25. Guidelines for determination of economically efficient vessel characteristics and particulars for the commercial order for construction or purchase at the pre–owned market

It should be explained, that the methods of characteristics optimization by economic criteria are applicable for vessels (or other real assets as a part of marine company’s property complex) to an extent to which the object of optimization can be evaluated as the company’s property complex.
           Usually it can be referred to the marine commercial vessel if the difference of the vessel’s properties from the property complex are taken into account by the adjustment, for example, in addition to commercial vessel estimation to determine the working assets and to consider them in the general algorithm and if the number of variable of the vessel’s characteristics optimized by the economic criterion is not too great.
           When working out the model in details and increasing the number of varied characteristics, it becomes clear that many of characteristics are in functional interrelation, other, than the conformity of the optimality by the economic criterion.
           At preliminary stages of the investment planning after the estimation of the vessel main characteristics which are optimum from the economic point of view and correspond to the best values of the criterion (the left half of the scheme, fig. 25), as a first approximation it is required to determine a number of dependent characteristics and particulars to generate technical requirements for the vessel order for constructing or purchase.

 

Fig. 25. The economical optimality of the commercial vessel project characteristics
and particulars in the naval architecture and marine engineering systematic concept

Dependent vessel characteristics, as well as particulars can be determined on the basis of naval architecture calculations (the right half of the scheme, fig. 25) on the basis of the analysis of physical properties of the commercial vessel’s interaction with the marine environment (seaworthy properties), and also taking account of the internal properties of the commercial vessel design that is usually made after the investments are received at stages of the structural and technological design and it is not quite acceptable for the process of working out the investment project.
           In other words, the left part of the scheme on fig. 25 shows the determination of vessel characteristics by the economic criterion and this optimization method is called «an external subject», that at the same time the right party of the scheme shows – the determination of the commercial vessel particulars from the physical point of view that is «an internal subject».
           Since the external subject (the left part of the scheme) usually is solved by the investor – the shipping company which in the national relation gravitates to the ocean resources, and an internal subject (the right part of the scheme) is solved at the shipyard which most probably is located in the global industrial centre of East Asia, then, the condition of vessel characteristics optimality by the economic criterion which is structurally shown on the scheme, has an international sense.
           At preliminary design stages to determine the dependent characteristics and particulars when formulating the technical requirements for the vessel of the commercial order it is possible to use statistical dependences which approximately reflect developed parities between characteristics and particulars of an efficient, seaworthy and reliable vessel, safe in operation, strong and durable.
           According to system principles the independent characteristics of the vessel defined on the basis of optimization by the economic criterion, usually are chosen from the get out of number of the following ones: displacement D, displacement empty DP, cargo capacity PG and deadweight DW (considering, that from the listed four vessel characteristics usually two or three are dependent according to a certain degree of subject generalization), volume of vessel cargo holds W, total register tonnage GRT and net register tonnage NRT, power of main engine Ne, operational speed υ_S, etc.
           Usually at the phase of commercial vessel project optimization by the economic criterion from one to three or four characteristics vary, and depending on them other vessel characteristics and particulars are determined on the basis of design shipbuilding calculations or under empirical (statistical) formulas, and also on the basis of data of analogues use.
           Besides the independent characteristics determined by optimization by the economic criteria, in order to work out technical requirements for the vessel order it is necessary to determine also dependent characteristics and particulars such as: the commercial vessel dimensions, including waterline length LW, length over all L (or LOA); breadth B, draught TW at cargo waterline and depth H to the main deck (that is decks of impenetrable transverse bulkheads), and also, the factor of the general volume displacement δ– the ratio of commercial vessel volume displacement to multiplication of waterline length, breadth and draught at cargo waterline.
           The general recommendations concerning the characteristics and particulars in the order for vessels of widespread classes depending on the main characteristics which are preliminary determined by optimization by the economic criteria with the account the financial constrains of the investor or functional limitations are presented below.
           Besides, formulas which are presented in Chapter 25 for commercial vessel of corresponding class at a stage of data processing can be applied to check the compatibility of commercial vessel data or to additional determination of absent data, and also for the educational purposes when doing practical exercises – for vessel characteristics determination in learning tasks.
           The results of the given Chapter were studied with the participation of M.B. Bezuglova and M.V. Kovalenko under the author’s guidance.

Test questions

1. Applicability of methods of optimization by the economic criterion for determining the characteristics of the vessel (or other marine company asset).
           2. Dependent characteristics and particulars of vessel.
           3. Formation of technical requirements for the commercial order for vessel (or other marine company asset).

 

25.1. Correlation between of cargo vessel characteristics and particulars

The dependences between characteristics of marine cargo vessels (for example of a universal dry–cargo motor vessel and a commercial vessel for transportation of crude cargoes), between particulars, and also between characteristics, on the one hand, and particulars, on the other hand, are formalized on the basis of statistical generalizations and reflect developed parities between characteristics and particulars of an efficient, seaworthy and reliable vessel, safe in operation, strong and durable to an extent in which these properties are inherent in the used data of analogues.
           To determine the parities between characteristics for the commercial order of the universal dry–cargo vessel with displacement D (tonnes), cargo capacity PG (tonnes), deadweight DW (tonnes) and specification fuel stock Р_FL(tonnes) the results of statistical generalizations the following dependences can be recommended:

DW = 0.409 × D1.063, tonne;

(25.1)

PG = 0.232× D1,051, tonne;

(25.2)

РFL = 0.0015× D1.368, tonne.

(25.3)

The parities between the vessel characteristics for transportation of crude cargoes can be determined as:

DW = 0.477 × D1.043, tonne;

(25.4)

PG = 0.874 × D0.919, tonne;

(25.5)

РFL = 0.0015 × D1.338, tonne;

(25.6)

W = 0.493 × D1.05, cubic meters.

(25.7)

The regression dependences of characteristics on the design particular of the dry–cargo vessel – the waterline lengths LW (m) look like:

D = 0.583× LW1.945, tonne;

(25.8)

DP = 1.333 × LW1.501, tonne;

(25.9)

DW = 0.159 × LW2.149, tonne;

(25.10)

PG = 0.387 × LW1.81, tonne;

(25.11)

W = 0.031 × LW2.542, cubic meters;

(25.12)

GRT = 0.192 × LW2.058;

(25.13)

NRT = 0.0505 × LW2.152.

(25.14)

The dependences of vessel crude cargoes transportation characteristics on the waterline lengths LW (m), received on the basis of statistical generalizations, look like:

D = 0.181 × LW2.255, tonne;

(25.15)

DP = 0.11 × LW2.1, tonne;

(25.16)

DW = 0.087 × LW2.334, tonne;

(25.17)

PG = 0.322 ×LW1.946, tonne;

(25.18)

W = 0.076 × LW2.385, cubic meters;

(25.19)

GRT= 0.038 × LW2.445;

(25.20)

NRT = 0.023 × LW2.362.

(25.21)

To determine the design particulars and dimensions of the universal dry–cargo vessel for the commercial order it is possible to recommend the following statistical dependences:

LW / B = 2.814 × ln(LW) – 5.712;

(25.22)

B / TW = 0.0086 × LW + 2.535;

(25.23)

H / TW = 0.151 × LW 0.468;

(25.24)

LW / H = 8.812 × LW 0.16;

(25.25)

δ = 0.0016 × LW + 0.504.

(25.26)

It should be noted, that parities of commercial vessel dimensions and the factor of the general volume displacement also allow to use the equation of buoyancy  LW×B×TW×δ×1.025 = D(Archimedes’ law), to determine the displacement and further other characteristics according to formulas (25.1–25.7) at early design stages – before obtaining the investments into the project basic part – for the commercial order of the vessel.
           The recommended parities of dimensions and particulars of commercial vessel for transportation of crude cargoes for the commercial order:

LW / B = 2.013 × ln(LW) – 2.527;

(25.27)

B / TW = 0.469 – 0.0007 × LW;

(25.28)

H / TW = 0.59 × LW 0.174;

(25.29)

LW / H = 2.938 × LW 0.348;

(25.30)

δ= 0.0008 × LW + 0.689.

(25.31)

To determine ship main engine power Ne depending on displacement D (tonnes) the following regression formulas can be recommended:

– For universal dry–cargo vessel Ne= 0.418 ×D0.957, kW;	(25.32)
– For crude cargoes tanker Ne=  0.591 × D0.909, kW.	(25.33)

The determination of ship main engine power Ne according to formulas (25.32, 25.33) is based on the account of parametrical property of operational speed υ_S under the project of the cargo vessel that is specification speed, that can be explained as follows.
           In case of varying of vessel displacement D in the range from 100 to 100000 tonne the specification speed υ_Svaries within a substantially smaller interval by relative estimation, let us assume, from 14 to 20 knots, so it can be seen, that specification speed υ_Sis rather steady and invariable in comparison with an interval of variation of the design characteristic of vessel displacement D that is a parametrical property of the specification speed.
           The parities of the vessel design particulars determined by the formulas (25.22–25.31) possess the same parametrical property of stability with a rather narrow interval in case of variation of other characteristics, parameters and data.
           As the specification speed υ_Svaries within a substantially smaller interval than the displacement of vessel D at early stages of the vessel characteristics determination for the order there is a possibility to derive the speed out of data frameworks when determining the ship main engine power Ne and to determine power only depending on the vessel displacement D, considering thus, that speed υ_S is steadier, than displacement, and is also in dependence on displacement (that is speed is taken into account in formulas indirectly 25.32, 25.33).
           The reduction of factorial dimension of calculations using parametrical properties of some characteristics of the vessel and parities of particulars is of great importance at early stages of determination of vessel design characteristics for the commercial order, since it is possible to find characteristics and vessel particulars by means of consequently detailed calculation.
           The operational speed of the vessel υ_S according to the project (specification), in its turn, can be determined depending on waterline length LW which is connected with displacement D by the formulas (25.8, 25.15).
           The regression dependences of commercial vessel operational speed:

– For the universal dry–cargo vessel υS = 5.795 × LW0.142, knots.;

(25.34)

– For crude cargoes tanker υS = 2.33 × LW0.344, knots.

(25.35)

The formulas of the «Admiralty factors» Ne=υ_S^2.5×D^0.5/[c_ADM] for the determining of the commercial vessel main engine power Ne depending on displacement D (tonnes) and specification speeds υ_S (knots) when determining of factors [c_ADM] according to the statistic data look like:

– For the universal dry–cargo vessel Ne=υS2.5×D0.5/21.6 , kW;

(25.36)

– For crude cargoes tanker Ne=υS2.5×D0.5/21.9, kW.

(25.37)

Test questions

1. Parametrical properties of the commercial vessel dependent characteristics.
            2. Estimation for the commercial order of the commercial vessel displacement by the equation of the balance of loading depending on deadweight.

 

25.2. Dependences between characteristics and particulars of fishing vessel

After the phase of determination of independent characteristics according to the concepts of the systematic approach by optimization methods by the economic criterion it is required to estimate other characteristics – dependent, and also design particulars of the marine steel fishing vessel for the commercial order since usually there is only one independent characteristic from among the main ones such as: vessel displacement D, cargo capacity PG and deadweight DW in case of economic optimization at early stages of fishing vessel designing – before obtaining the basic investments.
           The other characteristics should be estimated by naval architecture methods of shipbuilding design calculation or according to statistical generalizations.
           If one characteristic of a fishing vessel from among specified above is determined by optimization methods by the economic criterion, other two characteristics can be calculated using of the equations of weight loading balance which are formalized by the statistical generalizations for vessels of the given class.
           The following equations of weight loading balance should be applied in order to determine the fishing vessel dependent characteristics from among number: vessel displacement D (tonnes), cargo capacity PG (tonnes) and deadweight DW (tonnes):

0.37×D-1.37×D1/2-DW=0;

(25.38)

0.40×D-0.68×D2/3-DW=0;

(25.39)

0.21×D-1.09×D1/2-PG=0.

(25.40)

The multipliers in the equations (25.38–6.40) concerning the characteristics of marine steel fishing vessels are the results of statistical generalizations and selection.
           Also the parity between displacementD (tonnes) and project (specification) deadweightDW (tonnes) of the fishing vessel for the commercial order (if one of these characteristics is determined by optimization methods by the economic criterion, and the second characteristic is in dependence on the first one) can be found by solving the equation of weight loading balance which is not only the result of statistical generalization, but also includes the use of the weight factor 0.0 < a< 1.0, which characterizes expert preference of the entering balance equation in the form of (25.38) in relation to the equation (25.39):

(0.37÷0.40)×D - α×1.37×D1/2 - (1-α)×0.68×D2/3 - DW = 0.

(25.41)

The regression dependences of other characteristics and particulars on displacementD (tonnes) and waterline lengths LW (m) of the fishing vessel look like:

W/PG = 6.03×D-0.122cubic meter / tonne – specific tonnage;

(25.42)

GRT=0.385×D1.074;

(25.43)

NRT=0.127×D1.071;

(25.44)

W=0.42×D1.003 , cubic meters;

(25.45)

D=0.113×LW2.394, tonne;

(25.46)

DW=0.0228×LW2.515, tonne;

(25.47)

PG=0.0066×LW2.67, tonne;

(25.48)

W=0.0514×LW2.407 , cubic meters;;

(25.49)

GRT=0.035×LW2.60;

(25.50)

NRT=0.0126×LW2.569.

(25.51)

The recommended parities of fishing vessel dimensions depending on waterline length LW (m) for the commercial order are:

– The relative length of a fishing vessel in dependence on waterline length LW/B=1.93 × ln(LW) - 2.93;

(25.52)

– The relative breadth of fishing vessel B/TW = 0.0039×LW + 2.38;

(25.53)

– The height of fishing vessel board H to the main deck H=0.40×LW 0.68, m ;

(25.54)

– The height of fishing vessel board HD to main deck HD=1.24×LW 0.50 , m;

(25.55)

– The relation of fishing vessel length LW to height H of the board to main deck LW/H=2.50×LW 0.32;

(25.56)

– The relation of fishing vessel length LW to height HD of the board LW/HD=0.81×LW 0.50;

(25.57)

– The relation of height H of the board to the fishing vessel main deck H/TW=0.92×LW 0.10;

(25.58)

– The relation of height HD of the board to fishing vessel upper deck to draught TW in cargo HD/TW=1.18×LW 0.09;

(25.59)

– The factor of the general volume displacement δ = 0.0016×LW + 0.504.

(25.60)

The recommended statistical dependences to calculate the main engine power on displacement D (tonnes) for fishing vessel commercial order are follows:

– The power of fishing vessel’s main engine Ne=3.57×D0.81 , kW;

(25.61)

– The total power of fishing vessel auxiliary engines Nu=3.98×D0.66 , kW;

(25.62)

– The formula of the «Admiralty factors» by the results of statistical data generalizations Ne=νS2.5×D1/2/15.5, kW.

(25.63)

To estimate the daily running fuel expenditure depending on main engine power Ne (kW) the following empirical dependence can be recommended

q1=0.008×Ne0.946, tonne / day.

(25.64)

The statistical dependence of fishing vessel operational speed υ_S on waterline length LW (m)

νS=3.17×LW0.346, knots.

(25.65)

Concerning vessels of other classes, except considered above: the universal dry–cargo vessel, the tanker for crude cargoes transportation and the marine steel fishing vessel, that is for vessels with other set of classification attributes (see paragraph 1.1), for example, for rolling cargo vessels, ferries, container cargo vessels, bulk cargo vessels, vessels for transportation of wood cargoes, towing vessels, icebreakers, not self–propelled (barges) etc., – it can be recommended to apply statistics accumulation, working out and use of the analogues regression formulas for project characteristics and particulars estimation – the dimensions and their parities.
           When constructing a new vessel, including the project stage, the estimation of her characteristics, dimensions and their parities under statistical formulas (25.1–25.65 or similar according to vessel class) can be a source of data for the further specification of characteristics and dimensions by the methods of naval architecture and shipbuilding design calculations for the initial approximation.
           Also the determination of characteristics and dimensions of a commercial vessel can be a method of quality supervision of constructing from the part of the investor. For this purpose, the investor should estimate optimal characteristics and dimensions as the basis to make the decision on vessel construction, and the probable deviations revealed at a stage of acceptance of the constructed vessel from the set of predetermined characteristics should be defined for the commercial order for construction as the basis for preliminary stipulated concessions of purchase price (reproduction cost).
           When planning the commercial vessel purchase at the pre–owned market, and also in a value estimation the essential difference of her characteristics, dimensions and their parities from the statistical values defined by the formulas (25.1–25.65) can be a sign of functional depreciation – surplus or a lack of one particular or property or another and the basis for purchase price concession.

Test questions

1. Independence of variable for optimization by the economic criterion and interrelation between the fishing vessel main characteristics: displacement, cargo capacity and deadweight.
            2. Additional determination of fishing vessel dependent characteristics by the balance equation, the variants of fishing vessel balance equation.
            3. General recommendations concerning determination of dependent characteristics of commercial vessels of various classes with accumulation and use of statistical data.
            4. Estimation of characteristics and particulars for the control of the quality of construction from the part of investor.
            5. Application of the values of dependent characteristics and the particulars of commercial vessel, determined statistically, for estimation of functional depreciation and purchase price concessions.