Static Stability Study of a Shallow Vee Hull Airboat for Sarawak

Riverine Application

Peter Yek Nai Yuh

Master of Engineering

(Mechanical Design & Computer Simulation)

2014

Static Stability Study of a Shallow Vee Hull Airboat for Sarawak Riverine

Application

Peter Yek Nai Yuh

This thesis is submitted in partial fulfillment of the

requirements for the Master of Engineering

Faculty of Engineering

UNIVERSITI MALAYSIA SARAWAK

JUN 2014

“I declare that I have read through this project report and to my opinion

this project report is sufficient in term of scope and quality for the purpose of

awarding the degree of Master of Engineering”

Signature: …………………………..

Name of Supervisor: ASSOC. PROF. DR HJ. MOHAMMAD OMAR ABDULLAH @

MAK KHOON LING

Signature: …………………………..

Name of Co-supervisor: ERVINA JUNAIDI

Title: Static Stability Study of Shallow Vee Hull Airboat For Sarawak Riverine Application

Date: JUN 2014

I declare that this project report entitled “Static Stability Study of a Shallow Vee Hull

Airboat for Sarawak Riverine Application ” is the result of my own work except as cited

in the references. The report has not been accepted for any degree and is not currently

submitted in candidature of any other degree.

Signature: …………………………..

Name of Candidate: Peter Yek Nai Yuh

Date: JUN 2014

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ACKNOWLEDGEMENTS

First at all, I would like to thank God for all the blessings and strength that He had

granted me upon completing this project. Secondly, I would like to express my appreciations

to my supervisors, Prof. Dr. Mohammad Omar Abdullah and Ms. Ervina Junaidi, for their

support, advice and help in the completion of this project. I also take this opportunity to thank

them for spending their time in helping me to prepare this thesis. I would like to express my

sincere gratitude to Prof. Dr. Sinin Hamdan and Mr. Peter Kuek for their kind assistance,

helpful advices and supports in the boat design and overall airboat study, respectively. I am

indebted to my family for providing me with the opportunity to further my study. Special

thanks to my parents, Mr. Yek Siu Tak and Mrs. Ting Heng Ing whom have always respected

and supported me in whatever decision that I made. Last but not least, I am deeply grateful to

all my fellow friends, especially Mr. Cyril Jourbert, Ms. Loo Yee Ling and Mr. Kong Wen

Keit for their helpful initial joint-study and priceless suggestion. Without them, it is

impossible for me to complete this study successfully.

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Abstract

This research aims to evaluate and explore the alternative of water transport varieties.

Sarawak with riverine condition has shown a high potential of airboat application and

development prospect as transportation is essential to bring people closer. This research acts

as a preliminary work that aims to take a fresh look on the Static stability of existing Shallow

Vee hull and follow with the PROLINES simulations for another two types of hull designs,

which are Flat Bottom and Modified hull. Centre gravity (KG), metacentric height (GM) and

metacentre above centre of buoyancy (BM) have shown the major influencing parameters

manipulating the static stability of airboat. Besides that, an airboat with Shallow Vee hull was

made for the stability performance testing in UNIMAS’s pool, and it has given an acceptable

range of testing results. Rpm of propeller, fuel consumption and wind speed have been

measured before hand. Subsequently airboat is operated to measure the average speed and

observed the overall stability during the turning. Naval architecture software, PROLINES is

used for simulation work of different displacement and type of hulls. Simulation results have

evaluated the airboat hydrostatics and statics stability performance. As a result, Flat Bottom

and Modified hull gives merits of static stability compared to Shallow Vee hull.

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Abstrak

Penyelidikan ini bertumpu pada penilaian dan meneroka untuk mempelbagaikan

pengangkutan air. Keadaan Sarawak yang penuh dengan sungai dan kawasan paya

menghulurkan penggunaan dan kemajuan “airboat” kerana pengangkutan teresebut

menghubung antara satu sama lain. Penyelidikan ini sebagai usaha asal untuk menilai

kestabilan melalui PROLINES terhadap hull yang berbentuk Vee cetek, rata, dan direka

semula. Pusat graviti, ketinggian metacentric dan jarak metacentre dari titik keapungan

merupakan tiga parameter yang memberi kesan yang utama kepada kestabilan keseluruhan.

Airboat dengan hull yang berbentuk vee cetek telah memberi keputusan yang memuaskan

semasa menjalani kajian pretasi stabiliti di kolam UNIMAS. Selain itu, pusingan kipas,

penggunaan petrol dan kelajuan angin yang dihasilkan oleh kipas telah diuji. Kelajuan dan

keseimbangaan keseluruhan juga dipertimbangkan semasa airboat membuat pusingan. Dengan

menggunakan perisian PROLINES, proses stimulasi telah dijalakan untuk menilai

keseimbangan kapal dengan berat yang berlainan. Di samping itu, keseimbangan hull yang

berlainan juga dinilai dari segi hidrostatik dan statik keseimbangan. Keputusan telah

menunjukkan kapal yang rata dan direka semula memberi keputusan simulasi yang

memuaskan dan lebih baik dibandingkan dengan bentuk yang Vee cetek.

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TABLE OF CONTENT

Page

DECLARATION

ACKNOWLEGMENT I

ABSTRACT II

ABSTRAK III

TABLE OF CONTENT IV

LIST OF TABLES VIII

LIST OF FIGURES IX

LIST OF ABBREVIATIONS XI

LIST OF SYMBOLS XII

CHAPTER ONE INTRODUCTION

1.1 Introduction 1

1.2 Sarawak Inland Waterway Transport 2

1.3 Essential of the Research 5

1.4 Objectives of the Research 6

1.5 Scope of the Research 7

1.6 Structure of the Thesis 8

CHAPTER TWO LITERATURE REVIEW

2.1 Review of Sarawak Riverine Condition 9

2.2 Review of Sarawak Inland Waterway Transport 10

2.3 Review of Airboat’s Application 12

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2.4 Review of Airboat’s Performance Research 15

2.5 Review of hull Stability Research 16

2.6 Evaluation of the Static Stability Performance 18

2.6.1 Calculation of Righting Arm (GZ) 18

2.6.2 Righting Arm Graph 22

2.7 PROLINES Simulation Review 24

CHAPTER THREE METHODOLOGY

3.1 Introduction 26

3.2 Flow Chart of Methodology 27

3.3 Parametric Measurement 28

3.3.1 Dimensional Parameter of Existing Shallow Vee hull 28

3.3.2 Inclining Test 30

3.4 PROLINES Simulation 33

3.4.1 Setting the Load Water Level (LWL) 35

3.4.2 Calculate the Hydrostatic and Stability Data 36

3.5 Initial Performance Testing 37

CHAPTER FOUR RESULTS AND ANALYSIS

4.1 Introduction 39

4.1.1 Overview of Constructed Airboat 40

4.2 Parameters Measurement and Calculations 42

4.3 Inclining Testing for Shallow Vee hull 42

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4.3.1 Initial Setting 42

4.3.2 Graph and GM Calculation 42

4.4 PROLINES Simulation 44

4.4.1 Hull Drawing 44

4.4.1.1 Drawing with Buttock, Waterline and Station lines 44

4.4.1.2 B-splines Drawing 46

4.4.1.3 Render Hull 48

4.4.2 Hydrostatic Simulation with Different Type of Hulls 49

4.4.3 Static Stability Simulation with Different Type of Hulls 56

4.4.3.1 Wave Drag 56

4.4.3.2 Friction Drag 57

4.4.3.3 Righting Arm Curve 58

4.4.3.4 Metacentre Radius (BM) Curve 60

4.4.3.5 Metacentre Height (GM) Curve 61

4.5 Overall Performance Testing 64

4.5.1 Rpm Measurement 64

4.5.2 Fuel Consumption Measurement 65

4.5.3 Wind Velocity Measurement 66

4.5.4 Airboat Speed Measurement 67

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CHAPTER FIVE CONCLUSION

5.1 Introduction 68

5.2 Conclusion 68

5.3 Recommendations for Further Works 70

REFERENCES 71

APPENDIX A Inclining experiment

APPENDIX B Hydrostatics data with different displacement simulation

APPENDIX C Stability simulation results of different types of hull

APPENDIX D Performance testing

APPENDIX E Related publication (Journal paper)

APPENDIX F Conference paper

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LIST OF TABLES

Table 3.1 Airboat part label 28

Table 3.2 Dimension of existing Shallow Vee hull 30

Table 4.1 General information and dimension of existing Shallow Vee hull 41

Table 4.2 The total weight calculation of the airboat 41

Table 4.3 (a) Initial setting for the inclining experiment 43

Table 4.3 (b) Calculation of the GM values from the inclining experiment 43

Table 4.4 Hydrostatic data of Flat Bottom hull 50

Table 4.5 Hydrostatic data of Shallow Vee hull 52

Table 4.6 Hydrostatic data of Modified hull 54

Table 4.7 Advantages and disadvantages of different hull design 63

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LIST OF FIGURES

Figure 1.1 Map indicating major navigable rivers in Sarawak 4

Figure 2.1 Metacentre above centre of buoyancy 18

Figure 2.2 Wall sided formula 20

Figure 2.3 Stability curve 22

Figure 3.1 Flowchart of research methodology 27

Figure 3.2 The airboat parts and ballasts 28

Figure 3.3 (a) The body view of existing Shallow Vee hull 29

Figure 3.3 (b) The profile view of the existing Shallow Vee hull 29

Figure 3.3 (c) The plan view of the existing Shallow Vee hull 29

Figure 3.4 Flow chart of PROLINES Simulation 33

Figure 3.5 (a) Edit with visual vertex editor 34

Figure 3.5 (b) Example of stability calculation dialog 34

Figure 3.6 (a) Tachometer used to check the rpm of propeller 37

Figure 3.6 (b) Fuel consumption measurements 37

Figure 3.6 (c) Wind velocity measured by using anemometer 37

Figure 3.6 (d) Real constructed airboat test run 37

Figure 4.1 (a) Overall drawing of constructed airboat by CATIA 40

Figure 4.1 (b) Back view of constructed airboat by CATIA 40

Figure 4.2 Results of the inclining experiment 43

Figure 4.3 (a) The Flat Bottom hull with stations, waterlines and buttock lines view 45

Figure 4.3 (b) The Shallow Vee hull with stations, waterlines and buttock lines view 45

Figure 4.3 (c) The Modified hull with stations, waterlines and buttock lines view 45

Figure 4.4 (a) The Flat Bottom hull with B-splines view 47

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Figure 4.4 (b) The Shallow Vee hull with B-splines View 47

Figure 4.4 (c) The Modified hull with B-splines view 47

Figure 4.5 (a) 3D Rendered Flat Bottom Hull 48

Figure 4.5 (b) 3D Rendered Shallow Vee hull 48

Figure 4.5 (c) 3D Rendered of Modified Hull 48

Figure 4.5 (d) 3D Bottom part of Modified Hull 48

Figure 4.5 (e) 3D Rendered of Body View of Modified hull 48

Figure 4.6 Hydrostatic curve of Flat Bottom hull 51

Figure 4.7 Hydrostatic curve of Shallow Vee hull 53

Figure 4.8 Hydrostatic curves of Modified hull 55

Figure 4.9 The wave drag Vs. velocity 56

Figure 4.10 The friction drag Vs. velocity 57

Figure 4.11 The value righting arm Vs. heeling angle 58

Figure 4.12 The value of longitudinal of BM versus heeling angles 60

Figure 4.13 The value of transverse of BM versus heeling angles 60

Figure 4.14 The value of longitudinal of GM versus heeling angles 61

Figure 4.15 The value of transverse of GM verses heeling angles 62

Figure 4.16 Fuel consumption vs rpm 65

Figure 4.17 Wind speed vs rpm 66

Figure 4.18 The airboat speed vs. Time 67

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LIST OF ABBREVIATIONS

MA Area of the immersed portion of the midships

WPA Area of the waterplane

Beam

B Breath of the submerge part

BM Metacentre above centre of buoyancy

CM Midship section coefficient

CB Block coefficient.

CWP Waterplane coefficient

D Depth

Fb Freeboard

GM Transverse metacentric height

KG Centre of gravity

KM Transverse metacentre above keel,

LOA Length overall

WLL Length on the waterline

LWL Length on waterline

Tf Draft forward

Draught of the submerge part

T Draught

Tp Static thrust of propeller

W Displacement

B

T

xii

LIST OF SYMBOLS

immersed volume m3

θ Deadrise / pitch angle °

specific gravity m/s2

Heeling angle °

static efficiency

angular speed of propeller rad·s−1

1

CHAPTER ONE

INTRODUCTION

1.1 Introduction

Sarawak is known as „The land of many rivers‟ (Staub et al, 2000). The rivers provide a

natural means of transportation and communication which connect the rural areas and the

urban areas that are not accessible through the land transport. Many rivers in Sarawak are

lined with longhouses and rainforest, making a safari down these rivers a unique experience,

especially for visitors and tourists from urban or metropolitan cities. According to

information and statistic from the Adventure in Sarawak, (2006), the main attractions of

tourism industry in Sarawak are the longhouses, which serve as homes to the local tribe of

Sarawak. The rainforest is also a home to an incredible variety of more than 8,000 species of

flora and over 20,000 fauna, the majority of which are insects. Some of the most popular

river journeys are along the Skrang, Lemanak, Batang Ai, and Rejang rivers.

Due to the above, boat plays a very important part in Sarawak water transportation.

This means of boat transportation is limited to the popular conventional boat with underwater

propeller. The conventional boat, however, is always limited by water level and could not

compromise with the large size of unwanted objects such as woods and seaweed.

Airboat is having above water, air-propelled hull thus free from the conventional river

conditions. It is an alternative way to conventional water transportation. This study includes

the initial analysis on both hydrostatics data and static stability of the Flat bottom, Shallow

Vee and Modified hull.

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1.2 Sarawak Inland Waterway Transport

Sarawak is the largest state in Malaysia, making up to some 37.5% of the country's total area.

The State is divided into eleven Administrative Divisions. Sarawak is characterised by an

extensive network of navigable rivers shown in Figure 1.1, which potentially form an Inland

Waterway Transport (IWT) System. Sarawak has a total of 55 rivers with a combined length

of approximately 5,000 km of which 3,300 km are navigable. Of all the rivers in Sarawak, the

Batang Rajang is the most important with a total length of 567 km; it is the longest river in

Malaysia. The other major navigable rivers comprise the Batang Baram, Batang Kemena,

Batang Tatau, Sungai Limbang, Batang Lupar, Batang Sadong and Sungai Sarawak

In some rural areas, boat services are the only means of public transport. The state‟s

river transport system has great significance to the large section of Sarawak‟s population who

live in the interior and along the coast. Much of Sarawak‟s rural population relies on rivers

for transportation. Express boat services utilize the many waterways inland to get to rural

areas inaccessible by road.

Rajang River is the longest river in Malaysia. It has a total length of 760 km with a

complex river system, originated from Iran Mountains. It drains a catchment area of 51,237

km2 and consists of large network that leads to minimum gauging station. Rajang River is

connected to a few towns from upstream, namely Belaga and Kapit while towards the

downstream, namely Song, Kanowit, Sibu, Sarikei, Tanjung Manis and Daro. The Inland

water transport system plays a significant role as it is the primary means of communication

for a large section of the population living in the interior and along the coast of Sarawak.

3

There is an urgent need to develop the riverine transport in Sarawak. The impact of

developing riverine transportation will not only improve access to basic amenities, such as

health and educational services, but also indirectly enhances the local economic growth.

4

Figure 1.1 Map indicating major navigable rivers in Sarawak (DID, 2010)

.. -- KALIMANTAN

5

1.3 Essential of the Research

Airboat has great potentials in its development and application in Sarawak. Therefore more

specific researches and observations need to be done in this field. Some alternatives water

transportation are urgently needed to be worked out to meet the needs. Consequently, their

daily lives are very much constricted by the river tidal period and its geographical condition.

Water transportation is still playing a very important role in some rural areas such as Kapit

and Long Lama where land transportation is still not readily available in these areas due to

mountainous condition.

The main objective of this research is to study the alternative of water transportation

in Sarawak. Some observation on the Sarawak riverine condition has been stated in the

background study. Airboat plays a very important role for ecology researches as far as the

local riverine and mangrove ecology conditions are concerned. From the initial study

conducted, airboat can also be a useful means to emergency usage such as life saving. It can

be very useful when flood occurs at areas along Sarawak Kanan River and other tidal rivers.

Further research and modification of the airboat is carried out in this work to analyze

and simulate the Sarawak riverine condition. The challenging part for the airboat design is

that the engine used to propel the propeller must install with a certain height from the deck of

the hull, in order to improve aerodynamics efficiency. For that purpose, detail static stability

analysis of the airboat is done to improve the airboat operational safety.

Initially the airboat with Shallow Vee hull was studied and tested for its stability. The

Shallow Vee is found to have less overall stability and lower hydrostatic performances as

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compared to the Flat Bottom and Modified hull. The performance result is subsequently

verified via PROLINES simulations.

This research has taken a Shallow Vee to analyze the static stability performance and

use computer simulation to simulate another two types of hulls. Every type of hull has its

own advantages and disadvantages. Flat Bottom hull is widely used for airboat application

purpose at many countries such as United States; however in the present study, Shallow Vee

hull is proposed to investigate its performance feasibility for Sarawak water transport.

Inclining experiment has been conducted for the existing Shallow Vee hull to calculate the

Metacentric height (GM). Comparison study is carried out on the Flat Bottom, Shallow Vee

and Modified hull for overall airboat usages performance. This is done by simulation works

where the Prolines software is employed to investigate their hydrostatic and stability

performance. Results from the simulation are very important to assure their safety

requirements.

1.4 Objectives of the Research

The research emphasis on the static stability analysis for the airboat application on the three

types of hull designs, i.e. flat bottom, Shallow Vee and modified hull. These simulations

could provide useful information of airboat application under Sarawak riverine condition.

The study is achieved by considering the following objectives:

1. To conduct literature review to identify previous relevant works on water

transportation applications and it‟s applicable in Sarawak Riverine.

2. To conduct a study on the initial performance of the Shallow Vee hull airboat.

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3. To investigate and compare the advantages and disadvantages of Flat Bottom hull,

Shallow Vee hull and Modified hullbased on PROLINES simulation results toward

airboat application.

1.5 Scope of the Research

There are many aspects of research areas can be done towards airboat. Hydrostatics

parameters and factors needed to be considered, in order to have the better airboat design.

Therefore, the combination with type and size of hull, engine‟s capability, propeller applied

are major factor that need to be carefully consider. Improvement of particular aspect will give

a certain impact to the airboat performance. Besides that, investigation and improvement of

the airboat performance in the aspect of speed, stability, quietness, or maneuverability also

need to be clarified.

However, the major constrain factor to the airboat performance need to be define

earlier. During initial stage of the airboat development for Sarawak riverine application, static

stability of the airboat is consider as the bottleneck of the airboat performance and it become

foremost parameter that need our attention. According to Mabie & Reinholtz (1987),

stabilization and vibration study of the boat need to be considered in the design state and, a

number of tests need to be done to have an acceptable performance of the engine and airboat

(Michael, 2002). This including boat stability when travel in straight line and when turning,

engine air thrust measurements, etc.

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1.6 Structure of the thesis

This thesis consists of five chapters. Chapter one is the introduction, which review the

Sarawak Riverine condition, the need of river transportation development, purpose and

general overview of the project to the reader. Chapter two is the literature review of the

previous works and researches of airboat static stability. Chapter three presents the

methodology to carry out the evaluation of existing Shallow Vee hull airboat‟s static stability.

A major portion of this chapter is dealing with the usage of PROLINES software to compare

the static stability performance with Flat Bottom and modified hull. Chapter four consists of

results analysis gathered by experiment performance from inclining test and PROLINES

simulations. Chapter five is the conclusion and recommendation of this research works.