Design of an ultra deep water drillship with crude oil storage capacity type I

Design of an ultra deep-water drillship

with crude oil storage capacity type I

TU Delft report nr. OvS 98/10

Design of

an

ultra deep-water drillship

with crude oil storage capacity

TU Delft

1!1 i

$,

_kg.

0'

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..774,1 ;i1, 14.:11:40 ;41.46 4.4. le age

btZel.: Off'

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Type

'GUSTO

ENGINEERING

1

Design of an ultra deep-water drillshipk

with crude oil storage capacity

TYPE I

E.F.J. van Leeuwen

M. Spilker

TU Delft, Maritieme "Techniek

Supervisor: Jr. H. Boonstra

Professor: Prof. Jr. A. Aalbers

Report nr. OvS 98/10

IHC Gusto Engineering BV

Supervisor: Ir. J. Lusthof

.

Document nr. 6204.1000.303

Schiedam, 1998

Lt.

'U Delft

-

GUSTO

ENGINEERING

Preface

This report forms part of our graduation work at TU Delft, Maritieme Techniek. The

entire work is performed by order of IHC Gusto Engineering BV.

This report contains a design study of a modem drillship.

We acknowledge the many engineers at Gusto Engineering, particularly those of the

naval architectural design department for their enthusiastic support. We clearly

wouldn't have come so far without them. Much credit goes to Ir. Boonstra from Delft

University of technology for running the offshore department at the faculty where

offshore belongs: Maritieme Techniek!

Schiedam, June 25 1998

E.F.J. van Leeuwen

Introduction

As a response to the huge demand for deep-water drillships, this report contains the

design of a DP drillship with storage capacity.

Special attention was paid to minimisation of main particulars, with regard to a

requirement of a free deck area of 500 m2.

This ship has a working name Free decker.

In chapter one some design considerations are given, accompanied by a rough

description of lay out and performances. In the other chapters all relevant aspects of

the design, such as stability, DP-system and hull strength are discussed.

The design is based on specifications formulated by IHC Gusto Engineering BV and

TU Delft. Those requirements can be found on the following pages.

GUSTO

ENGINEERING

De afstudeerders zullen ieder afzonderlijk een dynamisch gepositioneerd diep water boorschip

met olie opslag capaciteit ontwerpen met inachtneming van de relevante gedeeltes van het

cursuswerk.

Het ontwerp zal de volgende scheepsbouwkundige aspecten omvatten:

Ontwerp aspecten:

Weerstand en voortstuwing

Electrisch vermogen

Downtime (vereenvoudigd)

Grootspant

Veiligheid

Bouwprijs berekening

Waterdiepte

Boordiepte

single line diagram

elektrische balans

scheepsbewegingen

indeling / lay-out

De te ontwerpen schepen moeten voldoen aan de volgende eisen:

Gemeenschappeliike ontwerpeisen:

Order

Fax no.

Date

Page

Hs

6.0 m

Tp

10-13 sec

V,,nd

25.0 m/sec

Vcurrent 1.1 m/sec

Stand-By (Riser disconnected)

Hs

10.0 m

Tp

15-18 sec

Vwind

30.0 m/sec

Vcurrent 1.1 m/sec

Transit, wereldwijd

10.000 ft

30.000 ft onder rotary

:

6204

4-Jun-98

2

Klassificatie

DNV

DP notatie Dynpos AUTRO

Operationeel gebied

Wereldwijd, nadruk op:

GOM

Brazilie

West-Afrika

Omgeving condities

Max. drilling

Stabiliteit berekening

intact

lek

Langsscheepse sterkte

Dynamisch postioneren

thruster lay-out

omgevingskrachten:

wind

stroming

golven

capability plots

-GUSTO

ENGINEERING

Afzonderliike ontwerpeisen:

Schtp 1

Derrick

Vrij dek oppervlak

Order

Fax no.

Date

Page

conventioneel (54' x 54' x 190')

hookload 726 t

500 m2

6204

4-Jun-98

3

Bij het ontwerp van schip 1 zal speciale aandacht besteedt worden aan een minimale

hoofdafmetingen vergroting ten gevolge van de vrije dekoppervlak eis.

Schip 2

Derrick

nieuw ontwerp, by. Huisman

ltrec Dual Mast

hookload 726 t

Vrij dek oppervlak

geen eis

Bij het ontwerp van schip 2 zal speciale aandacht besteedt worden aan de logistiek m.b.t.

riser, en drillpipe handling en opslag.

Crude Oil

100.000 bbls

Brine

2 x 700 m3

Mud

1750 m3 totaal

Silo's

12 x 60 m3

Base Oil

300 m3

Drilling Water2000 m3

Bulk (zakken)

400t

Risers, tubulars, casing, drillpipes volgens

water- en boordiepte

Setback

Riser tensioning

8 x 2 tensioners, totaal 1162 t

Crude Oil Productie

20.000 bbls/dag

Crude overslag

stern offloading

Accommodatie

150 man

min. 12.5 kn, proeftocht

Opslag capaciteit

Consumables voor 90 dagen operatie

:

Scheepssnelheid

TABLE OF CONTENTS

Design considerations

3

1.1 Principal dimensions

3

1.2 Hullform

3

1.3 General arrangement

4

.3.1 Lay-out

4

.3.2 DP system

4

.3.3 Accommodation

5

.3.4 Production facilities

5

.3.5 Engine rooms

5

.3.6 Deck cranes

5

.3.7 Volumes

6

1.4 Drilling equipment and logistics

6

1.4.1 Pipe storage

7

2 Intact stability

8

2.1 Introduction

8

2.2 Stability requirements

8

2.3 Loading conditions

9

2.3.1 Summary of loading conditions

10

2.4 Wind heeling moment curves

10

2.4.1 General

10

2.4.2 Calculation of wind heeling moment curves

10

2.4.3 Results

11

2.5 Results of intact stability calculations

11

2.5.1 Extra pay-load on free deck area

11

3 Damage stability

12

3.1 Requirements

12

3.2 Results

13

4 Resistance and propulsion

14

4.1 General

14

4.2 Resistance

14

4.3 Thrusters for main propulsion and DP

14

4.4 Results

15

5 DP Station keeping

16

5.1 DP-requirements

16

5.2 Thruster system

16

5.3 Environmental forces

17

5.3.1 Wave drift forces

17

5.3.2 Current forces

18

5.3.3 Wind forces

19

5.3.4 Riser force

20

TYPE I

FREE DECKER

5.4 Thruster forces and consumed power

20

5.4.1 General

20

5.4.2 Environmental conditions

20

5.4.3 Intact thruster system

21

5.4.4 DYNPOS AUTR failure

21

5.4.5 DYNPOS AUTRO failure

21

5.4.6 Total power balance

22

6 Power generation and distribution system

23

6.1 Power generation

23

6.2 Power distribution system

23

6.3 Load balance

24

7 Down time

25

7.1 Motions

25

7.2 Downtime

25

8 Hull strength

27

8.1 Loadings

27

8.2 Midship section

27

8.3 Results

28

8.3.1 Material

9 Hull weight

29

10 Building price

32

Appendix

33

TYPE I

FREE DECKER

28

2

1 Design considerations

1.1 Principal dimensions

The principal dimensions are determined by using a concept exploration model. A full

description of this model can be found in report "Design aspects of an ultra

deep-water drillship with storage capacity". By selecting a large breadth, possible future

modifications of the vessel are accounted for in ways of stability.

This leads to the following main dimensions:

1.2 Hullform

The following choices have/been made regarding the hullform:

Wide cylindrical

/

aped bow to accommodate thruster.

Large midship section to reduce fabrication costs.

Pram-formadship, which will provide

a good flow to the main propulsion

thrusters.

V-form shaped foreship to obtain good motion characteristics.

appendages:

S\61k.

Scheg to increase directional stability and to ease dry-docking of the vessel.

Bilge keels to restrict roll motion.

On the following pages a body plan and a lines plan can be found.

,R9)71'

Length overall

205,2 m

Length between perpendiculars

192,0m

Breadth

35,0 m

Depth at side

18,0 m

Design draft

9,0 m

Displacement

50.000 tri-i

Depth at cellar deck

10 m

TYPE I

3

FREE DECKER

s

FREE DECKER

5.6

10.8

15.0

Breadth Cm) 1/150

I

\

is;

.Breadth Cm) 1/150

FREE DECKER

'S_fl

IA

.

1S

.

0

0.0

2

If

5

6

7

onam deck level 18 re

8

nes

pLc

9

10

lore castle deck121.1

11, lie 11 12 13 11. 15 16 17 18 19 20

Principal dimensions

Length between perpendiculars

192,0 m Length overall 205.2 m Breadth 35,0 in Depth 18.0 in

Draught transit Cb at transit draught

0,80

0

3

1.3 General arrangement

1.3.1 Lay-out

As drilling is the main activity of the vessel, positioning of all drilling equipment has

been given first priority. Short lines and free access to the drilling area benefits to

high drilling efficiency. All piping is stored above main deck, in front of the drillfloor.

Consequently, the moonpool is situated relatively far aft.

Below deck level, two crude oil tanks occupy the space between the drilling area and

the accommodation area. These tanks have a total capacity of over 100.000 bbls. Aft

of the moonpool the mud tanks and mud pumps are situated below deck level for

increased stability. There is a large free deck area of over 500m2 directly aft of the

derrick, this deck area can for instance be used for coiled-tubing equipment or a

gravel pack.

For reasons of safety the accommodation is placed at the fore ship.The power

generation set, production module and ground flare are placed downwind of the

drilling area and accommodation. A rough subdivision in function groups can be

found below. A general arrangement can be found in appendix 1 and drawing

nr.

6204.0001.304

6204.0001.306.

1.3.2 DP system

The vessel will be dynamically positioned by means of two azimuthing thrusters at

the stern and four azimuthing retractable thrusters below keelplane level. All thrusters

are installed in containerised units with a retraction system (appendix 1) to retract

them above waterline level or even main deck level for major overhaul. The deck

above the thrusters has been kept free.

The DP system fulfils DNV DYNPOS AUTRO requirements. A complete redundant

system for power generation, power distribution, controls and thrust generation is

applied.

TYPE I

₄

FREE DECKER

101710201. 50.11.01112012 r

0.471:c

Jed/

Drilling equipment

Accommodation

1.3.3 Accommodation

The accommodation block is designed to quarter a total of 150 persons. The cabins

are placed above main deck level. The most upper deck accommodates the

navigational bridge. Furthermore, two decks are in use for supporting services and

equipment, such as: mess room, offices, stores, galley, recreation room, laundry, etc.

The accommodation will be situated in the foreship just aft of the collision bulkhead.

The length of the accommodation block is 27m, the maximum breadth 24m.

1.3.4 Production facilities

The production facilities, intended to perform extended well tests and early

production, will be accommodated on a raised platform on top of the main deck, near

the stern. The dimensions of the platform are: 20m x 25m. It is designed for a

throughput of up to 20.000 bbls/day. At this flowrate, the vessel is able to produce

five days uninterrupted, before offloading.

The production platform is able to cover the following functions:

Separation of crude oil, produced water and gas.

Treatment of oily water to satisfy the applicable code requirements for dumping.

Export metering.

1.3.5 Engine rooms

The vessel has two completely separated engine rooms, to satisfy DYNPOS-AUTRO

requirements. Each engine room contains 4 generator sets of 5200 kW each

(alternator output at MCR).

1.3.6 Deck cranes

Three pedestal cranes will be installed on the vessel on main deck level to load,

unload and handle drillpipes, casing, risers or other weights. The capacity of all three

cranes is 20 ton at 35 m, or

5 ton at 25,5 m.

TYPE I

5

1.3.7 Volumes

'In the table F.

the total tank capacities can be found..

Tank capacities

Table 1.1.,

1.4 Drilling equipment and logistics

The vessel is equipped with a conventional derrick with a top; mounted heave

compensator, top drive and a vertical racking system. The derrick will be

approximately 58m. (190') high, and 16,5 x 16,5 m. wide. The height of the drill floor

is 12m. above main deck, the BOP can be handled with a skidding system from the

cellar deck in front of the derrick to position underneath the drill floor.

The christmas tree can be assembled, tested and handled on a cellar deck aft of the

derrick.

Loads on derrick and drillfloor:

Static hookload max.

726t

is

_{Setback max.}

_650t

Riser tensioning

8x2 tensioners, total load a 162t.

Volume (me)

1

Mud

'

2.120

Brine

1.840

Drilling water

1

2.110

'Base oil'

350

MDO

5.600

!Crude

16.025

; Sloptank

610

Potable water

1.090

water ballast

I

15.000

;

TYPE I

6

FREE DECKER

1.4.1 Pipe storage

All piping is stored in front of the derrick, consequently all pipe handling takes place

in front of the derrick, the aft side is kept free for the possible installation of coiled

tubing equipment.

All pipe handling will be taken care of by means of overhead cranes and a dragway.

The overhead cranes pick up the pipes, riser joints or casing joints from their

horizontal racks and lay them down onto the dragway. This system provides high

operability with regard to ship motions. Overview pictures of the pipe area can be

found on the next pages. The capacities of the pipe racks can be found in table 1.2.

Pipe storage area

Figure 1.1.

Pipe storage capacities

Table 1.2.

Casing 30"

Riser 211" drilling

)--)k_ 1

I Length (m)

'Casing 30"

200 m

Casing 20"

800 m

Casing 13" 3/8

2.000 m

Casing 9"5/8

3.500 m

Drillpipe 5"

i

9.200 m

I Drillpipe 5" landing string

3.100 m

Drillpipe 3" workover

9.000 m

I Drillcollar 7"

1.100 m

Riser 21" drilling__

3.500 m

Riser 7" completion

3.000 m

Tubing 7" tie back

3.500 m

'L

TYPE

₇

FREE DECKER

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2 Intact stability

2.1 Introduction

The intact stability of the vessel is investigated for seven relevant loading conditions.

Three fundamentally different operations can be recognised:

Transit operation

Drilling mode

Testing mode

Furthermore, a loading condition is defined to examine the stability characteristics

during survival conditions.

2.2 Stability requirements

The applicable stability criteria of the vessel have been summarised below. The

criteria are as per the DNV Rules for classification of Steel ships, DNV Rules for

Mobile Offshore Units and the IMO MODU CODE.

The applicable stability criteria are:

The maximum righting arm should occur at an angle of heel preferably exceeding

30° but not less than 25°.

The righting lever GZ should be at least 0,20 in at an angle of heel equal to or

greater than 30°.

The area under the righting lever curve (GZ) up to an angle of heel of 30° should

not be less than 0,055 mrad.

The area under the righting lever curve (GZ)up to an angle of heel of 40° should

not be less than 0,090 mrad. or the angle of flooding Of if this angle is less than

40°.

The area under the righting lever curve (GZ) between the angles of heel of 30° and

40' or between 30° and Of if this angle is less than 40°, should not be less than

0,030 mrad.

The initial metacentric height GM° should not be less than 0,15 m.

The area under the righting lever curve (GZ) to the second intercept or

downflooding angle, whichever is less, should be not less than 40% in excess of

the area under the wind heeling curve to the same limiting angle.

The range of the righting lever curve (GZ) should be at least 30°.

The angle of second intercept between wind heeling lever and righting lever

should be at least 30°.

TYPE

8

FREE DECKER

2.

1.

4.

51.

I

2.3 Loading conditions

Relevant loading cases are drawn from a typical well program. The following stages

can be recognised:

Move vessel on to location

Drill 36" hole to 1.000 ft below seabed

Run & cement 30" casing

Drill 26" hole to 2.000 ft below seabed

Run & cement 20" casing

Install 18-3/4 BOP and riser

Drill 16" hole to 9.000 ft below seabed

Run & cement 13"318 casing

Drill 12"1/4 hole to 15.000 ft below seabed

Run & cement 9"5/8 casing

Drill 8"1/2 hole to 20.000 ft below seabed

Run & cement 7" liner

Disconnect BOP and riser

Run X-mas tree & 7" completion riser

Well testing

Plug & suspend well

Sailing home

Emergency disconnect LMRP during drilling or test

The following loading cases are defined:

Condition

Well program stage

1

Sailing 90% consumables

1

2

Sailing 10% consumables

16,17

3

Drilling, BOP connected, 90% consumables

2 12

4

Drilling, BOP connected, 10% consumables

, _ 17

Testing 90% consumables, 98% crude storage

13,14,15

6

Testing 50% consumables, 50% crude storage

13 14,15

7

Testing 10% consumables, 98% crude storage

13,14,15

8

Survival condition, 10% consumables

18

TYPE I

9

FREE DECKER

t.

2.3.1 Summary

of

loading conditions

In all loading conditions taking in ballast water has minimised the trim of the vessel.

2.4 Wind heeling moment curves

2.4.1 General

The wind heeling moment curves are based on the guidelines presented in the IMO

MODU Code and DNV Rules for Mobile Offshore Units (part3, ch.2, sec.6).

In the guidelines two wind conditions are defined for intact stability. For offshore

service conditions a minimum wind velocity of vc = 36 mis should be applied, and a

minimum velocity of vc = 51,5 m/s is defined for severe storm conditions. For loading

condition 1 to 7 (sailing, drilling, testing) the wind velocity of 36 m/s is used and for

survival conditions (cond.8) the wind velocity of 51.5 m/s is used.

2.4.2 Calculation of wind heeling moment curves

The wind heeling moment curves as required by the rules have to be transformed in

such a manner so that they can be implemented in PIAS.

The wind heeling moments in PIAS are based on the wind contour of the vessel.

Because the only input required for the calculations is the windpressure, this value has

been adjusted for the shape and height coefficient to obtain the wind heeling moments

defined by the Rules for the, various sections. In appendix 2 the windpressures at the

different levels for the different conditions used in the stability calculations are

presented.

For the various draughts formally the change of the height coefficient has to be taken

into account. P1AS takes the influence of the change of the area for the hull for the

different draught into account but neglects the change of the height coefficient. The

deviations due to this method are very small and neglected. At smaller draughts the

wind heeling moment will be calculated a bit too small and for larger draughts a bit

too high. The calculation of the heeling moments can be found in appendix 2.

TYPE I

10

FREE DECKER

Loading condition

1

2

3

4

5

6

7

8

Displacement (t)

47359

35260

47159

40799

55741

49639

47976

38318

Draught (in)

8,824

6,810

8,589

7,571

9,960

9,001

8,748

7,176

Trim (m)

0,076

0,090

-.0,562

-0,306

0,075

0,205

0.756

0,484

VCG (m)

12,40

14,18

11,863

13,31

12.35

11.60

13,96

13,71

LCG (m)

97,62

99,37

96,56

97.85

96.82

97.73

99.00

99,91

GMsotid (m)

4.66

5,20

5,41

5,01

3.99

5,33

3,13

5,08

GM' (m)

3,63

4,39

4,74

4,41

2,48

3,39

1,51

3,97

H I ' II ,

2.4.3 Results

The wind heeling moments, as calculated according to MODU code and DNV Rules,,

are translated into wind pressures for the contour as defined in PIAS.

Wind pressures for PIAS

215 Results of Intact stability calculations

All loading conditions comply with the stability criteria as stated in §2.2. A summary

of the stability calculations can be found in appendix 2.

25.1 Extra pay-toad on fret de ck area

An extra loading case is defined to determine the maximum allowable weight of extra

payload on the free deck area. A drilling condition with 70% consumables is chosen

for this purpose. The payload on the free deck area can be 4000t (1000t for all other

[loading conditions). The trim is -0,9 m. and all stability requirements are satisfied.

The results can be found in appendix 2.

TYPE I

11

FREE DECKER

Moment (1cNm)

'

Displacement (t)

I

Lever (m)

1 V = 36 mis

88.708

43.410

0,208

V = 51,5 m/s

181.539

43.410

I

0,426

V = 25,8 m/s

45.561

43.410

I

0,107

Pressure (kg/m2)

Elevation (m)

I

V= 36 m/S

I

V = 51,5 m/s

V = 25,8 rn/s

0 - 15

,

80

I

-

164

42

I

15-30.

1

94

192

48

30-45

105

215

1

53,75

I

45-60

1

90

I

1841

46

60 - 75

1

70

,

143

I

35,5

75 - 90

70

ii

143

1

35,5

90- 105

I

70

I

1431

35,5

II

Attained value per loading condition

Crit

Req.

1

2

3

4

5

6

7

'8 1

25

35,66

32,10

36,83

35,08

34,47

35,47

32,928

33,303

2

0,200

2,45

2,303

2,830

2,610

1,823

2,340

1,384

2,252

3

0,055

0,579

0,644

0,728

0,669

0,418

0,548

0,296

0,599

4

0,090

1,023

1,036

1,277

1,135

0,740

0,970

0,523

0,988

5

0,030

0,443

0,391

0,549

0,466

0,322

0,422

0,226

0,389

6

0,150

3,626

4,388

4,743

4,412

2,476

3,389

1,508

3,966

7

1,4

7,26

5,19

9,13

6,37

6,50

6,82

3,91

2,64

8

30

65

59

72

64

59

64

51

59

9

30

64

58

71

64

58

63

50

571

3 Damage stability

3.1 Requirements

Regarding the fact that the vessel is subdivided in many small compartments, no

difficulties are expected in meeting the damage stability criteria. Nevertheless, the

most critical damage cases will be examined.

IMO MODU Code regulations are to be satisfied for all loading conditions, MARPOL

regulations only apply to conditions with oil in cargo tanks (conditions 5,6 and 7)

IMO MODU Code

Requirements:

The metacentric height in the flooded position is positive.

The area under the righting moment curve shall be at least equal to the area under

the wind moment curve up to the second intercept of the curves.

The extent of damage to be applied is the flooding of any one compartment.

The wind moment curve should be based on a wind velocity of 25,8 m/s.

MARPOL

Requirements:

In flooded condition the angle of inclination <300

In flooded condition the righting lever has at least a range of 20° beyond the

position of equilibrium in association with a maximum residual lever of at least

0,1 m within the 20' range.

The area under the curve within this range shall not be less than 0,0175 mrad.

Longitudinal extent of damage:

11,09m

Transverse extent of damage:

7,00 m

Vertical extent from baseline upward without limit.

The wind moment curve should be based on a wind velocity of 25,8 m/s.

TYPE I

12

3.2 Results

For the requirements as stated in §3.1 , the maximum allowable VCG' is calculated at

several drafts. The outcomes are represented in figure 3.1. The maximum allowable

VCG' for the individual damage cases can be found in appendix 3.

Maximum allowable VCG'

Figure 3.1.

Maximum allowable VCG'

The characteristics of the loading conditions that were used for the intact stability

calculations are plotted in this graph. It becomes clear that all requirements are

satisfied. As a reminder, a summary of loading conditions is given underneath.

Condition

1

Sailing 90% consumables

2

Sailing 10% consumables

3

Drilling, BOP connected, 90% consumables

4

Drilling, BOP connected, 10% consumables

5

Testing 90% consumables, 98% crude storage

6

Testing 50% consumables, 50% crude storage

7

Testing 10% consumables, 98% crude storage

8

Survival condition, 10% consumables

^

0

24

22

20

18 16 14 12 10

8

#2

4

IMO MODU Code

7

1 3

6

MAR POL

TYPE I

13

FREE DECKER

4

5 6 7

8

9

10 11 12

Intact draft (tn)

4 Resistance and propu I sion

4.1 General

The propulsion consists of two azimuthing thrusters above keel level at the stern. For

the sailing condition a transit speed of 12,5 knots is considered. This transit speed is

regarded as a trial speed.

4.2 Resistance

The resistance is calculated according to Holtrop and Mennen

"A statistical Re-analysis of Resistance and Propulsion on

Data". The results can be found in appendix 4. Ordinary

moonpool designs have a great impact on the overall resistance.

Model tests at MARIN showed that alternative moonpool

designs could reduce the added resistance due to the moonpool

by as much as 25%. For this vessel an alternative moonpool is

selected with a wedge on the upstream side and a cut-out on the

downstream side of it. According to MARIN model tests on

ships with similar thruster and moonpool configurations, a

resistance increase of 52% of the bare hull resistance is

estimated (12% due to the moonpool and 40% due to thruster

headboxes).

4.3 Thrusters for main propulsion and DP

For the two main propulsion/DP thrusters at the aft LIPS fixed pitch thrusters type

FS3500 are selected.

Technical data:

MCR 5000 kW at 600rpm

Prop. diam. 3500mm in nozzle

w= 0,15

Design speed 7 knots

Thrust at bollard pull 7901N

TYPE I

14

FREE DECKER

Ordinary moonpool

4.4 Results

For five drafts the resistance is calculated and the main propulsion azimuthing

thrusters are selected. In the following figure the relation between required and

delivered thrust is shown. In trial condition the draught will be approximately 9m

(loading condition: sailing, 90% consumables). The output of the resistance

calculation can be found in appendix 4.

1400

11200

alefll

11111erreriam

triii111111111

8

'9

'10'

11

12

13,

14

15

.V(kn),

t=6m

t=7m

t=8m

--x t=9m

t=l0m

2x5MW thrust.'

_

TYPE I

₁₅

FREE DECKER.

3

ce.

600

400

200

5 DP Station keeping

5.1 DP-requirements

For the assignment of DYNPOS-AUTRO notation, the following general

requirements are to be complied with:

An automatic positioning system with redundancy in technical design and physical

arrangement. This is to compensate for incidents of fire and flooding in addition to

technical failures.

This leads to:

Installation of an independently operating automatic and manual control system

Redundancy of position reference systems and sensors

Redundancy of thrusters and power generating- and distribution systems

5.2 Thruster system

The vessel will be equipped with the following thruster layout:

T3

T4

T5

T6

This system will secure maintenance of position and allows the vessel to keep its

heading in a range of plus or minus 400 around the optimum heading, at the worst

scenario.

The power generation system consists of two separate engine rooms. Each engine

room delivers 17,7 MW at 85% MCR.

TYPE I

16

FREE DECKER

Power

(kW)

Thrust

(kN)

2 azimuthing thrusters for DP and main propulsion (1 & 2)

5000

790

4 retractable azimuthing thrusters below keelplanc (3, 4, 5, 6)

3400

610

5.3 Environmental forces

The environmental forces acting on the vessel during DP operations consist of:

Wave drift forces

Current forces

Wind forces

Riser forces

5.3.1 Wave drift forces

The wave drift forces are calculated using Gusto's computer program

FACET-DRIFT, a wave drift program based on a pressure integration technique. The panel

model of the vessel is presented in figure 5.1.

Figure 5.1.

Panel model for calculation of drift & current forces

TYPE I

17

5.3.2 Current forces

The current forces acting on the vessel are calculated using Gusto's computer

program CURRENT. This program determines the flat plate friction resistance and

the pressure resistance of an arbitrary hull-shape. The program was validated against

model-test experiments with large tankers.

The same panel model was used as for the calculation of drift forces (see figure 5.1).

Figure 5.2.

Results for a current of II m/s

Current forces Fy (kN)

II0

Fy max 827 kN

TYPE I

18

FREE DECKER

urren I Iorc ikN),

5:3.3 Wind forces

The computer program WINDOS is used to determine the wind forces on the vessel.

The computational model is based on a so-called building block approach. This means

that a structure is thought to be built up by standard components with known force

characteristics. The model' is represented in figure 5.3, the results are presented in

figure 5.4.

114

Figure 5.3.

Block model for WINDOS.

240 20 a31/111110"Nalligitet ° 40 30 00

Age&

80 00 10

ipitatap"i

/0

I I

gri

e°!1' fittin

an,80 280

_am

rouno4.7-:1111.11

270 280

sonitH,

0

des,

est

'4111

°

a

w vlamait

230

S

Salle

140 220 210

malls

180 so 170 180 xixurore4s(KN)

Figure 5.3.

Results, for a wind speed of I mis

00

I Fx

Fy

'TYPE I

FREE DECKER

19

5.3.4 Riser force

The riser forces are calculated according to the following formula:

The current profile is derived from Gulf of Mexico data.

For the capability calculations of the intact thruster system, a high current of 1,1 m/s

is applied, resulting in a riser force of 170 kN.

For a DYNPOS-AUTRO failure, a low current of 0,75 m/s is applied, resulting in a

riser force of 80 kN.

5.4 Thruster forces and consumed power

5.4.1 General

For several environmental conditions DP power plots are prepared. Furthermore, the

thruster use of all thrusters at each heading is calculated for these conditions. For both

intact and damaged condition (DYNPOS AUTRO) a capability plot is prepared. This

data can be found in appendix 5.

5.4.2 Environmental conditions

DP calculations are performed for several environmental design conditions.

'Condition

and 2

Max. drilling

Condition 3 and 4

Stand - by

Condition 5 and 6

DYNPOS AUTR

Condition 7 and 8

DYNPOS AUTRO

* 2

V current * Cd * L* D

condition

Hs

(m)

Tp

(s)

Wave din

(deg)

(m/s)

Wind dir.

(deg)

Vcurrcnt

(m/s)

Cur. dir.

(deg)

1

6,0

11,5

180

25

180

1,1

180

2

6,0

11,5

180

25

90

1,1

180

3

10,0

16,5

180

30

180

1,1

180

4

10,0

16.5

180

30

90

1,1

180

5

6,0

11,5

180

25

180

1,1

180

6

6,0

11,5

180

25

90

1,1

180

7

5,8

10,3

180

20.6

180

0,75

180

8

5,8

10,3

180

20,6

90

0,75

180

TYPE I

20

FREE DECKER

Friser

*

seawater ' r

5.4.3 Intact thruster system

For the intact system the following results are found:

5.4.4 DYNPOS AUTR failure

For DYNPOS AUTR operations, regulations are such that during any single failure,

the total system shall not lead to critical situations caused by loss of position or

heading. The most onerous situation is the lost of one of the stern thrusters. The

results are then:

5.4.5 DYNPOS AUTRO failure

In case of a DYNPOS AUTRO failure, one engine room or one main switchboard

room is out of order. The DP arrangement is such that in this case either thruster 1 and

5 or thruster 2 and 4 are out of order. The calculated power consumption is then:

Environmental

condition

Required power (MW)

Available thruster

Heading 180° off stern

Heading 1500 off stern

1

7,2

12,6

23,6

2

10,8

9,3

23,6

3

9,1

15,8

23,6

4

15,2

14,1

23,6

Environmental

condition

Required power (MW)

Available thruster

power (MW)

Heading 180° off stern

Heading 150° off stern

5

7,0

12,3

18,6

6

10,6

9,1

18,6

Environmental

condition

Required power (MEW)

Available thruster

power (MW)

Heading Bo° off stern

Heading 150° off stern

7

5,1

9,5

15,2

7,3

5,9

15,2

TYPE I

21

FREE DECKER

power

I

8

5.4.6 Total power balance

For drilling operations a power balance is made. Consumed power for drilling and

hotel is estimated at 7 MW. For the most onerous situations the power balance is

made up.

Intact (envir. 3 & 4)

The amount of available power (35,4 MW) is sufficient in intact condition.

DYNPOS AUTRO (one engine moth down, envir. 7 & 8)

The amount of available power (17,7 MW) is sufficient to satisfy DYNPOS AUTRO

.

regulations.

Power consumption (MW)

J

Heading 1800 off stern

Heading 150° off stern

DP

15,2

15,8

I Drilling ,& hotel

7,0

7,0

Power consumption (MW)

Heading 180° off stem

Heading 150'" off stem

LIT

7,3

9,5

fl Drilling & hotel'

7,0

7,0

TOTAL

22,2

22,8

TYPE I

22

FREE DECKER

6 Power generation an d distribution system

6.1 Power generation

The power generation will be diesel electric. Two separate engine rooms are situated

near the stern of the vessel. This secures that no exhaust gas will run over the drilling

area or heli-deck thereby improving workability. Each engine room contains four

Wartsila 12V32 engines and alternators. The total power supply is 41,7 MW at MCR.

Technical data Wartsila 12V32

Engine output

5400 kW (MCR)

Alternator output

5210 kW (MCR)

# revolutions

720

rpm

Fuel consumption

180

g/kWh

6.2 Power distribution system

The power distribution system is presented in the key one-line diagram on the next

page.

The power from the alternators is directed to two main switchboards. Each

switchboard is connected to three thrusters. Redundancy is built in by application of

tie lines, circuit breakers and change-over switches at two thrusters. Primary power

for main consumers will be generated and distributed at 6,6 kV, 3phase, 60 Hz.

Secondary power for auxiliary consumers and emergency power will be distributed at

440 V, 3phase, 60 Hz. Lighting and small power will be 230 V, single phase, 60 Hz.

Main drilling equipment will be fed by 600V DC.

TYPE I

FREE DECKER

Mail! switchboard 1 6..6 kV - 60 7 3 engrie room 1 _11

IJ

Thruster 1 Thruster auxiliary switchboard 1 440V L.

-230 V lighting Thruster 5

8 MAIN GENERATORS

6510 kVA

5210 kW

720 rpm

60 Hz

X

tie-line ie-line tie Aline

X

_

r

---1

r-I imain drilling equipment i

L

4

L SCR switchboard 1 600 V SCR Switchboard 3 shore connection 230 V emergency lightifig

KEY ONE-LIN

emergency generator /200 kW

Thruster 2 emergency _switchboard 440 V

-TiOtirtitTgli

r

n

ii 1 i dean supPty 1

i

switchboard

L

440 V for navigation equipment an

radio station 440 V at/salary itthboard 2 440 V eir-giise room 2 Main switchboard 2 6.4 kV - 60 Hz wire-

9 Ti

19 12

KEYPLAN

e

T5

T6 9

SYMBOLS

Diesel engine Frequency converter AC Generator AC Motor _{Change-ovef switch Circuit breaker}

0

₇₄

0

0

I

X

E DIAGRA V

Thruster 4 Thruster 6 a

j

T3 3 -J

-

-6.3 Load balance

For five conditions the electrical loading by thrusters, drilling equipment, hotel

facilities and auxiliary equipment is presented in an electrical load balance.

The five conditions are:

Harbour

Sailing

Drilling moderate weather (thruster loading I5%)

Drilling rough weather (Hs = 6m, V. = 25 m/s, vc = 1,1 mis, heading 20°)

DNV DYNPOS AUTRO (Hs = 5,8m, V, = 20,59 m/s, Vs = 0,75 m/s, heading 30r,

(one engine room and two thrusters out of order)

The results of the DP-calculation have been used for the loading from the thrusters..

The total load balance can be found in appendix 6, the results and the loading on the

generator sets are presented in table 6.1.

Table 6.1.

Load balance and loading on generators

TYPE I

24

FREE DECKER

harbour

sailing

drilling

moderate

weather

drilltnnough

weather

(condl)

Mt NPOS

[

AUTRO

.,

(cond7)

I I trusters

I 0 ;

9474

3125

10899

9913

Ship's auxiliaries

1265 1490

2819

3410

3410

SCR Drilling system

1 0 ; ;

0

4967

4967

4967

Drilling auxiliaries

0 ' ;

76

1930

2006

2006

I

total required (kW)

I ₁₂₆₅₁ 130401 113443

24283

20356

rated

power

power

power

I power;

power'

power at

l(MCR)

(MCR)

(MCR)

(MCR)

(MCR)

power supply

MCR

on/off (kW)

on/off (kW)

on/off (kW)

on/off ' (kW)

on/off (kW)

Engine row il

gen.set 1

5210

; 4 i '

5210

, I;

5210

7

1

5210

1 I ,

5210

0

-out

gen.set 2

5210

ii

a

0 0 o 1

5210

1

5210

Clout

out

gen.set 3

5210

0 0 0 0 ' Or 0 0 1

o

o

out

gen.set 4

;

5210

0

0

0 o I (1 o 0 1

0

0:

out

Engine room

F I i I

gen.set 5

5210

0 0 1

5210

: 1

5210 L/

1 I

5210

1

gen.set 6

5210

0

0

I' 5210 1I

0

0 1 1

5210

1

5210

gen.set 7

5210

0 0 0 0 I (li 0 1

5210

1

5210

gen.set 8

5210

0 0 0 0 0 IF 0 0 0 1

5210

emergency / harbour generator

I AO 0 0

Inn

0

0 0

I

Loading on generators

0.24

0.71

1

0.86

0.82 I

I

0.98

2

5210

0 0

7 Down time

if Motions

For a typical loading condition (drilling) with a draught of 8,5 m the motion

behaviour and the down time are determined. The program "Seaway" is used to

determine the motion characteristics. The "Seaway output and RAO's can be found in

appendix 7a. For the downtime calculation the motion behaviour in several specific

seastates is needed. The Jonswap wave spectrum for eleven zero crossing periods with

peak enhancement factor 2 and a significant wave height of lm. is used. Since

Seaway output is in significant values, all values are transformed into maximum

amplitudes by multiplication of 1,86. In the following figures the motion behaviour is

presented. The unit on the y-axis is m/m for heave and deg/m for roll and pitch.

Heading 180 deg

s heave

pitch

7.2 Downtime

The motion behaviour in those eleven seastates is suitable for implementation in the

program "Downtime". This program linearises the relation between wave height and

motion behaviour by multiplying the wave height from the wave scatter diagram with

the Seaway output for Hs = lm. If this value is larger than the criteria downtime

increases. Downtime is calculated for three headings (150°,165°and 180°)and for

three sets of criteria. The wave scatter diagram of the Golf of Mexico (area 15) is

used.

The following criteria are used (maximum amplitudes):

1.40 1.20 1.00 0.80 0.80 0.40 0.20 0.00 Heading 150 deg 5 10 15 20 25 30 35 T. Cs) heave roll pitch 1.40 1.20 1.00 0.60 0.60 0.40 0.20 0.00 0 Heading 165 deg 5 10 15 20 25 30 35 T. CO

criteria

Heave

Roll

Pitch

Running casing (I)

1,5 m

1.5°

1.5°

Drilling (2)

3,0 m

2,5 °

2,5 0

Tripping (3)

3,75 rh,

350

3,50

TYPE I

25

FREE DECKER

1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 0 5 10 15 20 25 30 35 T. (s1 heave 01101 ,

The results of "Downtime" are tabelised below. Downtime plots are in appendix 7b.

A heading distribution of 40%180% 40%-165° and 20%-150° is used.

The output of "Downtime" is the chance of exceeding the criteria, based on a three

hours interval. This output is transformed in an annual downtime rate. The yearly

downtime is estimated by simulating a typical drilling program. This method is

described in report 6204.1000.301 ,chapter 7.5.1. page 102-103. The annual downtime

calculation is presented in table 7.1.

Table 7.1.

Annual downtime

The annual down time in this estimation is 18,8 days.

TYPE I

FREE DECKER

\PA-(PP

6L9/4-26

Heading

Casing

Drilling

Tripping

180°

3,37%

0,26%

0,11%

1650

3,37%

0,26%

0,07%

150°

4,60%

1,12%

0,22%

critiria # 3 hours int.

downtime

hours

drill eval. pilot

7

₁₆

7%

3.15

reenter and open

2

16

7%

3.15

run & cement

1

8

25%

6.11

open pilot

9

₂₄

10%

6.90

run & cement

1

20

17%

10.08

run riser

1

20

17%

10.08

land BOP

1

8

25%

6.11

BOP test

2

8

3%

0.81

tripping

3

36

1%

0.75

drill

2

48

1%

1.24

log & open

2

62

6%

11.84

run & cement

1

16

14%

6.57

test stack

9

8

3%

0.81

tripping

3

150

1%

3.12

drill

9

₂₀₀

1%

5.18

log

1

40

4%

4.34

run

1

74

20%

14.25

test BOP

2

8

3%

0.81

tripping

3

72

1%

1.50

drill

9

₉₆

1%

2.49

log

1

40

17% 20.16

disconnect

2

3

1%

0.12

pull riser

1

13

36%

14.02

plug and abandon

2

24

10%

6.90

total

2880

4.88% 140.49

8 Hull strength

The longitudinal strength is calculated according to DNV regulations. A midship

section is designed following the rules with respect to local and global strength..

8.1 Loadings'

The stillwater bending moments and shear forces are calculated for all typical loading

conditions,, as defined in chapter 2. The maximum bending moments and shear forces

occur at condition "Testing 98% crude, 90% consumables". The calculated values

_are

compared with the design stillwater bending moments and shear forces

_{as stated in the}

rules. A plot can be found on one of the following pages. The shaded area on the plot

represents the deck opening in the moonpool area, with longitudinal extension. For

the bending moment the design value is applied, for shear force the calculated

_value.

8.2 Midship section

The most awkward Ideation is around the moonpool area. Figure 8.1 displays the

cross section in this area. The black members are considered effective; the red

members do not contribute to the longitudinal strength.

Figure 8.1.

Cross section

The dimensions of stiffeners are dictated by local strength requirements. Plate

thickness is dictated by global strength requirements. For details of the

_calculation,

reference is made to appendix 8. A drawing of the

_{cross section can be found on. one}

of the following pages.

TYPE I

₂₇

FREE DECKER

.

±1

1 . , i

IMMO

III

OF

Structural loading co

parison between

D\V rules and loadings as caLculated.

31540 kN

'D NV

from loading conditions

A

Absolute shear force curves

FREE DECKER

121114 IkNm

Bending moment curves

from loading conditions

105674 3 kNm

41468kN

21 16 16 14 3500 1 I 3600

I4000

14

1

1 1 1 1 1 1 1

Bas

6400

C CO

d

s

p

sect

HP 260)(11 HP 200x11 _{HP 24000}

on

pLa

HP 220x10 W L 11 m 4 1 HP 180x11

NN..,

HP 260x11

Requirements

Attained values

Material

All transverse plating arid stiffeners in

midship area NV-N5. yield stress 235 N/rnm2 All longitudinal plating and stiffeners midship area NV-32, yield stress 315 Nimml

HP 180x10

Principal dimensions

Rule length

192.0 in HP 180x10 Breadth 35.0 m r- i I I 1 HP 180x10 HP 180x10

Depth Draught far rules scantlings

11,0 in

Neutral axis from keelplane

8,17

Section modulus at main deck

14,58 mi

Section modulus at bottom

17,55 ml

Moment of inertia about the neutral axis

14336 rn`

Midship section mudulus about the neutral axis

14,56 46

Midship moment of inertia about the neutral axis

107,33 m`

Combined thickness lbhd 6 side plating for shear

17.29 mm

CLASS

DE

NORSKE VERITAS

ship section

25 21 3 t HP 14

8.3 Results

Due to the lack of effective material in the upper region of the cross section, the

section modulus at main deck is a critical requirement. In order to minimise the hull

steel weight, the neutral axis is raised as much as possible, to 8,17 m from keelplane.

Results from strength calculation:

8.3.1 Material

All longitudinal plating and stiffeners in the midship area will be high strength steel,

NV 32, yield stress 315 N/mm2.

All transverse plating and stiffeners, as well as all material outside the midship area,

will be mild steel, NV NS, yield stress 235 N/ mm2.

In this context, the midship area runs from the fore engine room bulkhead to the aft

accommodation bulkhead. In the weight calculation, this area is referred to as section

2

5.

TYPE I

FREE DECKER

Required

Attained

Section modulus about neutral axis

Z

14,56 m3

Zdeck

14,58 m '

Zbottom

17,55 m'

Maximum stress

I

-107,33 rn4

deck

224 Mite

bottom I

186 N/mm2

143,36 m4

Moment of inertia about neutral axis

Combined thickness lbhd & side plating

for shear requirements

t

17,29 mm

t

30,0 mm

9 Hull weight

Based on the midship cross section as derived from the strength calculation the basic

hull weight is calculated. The ship is longitudinally subdivided in six sections with a

more or less similar cross section. The objective is to get a cross sectional area and

multiply this with the length of the section. The area of the midship section as

calculated in the strength calculation is directly used in this weight calculation with a

reduction for the fore and aft ship. For each section, steel in decks and longitudinal

stiffeners, which is not accounted for in the strength calculation, is added to the cross

sectional area of that section. Transverse stiffeners (bulkheads, webframes and floors)

are added to the longitudinal members and the total volume of steel can be calculated

with an additional 5% for brackets. In figure 9.1 the sectional subdivision is

presented, the outcome is presented in table 9.1.

The total hull steel weight is 9105 ton of which 41% is made of high strength steel.

This hull steel weight very much resembles the method of Johnson. Hagen and

Ovrebo used in the preliminary weight calculation (9139 ton)

Table 9.1.

Hull weight calculation

TYPE I

29

FREE DECKER

sectionI section 2 section spoon4 section) sectionto

A (cm2) A (cm') A (cm) A (cm') A (on') A (cm')

strength 30730 strength 30730 strength 30730 strength 30730 strength 30730 strength 30730

deck 3200 deck 3200 moonpool 4186 deck 3200 deck 3200 deck 3200

bottom 2048 bottom 2048cofferdam 5760 bottom 2048 bottom 2048 bottom 2048

tanktop 1792 tanktop 1792 Woking 1792 tanklop 1792 innktop 1792

center girder 420 center girder 420 center girder 420 center girder 420 center girder 420

deck 1 448(1 deck 1 4480 deck I 4480 deck 1 4.180

deck2 4480 deck2 4480 deck2 4000

reduction -11788 deck) 3500

reduction -10034

10111 3'1,363 Islet .1 I 511 10 al I I 101d1 426 /0 total 40190 total 40136

volume

section A Length As L weight LCG moment

(cm') (nil

(d)

(ton) (m) Mono,

1 35362.77 49 60 7540 1377 18.4 25335 2 47150.36 3360 110.43 1244 60 74618 3 40676.36 12.80 52.07 409 83 2 34005 4 42670.36 II 20 47.79 375 95.2 35715 5 3819036 9200. 198.59 1559 126.8 197672 6 40136.29 45 40 8222 1430 1764 252326 transverse #(.) weigth/t/ Main bulkheads 7 89.02 623 96 591)21 Small bulkheads 7 49.46 346 96 33234 Webframes 75 5.09 382 96 36625 Floors 75 12 36 927 96 89019

lotto "/0 41 0611 030 VOA( hull steelweight tend 9105 Ion

Lungilmlion1 Fiteel 7.85 kg/to

5

I

I

arelion

111

17001-Mil

raIrAILT

S

m IIIIMME

lallOWIMMOITI

metomn

1111111111r1WITI

newmpaint

I

mmmmm u

1,11

Er

teas, OMNI

Figure 9.1.

Sectional subdivision

TYPE I

30

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I 1

10t Building price

For the estimation of the building price, the ship is subdivided in groups (same as

those used in the weight calculation), a sample of such a group is shown in table 10.1.

Two large posts are steel and drilling equipment. The primary steel costs are

estimated to be 2,5 $/kg for mild- as well as for high strength steel (included

manufacturing), since the price difference for mild and high strength steel is very

small, hfl 0,79 for mild steel and hfl 0,90 for high strength steel. The price of

secondary steel is estimated to be 8 $/kg. The group steel weight is presented in table

1101 The other large post is drilling equipment. Total drilling related equipment is

estimated to cost 75 mln $.

For the other posts a price per kg is estimated or manufacturers are consulted for exact

prices. In table 10.2 the weight and price of the weight groups is summarised. The

total building costs are estimated to be 184.2 mm n $.

Steel weight

tectmdsev stee

Table 10.1.

Steel weight group

Input sir W vcg (m) leg (m) coseilt costs -fl primarysteel hull

skeg 910, 50 2.0 96. e 8.0 2.3 3.5 22,764 175

-

-1 'funnels I 50 24.0 18.0 3.5 175 1 substructure & drillfloori 700 24.0 83.5 3.5 2,450

rtitte pedestral 3 51 18,0 100.0 19100 573

nforcements thrusters 4 80 30:0 120.0 8,0 '640

hale shaker house

r

11 5 21.0 56.0 8.0 920 engine foundation II 200 10.0 19,0 8.0 1.600 mingency ' 259 110.0 95.0 8.0 2,070 Input or Vi (t)

In

(us)' leg (en) costsit costs'

tan room 20 21u.0 165.0 160

loose foundations.. 150i 10:0 95.0 1 8.0 1,200

bulwarks 25 8.0 95.0

to

200 hatches 1 35 18:0 95.0 1 1.0 280 loose tanks 25 115.0 95.0 8.0 200 metal floors 701 9,0 95.0 560 platforms 30 13.0 95.0 8.0 240

nickels including rails I 20 C.4.0 95.0 8.0 160

1 manholes coven i 10 4.01 95.0 8.0 80 output weight 110610 veg 11.00 cg 93.3 coos 31,367 output weight, 385 yogi 11.60 leg 98,6 'costs 3,080

TYPE I

3

FREE DECKER

(t) 9.7 8.0 8.0

Table 10.2

Light weight and building price calculation

Lightship weight calculation

- Costs ($)x1.000 31,367 3,080

}

75,000 8,400 18,256 15,000 5,100 4,500 18,280 3,750 1,500

184,233

group steel weight 1 2

Drilling

3 4 5 6 7 8 9 Systems 10 11 12 13 14 15 Personel 16 17 18 19 Steel

weight

(t)

10,610 385 760 423 1,220 71 183 72 95 830 490 315 1,870 300 283 1,305 820 460 245

20,737 t

portion

51.16%significant 1.86%significant 3.66%significant 2.04%significant 5.88%significant 0.34%not significant 0.88%not significant 0.35%not significant 0.46%not significant 4.00%significant 2.36%significant 1.52%significant 9.02%significant 1.45%significant 1.36%significant 6.29%significant 3.95%significant 2.22%significant 1.18%significant

VC('

t.y

(in)

(m)

11.00

93.26 11.60 98.64 56.83 83.50 10.76 68.85 22.30 89.84 29.37 141.00 30.51 104.55 21.00 65.00 26.00 83.50 11.70 19.00 11.34 81.12 14.59 68.86 9.11 96.36 24.00 14.00 12.08 20.62 27.66 166.92 24.00 115.00 37.13 103.21 23.57 169.39

16.10

93.55 secundary steel equipment

Major rig equipment

Mud system Subsea equipment Marine riser system Pipe handling

well test&

logging

Substructure piping Diesel engines

Mooring

&SK systems

Electrical system

Auxiliary systems

Topsides Crude handling Accommodation

Quarters&shop furn.

Material handling

Lifesaving

&rescue

total

TYPE I

32

FREE DECKER

Appendices

Appendix 1

General arrangement

Thruster retrieving system

Appendix 2

Wind heeling moments calculation

Hydrostatic particulars

Tank arrangement

Intact stability calculations

Appendix 3

Damage stability

Appendix 4

Resistance calculation

Appendix 5

Capability / feasibility plots

Appendix 6

Load balance

Appendix 7a

Seaway output

RAO plots

Appendix 7b

Down time plots

Appendix 8

Appendix 1

General arrangement

Thruster retrieving system

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