Before detailed design begins, naval architects must estimate hull form, weight, resistance, cost and specialised features with only limited information. This third part of the Naval Architecture and Ship Production Technology series covers the preliminary-design methods used to do that. It shows how regression methods give first estimates of hull-form coefficients, how lightship weight and deadweight are broken down and iterated, and how resistance is estimated with the Holtrop and Mennen method. It then links technical choices to ship economics through newbuilding cost, crew and operating cost models and required freight rate. The course also covers CAD fundamentals, from offset tables to NURBS surfaces, geometric transformations and Bezier curves, general arrangement, hull alteration methods, rudders and bilge keels, and closes with the design fundamentals of gas carriers.
Course at a glance: Duration 20 hours · Self-paced online · 8 sections, 40 lessons, a 144-page downloadable course book
What you will learn
- Estimate preliminary hull-form coefficients using regression-based methods and designer judgement.
- Break down lightship weight and deadweight and iterate towards a consistent concept.
- Explain the components of ship resistance in the Holtrop and Mennen method.
- Compare newbuilding cost, crew cost and operating cost models, and use required freight rate to rank designs.
- Explain how CAD, geometric transformations, NURBS and Bezier curves support hull and arrangement development.
- Assess hull alteration methods, rudder types and bilge keels for concept-stage design.
- Describe gas carrier trades, LNG containment systems and IGC tank classes.
Inside the course: a high-level summary, section by section.
Hull form, weight and resistance estimation
The course begins with regression methods for hull-form coefficients. Statistical relationships derived from existing ships give first estimates of block, prismatic, midship and waterplane coefficients from speed and size. Different regressions can give slightly different answers, so the course stresses that regression is a guide, not a substitute for the designer’s judgement about whether an estimate suits the intended ship type.
Weight estimation follows. Lightship weight is divided into steel, outfit and machinery groups, each estimated from principal dimensions and power. Deadweight is then the difference between displacement and lightship, and if the estimated deadweight does not meet the requirement, the dimensions must be adjusted and the calculation repeated. This iteration is the essence of concept design.
Resistance is estimated with the Holtrop and Mennen method, which separates total resistance into frictional resistance, adjusted with a form factor for hull shape, wave-making resistance derived from hull-form parameters and Froude number, and further components for appendages, the bulb, an immersed transom and model-ship correlation. A short lesson on container capacity estimates shows how the same regression approach applies to cargo capacity.
Ship economics
The second section links technical design to commercial outcomes. Newbuilding cost is estimated by cost group, using coefficients that depend on dimensions, weight, installed power and ship type, with allowances for yard overhead, profit and owner-furnished items. Crew cost models and operating cost formulae then cover the annual running cost of the ship, of which fuel is only one part.
Required freight rate brings these together: the freight rate the ship must earn to cover capital and operating costs over its life. A design that looks technically excellent can still be weak if its costs lead to an uncompetitive freight rate. The influence of flag and registry on crew costs, taxation and regulation is also discussed.
CAD fundamentals
The CAD section traces hull definition from offset tables and manual fairing, through early computer fairing of offset data, to modern definition of the hull as mathematical surfaces such as NURBS, which make geometry smooth, editable and consistent for design and production. A typical hull modelling workflow is outlined, followed by practical CAD concepts: coordinate systems, layers for organising drawing information, model space and paper space, and drawing standards that make outputs consistent and readable.
Geometric modelling and general arrangement
Geometric transformations, including scaling, rotation and translation, are the basic operations for reshaping and positioning geometry. Written in homogeneous coordinates and matrix form, they can be combined into a single operation, and the course shows why the order of operations matters. Bezier curves are introduced as the building block of many CAD curves: the endpoints are fixed, while interior control points pull the curve into shape, rather like magnets acting on a flexible strip. General arrangement then applies these tools to the layout of the ship, including accommodation standards, where cabin area depends on rank and ship size.
Hull alteration, rudders and bilge keels
Hull alteration methods allow designers to adapt an existing hull form rather than starting from scratch. The course explains the goals of alteration, classical methods such as the one-minus-prismatic approach for changing prismatic coefficient and Lackenby’s method for shifting the longitudinal centre of buoyancy, the use of parallel mid-body to change length, and worked alteration cases. Rudder types, including balanced and partially balanced designs, are compared by how their geometry affects steering effectiveness, while profiles and torque explain how section shape and balance determine the steering gear requirements. Bilge keels are covered as a simple and effective means of roll damping.
Gas carrier design
The final section introduces the gas trade and the design of LNG and LPG carriers. LNG containment systems, including independent and membrane types, are compared, and the IGC tank classes are explained. LPG specifications and the terminal interface show how cargo properties and port equipment shape ship design. Because liquefied gases are carried either very cold, under pressure or both, containment choice affects hull dimensions, structural arrangement, insulation, boil-off handling and the materials used throughout the cargo system, so it is one of the earliest and most consequential decisions in a gas carrier project.
Why this matters in practice
Concept design decisions are made quickly and on limited data, yet they commit most of a ship’s eventual cost and performance. Engineers who can produce sound first estimates of hull form, weight, resistance and cost, and who understand the assumptions inside each regression, can compare options rapidly and spot when a number looks wrong. Familiarity with CAD geometry and hull alteration methods means an existing parent hull can be adapted with confidence, saving time and model-testing cost. The economic tools, especially required freight rate, give a common language for discussing designs with owners and financiers, while the gas carrier material introduces one of the most technically demanding ship types in service today.
Key takeaways
You leave with a practical toolkit for preliminary ship design: estimating hull form, weight, resistance and cost, ranking designs economically, using CAD and geometric modelling, adapting hull forms and appendages, and understanding the fundamentals of gas carrier design.
How you study
The course is delivered fully online and is self-paced, so you can fit roughly 20 hours of study around professional commitments. Lessons combine clear explanation with examples, diagrams and short interactive checks, and the main sections end with graded quizzes (6 in total) so you can confirm you can apply each method before moving on. A 144-page course book can be downloaded and printed for offline reading and later reference.
Course contents
- Preliminary Estimation: Hull Coefficient Regressions; Preliminary Weight Groups; Deadweight and Iteration; Holtrop and Mennen; Container Capacity Estimates
- Ship Economics: Newbuilding Cost Groups; Crew Cost Models; Operating Cost Formulae; Required Freight Rate; Flag and Registry
- CAD and Hull Modeling: From Offsets to NURBS; Hull Modeling Workflow; CAD Coordinates and Layers; Model and Paper Space; Drawing Standards
- Geometry and GA: Geometric Transformations; Transformation Order; Bezier Curve Basics; de Casteljau Method; General Arrangement
- Hull Alteration and Appendages: Alteration Goals; Classical Alteration Methods; Parallel Mid-Body; Worked Alteration Cases; Rudder Types; Profiles and Torque; Bilge Keels
- Gas Carrier Design: Gas Trade Context; LNG Containment Systems; IGC Tank Classes; LPG Specifications; Terminal Interface
- Summary: Key Takeaways
Who this course is for
This course suits engineering graduates and practising engineers who want a refresher in concept-stage ship design methods, including naval architects, design engineers, ship economists and CAD specialists in shipyards and consultancies. It is the third of a four-part series and can be taken alone or alongside the other parts.
Frequently asked questions
How long does Naval Architecture and Ship Production Technology (Part 3 of 4) take?
The course is designed for about 20 hours of study. It is self-paced and fully online, so you can spread it over a few weeks or complete it more quickly.
What is covered?
The course is organised into 8 sections with 40 lessons, moving from foundations to applied methods, as summarised above.
Is there material to keep after the course?
Yes. A downloadable 144-page course book accompanies the lessons for offline reading and later reference.
How is progress checked?
Each main section closes with a graded quiz (6 in total). The quizzes test understanding of the concepts and methods explained in the lessons rather than memorisation, and you can review the relevant lessons before attempting them.
Can I record this study for my own professional development?
Yes. The course notebook includes a self-assessment of the course objectives before and after study, a reflection page and a learning log, which you can use to keep your own record of professional development.
Duration: 20 hours
Related courses: A11 – Naval Architecture and Ship Production Technology (Part 2 of 4); A13 – Naval Architecture and Ship Production Technology (Part 4 of 4); A10 – Naval Architecture and Ship Production Technology (Part 1 of 4); B06 – Resistance & Propulsion
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Study at your own pace and work through the full course material, worked examples and section quizzes. Enrol in A12 – Naval Architecture and Ship Production Technology (Part 3 of 4) →
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