International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 5

Number 2

June 2011

241

1 INTRODUCTION

The manoeuvre of ships turning is executed every

time during the ships presence in the port and it is

one of the often port manoeuvres. The influences on

the size of turning basin during the manoeuvre have

the large quantity of factors.

The turning basin has two meanings. First mean-

ing is the manoeuvring basin delimited by the

manoeuvring ships, second is the hydro-technical

building artificial or natural with suitable horizontal

and vertical dimensions, where the considerable al-

terations of the course of the ship are executed. Ob-

viously, the turnings over are practices „in the

place”. This should be understand as the change of

the course of the ship whose linear speeds, during

the manoeuvre, are close to zero. Turning the ship

over is done on the turning basin as a result of the

planned tactics of manoeuvring and can be done on

itself or in co-operation with tugs or use of anchors

or spring lines. All dimensions of turning basin as

the hydro technical building has to be larger than the

turning basin understood as the manoeuvre basin to

avoid the collision with bottom or bank (Kornacki

2007).

The simulating method of designing the parame-

ters of turning basins are based on series of tests in

comparable conditions on prepared model of reser-

voir and the model of the ship planned to use the

turning basin. The results of tests are subjected the

statistical processing. Effect of that kind of research

is delimitation of the area of manoeuvring on the

turning basin according to the various foundations of

hydro meteorological conditions, various parameters

of ships and various levels of the trust. Characteristic

feature of the simulating method is that simulating

models of the ship manoeuvring are especially de-

signed to the solved problem.

Figure 1. The example of tests of simulating of turning ma-

noeuvres.

The material in the result of simulating investiga-

tions comes into very large sizes, which is subjected

Simulating Method of Ship’s Turning-basins

Designing

J. Kornacki

Szczecin Maritime University, Szczecin, Poland

ABSTRACT: The paper presents one of the methods of ship’s turning-basins designing. The simulating

method is more and more often used to the defining parameters projected turning-basins, testing of existing

turning-basins and the improving of the manoeuvring practice on the particular manoeuvring basin.

242

far processing. The application of the methods

which will let process got results to the form ena-

bling making far analysis necessary is. The area of

manoeuvring of the ship is the basic criterion of the

analysis of the results of simulating testing’s, and the

dimensions of this area are it numerical coefficient.

The variety of the elements of the system of the port

and narrow waters causes that various methods are

applied. These methods are characterized limitations

and conditions. The method of parallel sections, sec-

tor method and polar method are complies with

marking the dimensions of the basins of manoeu-

vring of the ship in simulating investigations (Guz-

iewicz & Ślączka, 1997).

2 DELIMITING THE BASIN OF

MANOEUVRING OF THE SHIP ON THE

TURNING BASIN

The methods of delimitation of the area of manoeu-

vring of the ship are based on the suitable division of

the water areas of manoeuvring and the engagement

of suitable point or the axis of the reference. For the

needs of delimitation of the manoeuvring area on the

turning basin and during the manoeuvres of the turn-

ing of the ship the polar method is engaged. This

method differs from the method of parallel sections

that the sections are replaced by sectors and the axis

of the reference is replaced by the point of reference.

The difference in the relation to the sector method

depends in the engagement of the point of reference

not outside but inside the area of manoeuvring and

the division of the manoeuvring basin on sectors

hugging the round angle.

The polar method in the principle is the change of

the sector method. Co-ordinates of points mark the

area of manoeuvring ship are qualified in the polar

co-ordinates. Then, knowing the exact position of

the point of the reference, they are easy to proceed-

ing in the far analysis. Wanting delimit the manoeu-

vring basin in the polar method, the studied

manoeuvring area should split on the sectors of the

delimited width Δ α.

The selection of the proper width of the sector es-

sential is. The width of the sector simplifying should

fulfil dependence (Guziewicz & Ślączka, 1997):

( )

××−

××

〉∆

180sin

[⁰] (1)

where:

∆

- width of the sector [⁰],

- length over all [m],

- acute angle contained among the longitudinal

axis of the symmetry of the ship and the secant of

definite sector [⁰],

- the number of extreme points on one board de-

scribing the waterline of floatation [-],

- the ray of the projected turning basin [m],

Figure 2. The split of the manoeuvring area in the polar meth-

od.

The selection of the width of the sector is de-

pendent from the received suitable number of the ex-

treme points of the ship. This influences on the size

the error steps out among the delimited area of the

manoeuvre and real manoeuvring area left by the

ship.

One can express this error in the approximation

(Guziewicz & Ślączka, 1997):

360

cos

βαδ

×××∆=

iSi

[m] (2)

where:

- error of delimiting manoeuvring basin [m],

∆

- width of the sector [⁰],

- the ray of the projected turning basin [m],

243

- acute angle contained among the longitudinal

axis of the symmetry of the ship and the secant of

definite sector [⁰],

Figure 3. The error of delimiting manoeuvring basin.

During the test data with the course of the ship,

shape of the waterline of floatation and the co-

ordinates of geometrical centre of the waterline of

floatation are recorded. The co-ordinates of extreme

points of the ship are calculated in the polar co-

ordinates.

Figure 4. The extreme points of the ship on one particular wa-

terline.

Distances d

of the extreme points of ship from

the point of the reference are calculated, where i is

the number of the extreme points of the ship describ-

ing the waterline of flotation. The table of the dis-

tance D

[k, s, d

] in which counted distances d

are

assigned to sectors s for individual simulating tests k

is created.

Based on the table of the distance D

[k, s, d

] the

tables of maximum distances D

S max

[k, s, d

i max

] and

minimum distances D

S min

[k, s, d

i min

] of extreme

points of ship waterline from the point of reference

in every sector of basin for every simulating test are

created. This makes possible the assignment the line

of movement of the ship in the single test.

Figure 5. The line of movement of the ship in the single test.

Based on the table of maximum distances D

S max

[k, s, d

i max

] and minimum distances D

S min

[k, s, d

min

] and the suitable statistical model of the expan-

sion of maximum and minimum distances, the co-

ordinates of points of the area of manoeuvring with

the assumption of level of the trust are appointed in

separate sectors.

244

Figure 6. The line of movement and manoeuvring area of the

ship.

3 THE PRACTICAL USE OF THE

SIMULATING INVESTIGATIONS

3.1 The practical use of the polar method

The polar method can be applied to the preparation

of the measuring data to the statistical processing

during real investigations. Error resulting from the

applied method of delimitation the line of movement

in this case is enlarged by error resulting from the

measurement and error resulting from the prepara-

tion of the measuring data to the use of the polar

method becomes.

In the case of use of the polar method, while de-

limiting the manoeuvring basin of ship in simulating

investigations, the results are burdened the only er-

ror the applied method.

In the practice, the simulating method complies

in two aims. First, it complies in the qualification of

sizes of the planned turning basin. Second, it com-

plies in the qualification of maximum permissible

sizes of ships can safely use the turning basin.

The turning basin is safe for the ships manoeu-

vring, if every her sizes in the horizontal plane and

perpendicular plane are larger than the sizes of the

manoeuvring area traced by the manoeuvring ship. It

is mean that on the whole area the safe under keel

clearance and the safe distance from banks and

slopes has to be kept.

The analysis of the results of simulating tests

leads to measuring the parameters of manoeuvring

area, which means the qualification of the parame-

ters of the horizontal safe manoeuvring area.

Figures 7 and 8 present the vertical and the hor-

izontal section view of turning basin.

Figure 7. The turning basin – the vertical view.

Figure 8. The turning basin – the horizontal view.

During simulating investigation relevant to the

turning basin, it is important to take into considera-

tion also the expansion of the speed of propeller

streams, the expansion of directions of propeller

streams, and influence of the every kind of hydro-

technical buildings, slopes and banks on the ship

(Galor, W. 2002).

manoeuvring area

line of movement

245

3.2 The examples of use of the simulating

investigations

Figures 9, 10 and 11 present the examples of results

of simulating investigation of typical turning ma-

noeuvre.

Figure 9. The manoeuvring areas with different trust levels dur-

ing turning manoeuvres.

Figure 10. The manoeuvring areas with different trust levels

during turning manoeuvres.

Figure 11. The manoeuvring areas with different trust levels

during turning manoeuvres.

Figures 12, 13, 14 and 15 present the examples of

results of simulating investigation on real port water

areas (Kornacki, J.& Galor, W. 2007).

Figure 12. The north turning basin investigation in port of

Świnoujście (

The unpublished report 2000).

Figure 13. The south (BPP) turning basin investigation in port

of Świnoujście (

The unpublished report 1995a).

Figure 14. The turning basin investigation in port of Kołobrzeg

(

The unpublished report 1995b).

Figure 15. The turning basin investigation in port of Police

(

The unpublished report 1998).

ships turning basin

-100

-80

-60

-40

-20

100

-250 -200 -150 -100 -50 0 50 100 150

max

min

95%

ships turning basin

-150

-100

-50

100

150

-250 -200 -150 -100 -50 0 50 100

max

min

95%

ships turning basin

-100

-50

100

150

-250 -200 -150 -100 -50 0 50 100 150 200 250

max

min

95%

246

These examples are showing scale of use of the

simulating investigations. Base on the northern turn-

ing basin in Świnoujście, the problem of the analysis

of the turning basin can be present.

The northern turning basin in Świnoujście was

investigated several times, usually in the context of

considerations on the subject of the possibility of

manoeuvring in the harbour of the “maximum”

ships. Problem this came back because of the devel-

opment of the harbour in Świnoujście and the ambi-

tions of the service larger ships. In the years 1995-97

was made one of first analyses in the aspect of the

possible modernization of the northern turning basin.

The investigation was made then to qualify possibili-

ties of the entry the ships about the total length 255

m into the harbour. The qualification of the possibil-

ity of the safe turn of ships on the northern turning

basin was one of the elements of these investiga-

tions. The eventuality of the increase of the sizes of

the turning basin was taken into the consideration

then so that ships do not violate the infrastructure of

the western bank of Świna. In the year 2001, the

problem was returned when the possibility of enter-

ing into the harbour of the ships of total length 260

m were study again. The investigations were led

with the assumption that the existing bathymetry of

the port’s reservoir will not be changed. In the year

2003, the possibility of the entry the ships of total

length to 280 m with new tugboat „Uran” was ana-

lysed.

4 CONCLUSIONS

The methods of delimiting the area of manoeuvring

basin of the ship depend on the suitable split of the

manoeuvring area. Polar method should be applied

to marking manoeuvring area on turning basin.

The polar method is based on the suitable split of

the manoeuvring area, the engagement of the point

of reference and proper random variable to assign-

ment of this basin. The distance of points describing

the waterline of the ship from the point of the refer-

ence is the applied universally random variable.

The taken value of the width of the sector in the

polar method has the direct influence on the value of

the error among the real line of the movement of the

ship and the line of movement of the ship delimited

the polar method.

Main advantage of the simulating method is the

possibility of the exact qualification of the manoeu-

vring area. Through the far statistical analysis of

many tests, the ready information of the sizes of the

basin which the ship needs to the realization of the

manoeuvre of the turning is available.

Very important advantage of the simulating

method is relatively low cost of investigation.

Often, navigational obstructions mark the acces-

sible manoeuvring basin. It has the influence on the

way of manoeuvring. The use of the simulation al-

lows optimizing sizes of such basin or the way of

manoeuvring.

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