Good ships start as well-reasoned concepts, and the step from a first idea to a credible preliminary design is where many of the most important decisions are made. This course guides you through that feasibility-to-preliminary design process as practised in naval architecture education and the design office. Drawing on real course policies, design briefs, grading checklists and authentic student design projects, it shows why the design sequence exists, how a mission statement and parametric analysis shape a concept, and how principal dimensions, weights and hydrostatics are tested for internal consistency. It then explores stability assessment through GZ and cross curves, and structural design through rule-based scantlings and longitudinal strength logic, before closing with the professional judgement needed to assemble a design package that will stand up to review.
Course at a glance: Duration 20 hours · Self-paced online · 7 sections, 24 lessons, a 89-page downloadable course book
What you will learn
- Explain the role of feasibility and preliminary design within the wider ship design process.
- Write a mission statement that genuinely steers hull form, arrangement, structure and ballast decisions.
- Build a parametric basis for a new concept using reference vessels and design lanes.
- Interpret principal dimensions, weights and centres, and hydrostatic data to judge whether a design is reasonable.
- Read GZ curves and cross curves, identify mismatches and assess dynamic stability.
- Distinguish rule-based scantlings from designer’s choices and identify which members contribute to longitudinal strength.
- Organise a professional design submission that meets authentic review standards.
Inside the course: a high-level summary, section by section.
Design sequence and deliverables
The course begins by explaining why ship design follows a sequence at all. Feasibility design asks whether a concept can meet its mission at all; preliminary design develops it to the point where dimensions, weights, stability and structure are consistent and can be reviewed by others. As the work progresses, three things change together: how complete the design is, who it is for, and what kind of deliverable is expected. Understanding those shifts helps a designer move from guided concept building to producing a package fit for professional review.
The section uses authentic briefs to show what that package looks like. Individual and team assignments, formatting standards for drawings and reports, rules on citing reused spreadsheets and tools, and the criteria used to judge designs all reveal that presentation is part of the professional standard, not an afterthought. Judged awards are discussed in terms of what they reward, such as technical competence and the overall quality of the design reasoning.
Mission and parametrics
The heart of early-stage design is the mission statement. It is not a marketing slogan but the filter that shapes every downstream choice, from hull form and rig to ballast, structure and arrangement. The course shows how to write one that is specific enough to guide decisions and how to translate it into a parametric basis for the design.
Parametric analysis uses data from comparable vessels to establish realistic ranges for key ratios and dimensions. You learn to build design lanes, select reference vessels close to your concept and use them to refine early estimates. A detailed comparison of two real sail training vessel designs illustrates how different missions lead to different proportions, overhangs and ratios, and why the numbers only make sense when read alongside the mission they serve. A mission-statement exercise lets you apply the method to your own concept.
Principal dimensions, weights and hydrostatics
Once a concept has numbers, the next task is to test whether those numbers are consistent. The course explains how to read a table of principal dimensions and what each ratio implies for performance and capability. It then examines weights and centres across loading conditions. A key insight is that the heaviest condition is not always the worst for stability: as fuel and water are consumed, the vertical centre of gravity can rise, so the burnt-out or light condition may govern.
Hydrostatic reasonableness checks bring these strands together. Indicators such as capsize screening factors, motion comfort ratios, hull speed relative to waterline length and ballast ratio should all look plausible for the intended use. When one value looks odd while the others look normal, that is often the clue to a data or calculation error. A data-debugging exercise builds the habit of interrogating design data rather than accepting totals at face value, a skill that is valuable in any design review.
Stability assessment
The stability section focuses on reading results in context. The GZ curve, which plots the righting arm against heel angle, shows the maximum righting arm, the angle at which it occurs and the angle of vanishing stability, beyond which the vessel will not recover. A strong offshore design should show both a substantial righting arm and a survivable range of heel.
Cross curves of stability, which present righting levers for a range of displacements, are introduced as the source data from which GZ curves are built. The course discusses how apparent contradictions between different stability outputs usually arise from differences in loading condition, units or normalisation, and how a reviewer should question and interpret them. Dynamic stability, represented by the area under the GZ curve, and the role of hull section shape complete the picture.
Structural design
Structure is the final technical strand. Using a real design example, the course separates structural specification into two kinds of decision. Some are design choices made by the designer, such as the hull construction method and the material of the ballast keel. Others are rule-based scantlings, such as shell thickness, framing and fastening sizes, determined by classification rules. Recognising which is which clarifies where judgement is exercised and where compliance is demonstrated.
Longitudinal strength logic then explains which structural members contribute to hull-girder strength. Continuous longitudinal members such as the shear strake, deck and longitudinal bulkheads count, while discontinuous items such as stanchions do not. Understanding why helps designers estimate section modulus correctly and avoid over- or under-estimating hull strength.
Professional design judgements
The course closes by bringing technical results and professional practice together. Good preliminary designs are internally consistent, transparently documented and honest about their assumptions and uncertainties. You learn to present design decisions with their justification, cite tools and sources, and anticipate the questions a reviewer will ask. These judgements are what turn a collection of calculations into a design that others can trust and build on.
Why this matters in practice
Most of the cost and capability of a ship is fixed in the earliest design stages, when the least information is available. Errors made at feasibility, such as an unrealistic weight estimate, a misread stability curve or a mission statement that does not really constrain the design, propagate into every later stage and become expensive to correct. The habits taught in this course, including checking data for internal consistency, reading stability results in context and separating rule-based decisions from design choices, are exactly the habits that experienced reviewers look for. They apply equally to small craft, sail training vessels and larger naval or commercial ships, and they make a designer more effective when working with class societies, owners and colleagues in a design team.
Key takeaways
You leave with a clear understanding of the feasibility-to-preliminary design workflow: how a mission drives parametrics, how dimensions, weights and hydrostatics are checked for consistency, how stability and structure are assessed, and how the results are packaged for professional review.
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 (5 in total) so you can confirm you can apply each method before moving on. A 89-page course book can be downloaded and printed for offline reading and later reference.
Course contents
- Design Sequence and Deliverables: Why the Sequence Exists; Individual and Team Briefs; Assessment and Awards
- Mission and Parametrics: Mission Statements in Practice; Building Design Lanes; Comparing Isis and Rosamunda; Mission Statement Exercise
- Dimensions and Hydrostatics: Reading Principal Dimensions; Weights and Centers; Hydrostatic Reasonableness Checks; Data Debugging Exercise
- Stability Assessment: Reading the GZ Curve; Cross Curves and Mismatches; Dynamic Stability and Section Area
- Structures and Materials: Rule-Based Scantlings; Longitudinal Strength Logic; Professional Design Judgments
- Summary: Key Takeaways
Who this course is for
This course suits engineering graduates and practising engineers who are moving into ship or yacht design, or who want a structured refresher on early-stage design methodology. It is valuable for junior naval architects, design engineers in shipyards and consultancies, and engineers who review concept designs on behalf of owners or operators. Familiarity with basic hydrostatics and stability is helpful.
Frequently asked questions
How long does Feasibility to Preliminary Naval Ship Design 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 7 sections with 24 lessons, moving from foundations to applied methods, as summarised above.
Is there material to keep after the course?
Yes. A downloadable 89-page course book accompanies the lessons for offline reading and later reference.
How is progress checked?
Each main section closes with a graded quiz (5 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: A08 – Integrated Ship Design Project; A14 – Design of Advanced Marine Vehicles; A15 – Modularity and Platform-Based Ship Design; A18 – Naval Architecture Fundamentals
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Study at your own pace and work through the full course material, worked examples and section quizzes. Enrol in A07 – Feasibility to Preliminary Naval Ship Design →
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