Post on 12-Apr-2017
Offshore Support Vessels Design
By: Ahmed Taha Abd El-Mawla
Contents
• Introduction• Design of the vessel • Resistance of the vessel • Construction of the vessel • Weight of the vessel• Intact Stability
Introduction
• The origin of offshore support vessels may be traced to the Gulf of Mexico. where oil exploration first moved offshore in the 1950s.
• Surplus World War II vessels and wooden fishing boats were used to supply offshore rigs
Design and operating capabilities
• Large and open aft deck.• Highly maneuverable, particularly at low speed.• Storage for offshore exploration and production activities:
such as bulk mud and cement, potable water• Wheel house all - round visibility (have forward & aft control) • High engine power for towing operations. • Some OSVs are equipped with big fire pump with monitors for external
firefighting system. • Dynamic Positioning (DP) system is very important for all types of OSVs.
Types of Offshore Support Vessel
• Anchor Handling Towing Supply vessels (AHTS) • Diving Support Vessels (DSV)• Platform Supply Vessels (PSV)• Cable & Pipe Laying Vessels• Standby and Rescue Vessels• Multi-Purpose Service Vessel (MPSV)
Features of offshore supply vessel
Work deck
Anchor roller
Steering gear
Ducted propellerStern TubeTransverse Thruster
Tanks For dry bulk
Deck cranes
Propeller shaftGear boxMaine engine
Life raft
MOB-boat with crane
Storage reel for steel wires for anchor
BridgeFirefighting monitor
Switchboard
Design of vessel • The design of a ship is an iterative process, in which early estimates
are made.• Then repeatedly corrected.• Design and Construction – IMO A.469 (XII)
• Design spiral• Main Particulars
Length overall = 20 mLength B.P. = 19.3 mBreath moulded = 6.66 mDepth moulded = 3.3 mDesign draught = 2 m
Design of vessel • Lines Plans
Before After
• Generation of the hull surface
Design of vessel
• General Arrangements
Design of vessel
Outboard Profile
Below Main Deck
• Preliminary hydrostatic calculations
Displacement 122.9 tVolume (displaced) 119.895 m^3Draft Amidships 2 mImmersed depth 2.015 mWL Length 19.392 mBeam max extents on WL 6.144 mWetted Area 136.187 m^2Max sect. area 7.821 m^2Waterpl. Area 105.717 m^2Prismatic coeff. (Cp) 0.79 Block coeff. (Cb) 0.499 Max Sect. area coeff. (Cm) 0.636 Waterpl. area coeff. (Cwp) 0.887
LCB length -0.158 (+ve fwd) mLCF length -0.504 (+ve fwd) m
LCB % -0.813 (+ve fwd) % Lwl
LCF % -2.599 (+ve fwd) % Lwl
KB 1.333 mBMt 2.41 mBML 23.723 mGMt corrected 3.743 mGML 25.056 mKMt 3.743 mKML 25.056 mImmersion (TPc) 1.084 tonne/cmMTc 1.588 tonne.m
Design of vessel
Resistance of the vessel
0 2 4 6 8 10 12 14 16 18 20 22 240
50
100
150
200
250
300
Resistance Vs. Speed
Resistance
Speed Knots
Resis
tanc
e KN
33.2 KN
0 2 4 6 8 10 12 14 16 18 20 22 240
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
Speed Vs Power
Power
Speed Knots
Pow
er K
WResistance of the vessel =
280 KW
Construction of vessel
• Calculation in detail according to the ABS rules:Offshore Support Vessels 2016-Part 3 Hull Construction and Equipment
• CHAPTER 2: Hull Structures and Arrangements
Midship Section6 .667 m
0 .5 m 1 .65 m
L.75*50*6
T.150*130*123 .3 m
Deck 7 .5mm PL.
Side 7 .5 mm PL.
Bottom 8mm PL.
3D Model Representation
Weight of the vessel
Light weight Estimations
Steel weight 25 tonOutfitting Weight 3 tonMachinery Weight 5 tonTotal Light Weight 33 ton
Dead Weight
• Dead Weight = displacement – light weight
Freshwater 18.00 tonDry bulk cargo tanks (cement) 15.00 tonFuel oil 2.00 tonOil cargo 38.00 tonFreshwater cargo 15.00 tonWeight for persons 2.5 ton
Intact Stability• Loading Conditions1. Light weight Condition 2. Full load Condition 3. Vessel with 10% of consumables ,departure condition.4. Vessel with 10% of consumables ,arrival condition.
Equilibrium
Draft Amidships m 1.960Displacement t 118.3Heel deg 0.0Draft at FP m 2.012Draft at AP m 1.909Draft at LCF m 1.958Trim (+ve by stern) m -0.103WL Length m 19.399Beam max 6.123LCB. (+ve fwd) m -0.018LCF. (+ve fwd) m -0.479
Full load Condition KB m 1.309KG fluid m 1.749BMt m 2.447BML m 24.444GMt corrected m 2.006GML m 24.003KMt m 3.755KML m 25.752Immersion (TPc) tonne/cm 1.075MTc tonne.m 1.464Max deck inclination deg 0.3033Trim angle (+ve by stern) deg -0.3033
= 3.755-1.749 = 2.006
Light weight Condition 10% departure condition10% arrival condition Draft Amidships m 1.018Displacement t 33.00Heel deg 0.0Draft at FP m 0.657Draft at AP m 1.379Draft at LCF m 1.071Trim (+ve by stern) m 0.722KB m 0.769KG fluid m 1.839BMt m 3.481BML m 54.615GMt corrected m 2.410GML m 53.544KMt m 4.248KML m 55.346Trim angle (+ve by stern) deg
2.1329
Draft Amidships m 1.898Displacement t 112.6Heel deg 0.0Draft at FP m 1.775Draft at AP m 2.021Draft at LCF m 1.906Trim (+ve by stern) m 0.245KB m 1.279KG fluid m 2.005BMt m 2.500BML m 24.951GMt corrected m 1.775GML m 24.226KMt m 3.779KML m 26.228Trim angle (+ve by stern) deg
0.7251
Draft Amidships m 1.402Displacement t 62.82Heel deg 0.0Draft at FP m 1.311Draft at AP m 1.494Draft at LCF m 1.409Trim (+ve by stern) m 0.183KB m 0.973KG fluid m 1.927BMt m 3.064BML m 37.415GMt corrected m 2.110GML m 36.461KMt m 4.037KML m 38.387Trim angle (+ve by stern) deg
0.5406
Large Angle Stability
0 10 20 30 40 50 60 70 80 90 100 110 120
-0.5
0
0.5
1
1.5
2
Full Load GZ - θ CurveGZInitial GMMax GZ
Heel θ deg.
GZ m
Range of Stability
θ 𝒇
Initial GM
Max GZ
θ❑
CRITERIA REQUIRED
Area between 0 and angle of maximum GZ
3.1513
Area from 30 to 40 deg. 1.7189
Maximum GZ 0.200
Angle of maximum GZ 15
Initial GMt 0.150
full load Condition
23.7920
9.9358
1.005
38.2
2.006
light weight Condition
43.9612
11.2493
1.499
51.8
2.410
10% departure condition
32.4616
10.2960
1.161
46.4
2.110
10% arrival condition
18.6107
8.7455
0.882
35.5
1.775
IMO A.749 (18) ch4,5 Offshore supply vessels
20 40 60 80 100 120 1400
0.5
1
1.5
2
2.5
3
3.5
Cross Curves KN
0 deg KN m10 deg KN m20 deg KN m30 deg KN m40 deg KN m50 deg KN m60 deg KN m70 deg KN m
Displacement (ton)
KN m
KN Values Cross Curve of Stability
Upright Hydrostatics
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
20
40
60
80
100
120
140
0.0001 0.91823.887
9.267
17.5129.17
44.42
61.99
81.22
101.6
122.8
Draft Vs. Displacement
Displacement t
Draft (m)
Displacemen
t (ton)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
20
40
60
80
100
120
140
0.049.205
20.035
32.794
48.108
65.547
81.586
89.8297.129
101.504105.652
0.045
10.123
22.036
36.005
52.632
71.788
90.55
101.766
112.464121.427
130.268
Draft Vs. Area
Wetted AreaWaterpl. Area
Draft (m)
Area ( m^2)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
5
10
15
20
25
0.038 0.948 1.8952.842
3.7884.451 4.925
5.399 5.749 5.946 6.144
8.836
11.379
13.072
14.679
16.23317.779
18.922 19.053 19.173 19.28519.392
WL LengthBeam max
Draft (m)
(m)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.034
0.395
0.3730.355 0.343 0.356 0.384
0.417 0.4460.477
0.5
0.068
0.829
0.7650.722 0.694
0.681 0.6960.735 0.759 0.777 0.79
CpCbCwpCm
Draft (m)
(m)
Thank You