathematical or other descriptive mod-

els. Furthermore, results from fast-time simulator

experiments can be incorporated into probabilistic

design.

The results presented confirm the possibility of

using the SIAMA concept as an cot-effective tool in

optimizing port designs, as well as developing the

empirical data sets required to sustain further devel-

opments in the investigation of manoeuvrability.

ACKNOWLEDGEMENTS

The authors wish to thank the support from USP and

Instituto Mauá. Thanks are also due to Vale. Special

recognition is mainly due to MSc in Hydraulic En-

gineering and Master Mariner Captain Joffre Villote,

former professor of the Brazilian Ship Simulator,

and after PDM Port Captain and Nautical Special

Advisor of VALE, for his continuous and encourag-

ing wisdom, and for obtaining the necessary confi-

dence in teamwork, of pilots, masters, tug masters

and officers, thus making our task easier.

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Figure 3. Example of SIAMA run detailed description of a ballast Capesize class ore carrier (152,000 dwt) approaching manoeuvre

and berthing at PDM Pier II only with tug assistance, simulating a loss of engine and rudder.

322

Figure 4. The enlarged tidal windows obtained at SIAMA for PDM Piers I and III. The manoeuvring tidal window was enlarged

from 6 to 14 hours daily, thus improving berth simultaneous manoeuvring. The port loading rate increased by 10 million t|year, a

15% improvement