report on cost estimation research vessel

COST ESTIMATION TECHNIQES IN SHIPBUILDING

REPORT ON COST ESTIMATION OF

O.R.V SAGAR KANYA

SCHOOL OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING

INDIAN MARITIME UNIVERSITY

VISHAKAPATNAM CAMPUS

PROJECT GUIDE SUBMITTED BY

Sri U.S RAMESH PRAMOD K.B

CHIEF MANAGER,SMDR M-TECH (NA-OE)

VISHAKAPATNAM 2011-13 BATCH

IMU-VISHAKAPATNAM CAMPUS


OBJECTIVE:

The main objective of the project is to estimate the cost of construction of the given vessel from the empirical formulae recommended by J Carreyette. and analyse for an optimal technique for cost estimation during design stage of a Ship.

Name of Vessel : O.R.V SAGAR KANYA

Operator : National Centre for Antarctic and Ocean Research (NCAOR)

Owner : Ministry of Earth Sciences ,Government of India.

Date of commission : March 1983

Vessel Parameters

Length over all 100.34 mLength ,LBP 89 m

Breadth overall 16.39 mDepth to main deck 9.8 m

Draught 5.6 mMass displacement 1554.5 tonnes

Gross Tonnage 4209 RTNet Tonnage 1029 RT

Vol.displacement 1516.585 m3

Engine Electric propulsion 2x1230 kwSpeed 14.25 knots

Endurance 45 days/10,000 nautical miles



Introduction

In recent years, there is severe competition in the shipbuilding industry due to the increased shipbuilding capacity compared with demand. The shipbuilding yard has to deal with a highly variable product that makes bid-

ding on contracts very difficult. The pricing for new shipbuilding could have a high risk especially with minimal profit margins and precious little time available. To reduce such risk in estimation, there should be a quick and accurate means to accomplish reasonable and

reliable cost estimate method.

Cost is concerned with how much money the shipbuilder will pay for shipyard labour to build the ship ,subcontractors to assist ,all materials and equipment contained in the completed vessel, miscellaneous services and establishment charges.

Methodology



Compensated Gross tonnage

The Compensated Gross Tonnage, CGT, is considered as a worldwide yardstick for shipyard output in commercial shipbuilding replacing the traditional measures, manhours/tonne steel weight, and this concept have been developed from 1960s.This coefficient reflects the amount of work necessary to produce that particular type and size of ship.One gross ton of a passenger ship, for example, with its sophisticated accommodation and public spaces, contains a significantly greater level of work content than one gross ton of a bulk carrier which is effectively little more than a large steel box with an engine on the back.One CGT of either ship on the other hand should contain roughly equivalent work content.The system has now been highly developed and is fundamental to the analysis of shipbuilding activity.

For a general cargo vessel

CGTCARGO = 27* (4209^0.64)

= 5634.278

For Research vessel (NCCV)

CGTR.V = 46* (4209^0.62)

= 8123



Dividing both we get a factor of 1.442 which is multiplied with steel ,outfit labour and material costs respectively



1) Labour costs

The estimation of labour man-hours for ship production is considered an important item during the early stage of negotiation before signing the contract. With few information about the ship during the preliminary design stage, it is necessary to apply a good prediction method for estimating the ship production man-hours

If H- man hours x - size variable -constantα n<=1

H=αxn

a) Steel work manhours

If Rh-actual man hours per tonne of net steelCb-block coefficient at laden summer draught



Ws-net steelweight in tonnesL-LBP in metresA'-factor from table 1

Rh= A' / [Cb(Ws/L)1/3]

Table 1

Average wage rate Overheads

of direct labour £/hr 75% 100% 125%1.6 700 800 9002 875 1000 1125

2.4 1050 1200 1350

A plot of' A' for different wage ratesAssuming overheads as 100% ,value of A' was plotted as shown and for a

wage rate of 3.78 €/hr, A' was obtained to be 3580

Total steelwork labour costs



H = RhWs = A'*Ws2/3L1/3 / Cb

= 3580 × 1.442×24482/3 × 891/3/ 0.5798 = 10015617£

Determination of Cb,Steel weight,outfit weight and machinery weight is given in APPENDIX 1.

b) Outfit labour cost

Assuming no subcontracting,We have

Co1=C'Wo2/3

Where Co1-total cost of outfit labour

C'-factor given in table 2

Wo-outfit weight,tonnes

Table 2

Average wage rate Overheadsof direct labour £/hr 75% 100% 125%

1.6 8350 9550 107502 10425 11925 13425

2.4 12500 14300 16100



A plot of' C' for different wage rates

From this corresponding to a wage rate of 7.16 £/hr value of C'=42677

Total outfit labour costs = 42677× 628.09 2/3

= 6260023.6 £



c) Machinery Installation labour cost

Assuming no subcontracting,We have

CM1=F'P0.82

CM1-total cost of Machinery installation labourF'-factor given in table 3P-Service propulsive horsepower

Table 3

Average wage rate Overheads

of direct labour £/hr 75% 100% 125%1.6 323 369 4152 404 461 519

2.4 485 553 622

A plot of' F' for different wage rates

From this corresponding to a wage rate of 7.16 £/hr value of F'=1650



Total Machinery Installation costs = 1650 ×1.15× 3058 0.82

= 1368861.62 £

(Accounting 15% increase for twin screw ships.)

2) Material costsa) Steel material costs

Csm=B'Ws

CsM-total steel material cost

B'-factor given in table 4

Ws-net steelweight,tonnes

Table 4

Average price of Wastage +welding rodsshipbuilding steel £/tonne 8% 10% 13%

150 178 182 186200 237 242 248250 296 303 310



A plot of' B' for different prices of steel

From this corresponding to a steel rate of 146 £/tonne value of B'=181.2

Total steel material costs = 181.2× 2448.582

Total steel material costs = 889922 £



b) Outfit material costs

Com=D'Wo0.95

CoM-total steel material cost

D'-factor given in table 5

Wo-outfit weight,tonnes

Table 5

DATE D'Jun-75 1500Jun-76 1725Jun-77 2011

Taking linear extrapolation in june 1983

D'= 3550

Total outfit material costs = 3231334.99 £



c) Machinery cost

CM=G'P0.82

CM-total cost of Machinery

G'-factor given in table 6

P-Service propulsive horsepower

Table 6

DATE G'Jun-75 735Jun-76 845Jun-77 980

Taking linear extrapolation in june 1983

F'= 1715

Total Machinery Installation costs = 1422396.5 £

(Accounting 15% increase for twin screw ships.)



3) Additional cost

a) Thrusters

CT=£48000+35000Tt

CT-cost at mid '77 rates£

Tt-thrust in tonnes

Total thruster costs = 389820.35 £

(Assuming 20 % escalation)



b) Stabilisers

CST = £331Δ3/4

CST-cost at mid '77 rates(£)

-Volume displ. In tonnes.Δ

Total stabiliser costs = 231020.84 £

(Assuming 20 % escalation)



Total cost of Vessel

The total cost of ship is defined as follows:

Total cost = Total Labour cost + Total material cost

Where

Total Labour cost = Direct Labour cost + Overheads +Profit

And

Total Materials cost = Suppliers’ cost + Handling and wastage + Profit



Total cost = 23808897 £

= 36903945.42 र (INR) (thirty seven million approximately)

Assumptions

Vessel is built with 75%-85% Grade 'A' steel and remaining B,E,AH,DH or EH.No other material like Aluminium is accounted for.

No part of the ship is built by subcontracters

Overheads are taken to be 100% and profit as 10%.

Complexity of construction in steelwork is neglected.

This estimate does not take into account research equipment onboard or special cargo handling devices,winches etc.

No life cycle costs have been considered.



APPENDIX 1.

Determination of block coefficient Cb

We Know Mass Displacement

=L×B×T×CΔ b× ×1.005ƿ

SoCb = /(L ×B×T × ×1.005)Δ ƿ

= 4855/(89×16.39×5.6×1.025×1.005)

= 0.5798

Steel Weight:

Watson & Gilfan.

= 2267.2

= 2342.32

Where K- constant for different vessels E- Hull numeral



k= 0.045 for research vessels.

E=L(B+T)+0.85L(D-T)+0.85(l1*h1)+0.75*(l2*h2)

= 2937.421

=0.2934

Optimising. and taking 8% margin for scrap weight.

Wst= 2448.582 tonnes

Machinery Weight:

Wm = (0.98) BHP / 10 + 200 - Munrosmith

=437.08 tons = 414.4 tonne

( Taking 10% more for twin screw engines.)



Total Outfit Weight:

Outfit weight is divided into outfit and hull eqipment weight

outfit weight is calculated as follows

WO = Co (CN/1000)0.825

where Co = 2103 (A constant between 2103 & 2412) H. BenfordCN - cubic number = (L×B×D/1000)

= 422.54 tonnes

Hull equipment weight is calculated as follows

WHE = CHE(CN/1000)0.825

where CHE = 1023 (A constant between 1023 & 1196) H. BenfordCN - cubic number = (L×B×D/1000)

= 205.54 tonnes

Total outfit weight= 628.04 tonnes



REFERENCES

1) J. Carreyette- ‘Priliminary ship cost estimation’,RINA,19772) Mishra S.C - ‘Priliminary Ship Design’,IMU-Visakhapatnam3) Ahmad .M.Rashwan – ‘Estimation of ship Production

manhours’,Alexandria university,Egypt.4) Watson,D.G.M and GILFILLAN,A.W.:’Some Ship Design

Methods’.Trans.RINA,Vol 119,1977,p 279.5) R. Munro-Smith –‘Elements of shıp desıgn’, (1975-1995)6) H. Schneekluth and V. Bertram- ‘Ship Design for Efficiency and

Economy’,1998.

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