report on cost estimation research vessel
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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
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COST ESTIMATION TECHNIQES IN SHIPBUILDING
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
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COST ESTIMATION TECHNIQES IN SHIPBUILDING
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
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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
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COST ESTIMATION TECHNIQES IN SHIPBUILDING
Dividing both we get a factor of 1.442 which is multiplied with steel ,outfit labour and material costs respectively
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COST ESTIMATION TECHNIQES IN SHIPBUILDING
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
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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
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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
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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 £
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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
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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
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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 £
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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 £
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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.)
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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)
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b) Stabilisers
CST = £331Δ3/4
CST-cost at mid '77 rates(£)
-Volume displ. In tonnes.Δ
Total stabiliser costs = 231020.84 £
(Assuming 20 % escalation)
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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
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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.
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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
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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.)
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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
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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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