identification of trade-offs. The example shows how the trade-off between purchase and acquisition cost and operating cost results in the lowest life cycle cost.


4. VESSEL CHARACTERISTICS AND SYSTEM DEFINITION


The vessel used as an example herein is a high speed ferry designed using three different material concepts:


 The steel version consists of a steel hull and an aluminium superstructure.


 The aluminium version is an all aluminium version.  The composite version is a sandwich construction with faces made of multiaxial carbon fibre reinforcement and vinyl-ester matrix, and structural foam core material (Divinycell)


Table 1 Main characteristics, identical for all three vessel concepts Length overall


Breadth, maximum


Draught, maximum


128.00 m 19.00 m


3.33 m


Passengers 1000 Operating range 300 nautical miles Speed


42 kn


Cargo capacity Case A: 250 cars / 35 motorbikes Case B: 102 cars / 220 trailers


Table 2: Weight split-up based on Aker Finnyards data sheets


Hull


Superstructure Painting


Hull and deck outfitting


Interior and panelling


Thermal insulation Fire insulation Machinery


Electrical power distribution and lighting


Steel version (tonnes) 940 120 12


Aluminium version (tonnes)


470 110 10


250 230 133 130


35


485 55


Total 2030 40


380 55


1425


Composite version (tonnes)


607 10


230 130


0 27


380 55


1439


To reach the required speed of 42 knots, the machinery types listed in table 3 are used. Due to the lighter weight of the aluminium and composite version, the two diesel engines are omitted.


Table 3: Machinery, *two additional diesel engines are required on the steel ship Number


Type


2 Gas turbine


2 Diesel engine*


GE LM2500 MTU 20V1163 6500


The main physical difference between the different versions is their weight. The actual weights for the various components of both steel and aluminium version are based on the data sheets from Aker Finnyards [1]. For the composite


version the weight of hull and


superstructure has been derived from the preliminary design study. As the structural weight of the aluminium and composite version are similar, it is assumed that the same type of engine can be used for the two versions. Furthermore,


outfitting, interior


the weight of and


panelling,


painting, hull and deck electrical power


distribution and lighting are assumed to be the same for both lightweight structures. However, weight savings due to the unnecessary thermal insulation in the composite version are taken into account.


In order to gain a fair comparison of costs and energy requirements, the following assumptions are stated:


 No investment costs in additional infrastructure due to technology adaptation of a manufacturer is considered.


 The life span of all three versions is set to 25 years, although the technical life spans are expected to differ one from each other. However, a calculation of LCC using varied life spans would distort the result of this study.


 For the hourly rate of manufacturing and engineering average values are taken. This is because the data from the collaborating companies differ due to their locations and may not be published.


 All cost and energy elements, which are identical or similar, are not taken into account; Outfitting, Painting, Electrical power supply and distribution, Crew wages, Harbour and channel dues, Loading and discharging, Classification, Insurance and administration.


The operation is split up into three modes: operation in summer, operation in winter, and maintenance.


Summer (May – Sept) 18 h/day Winter (Oct – April) 12 h/day January


Specification Power in kW at 100 % 22000


Maintenance, yearly docking


During summer and winter operation, the ferry is running its machinery at the following time and proportions:


power


©2008: Royal Institution of Naval Architects


B-3


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