Modern yachts and many small craft are built from composite materials, and their structural performance depends on choices made at every scale, from fibre direction in a single ply to the way a keel load is carried into the hull. The course gives students of yacht design and working marine professionals a grounded introduction to building and engineering with composites. It covers the roles of fibre, resin, core and interface, the directional behaviour of laminates and the effect of ply order, sandwich action and its failure modes, load paths through hull, deck, bulkheads, rig, keel and appendages, moulding processes and the origin of defects, bonded and bolted joints, in-service ageing and damage, and how inspection, repair choices and design allowables feed back into structural design.
Course at a glance: Duration 20 hours · Self-paced online · 10 sections, 40 lessons, a 234-page downloadable course book
What you will learn
- Explain how fibres, resins, cores and interfaces contribute to composite marine structures.
- Explain fibre direction, anisotropy, ply properties and stacking sequence and how loads pass through a laminate.
- Explain sandwich panel mechanics, core selection and the detailing of edges, inserts and openings.
- Trace load paths through yacht hull and deck structures, bulkheads, floors, masts, keels and appendages.
- Evaluate moulded composite workflows, including wet lay-up, infusion and prepreg, and the process causes of defects.
- Explain the principles of adhesive bonded joints, surface preparation and mechanical or hybrid fastening.
- Apply basic principles to degradation, damage, inspection, repair decisions and design allowables.
Inside the course: a high-level summary, section by section.
Constituents and interfaces
The course begins with the building blocks of composite marine structures. Fibres carry load and provide stiffness, resins bind the fibres, transfer load and protect them, and cores separate skins to increase bending stiffness. Interfaces between fibre and resin, and between skin and core, are where many problems start. Poor fibre wet-out, contamination or inadequate bonding weaken the structure, so understanding these interfaces is as important as knowing the properties of the materials themselves.
Laminate mechanics
Fibre direction makes composites anisotropic: they are strong and stiff along the fibres and much weaker across them. Ply properties combine into laminate response, and stacking sequence and symmetry determine whether a laminate twists or warps under load or during cure. The course explains how in-plane and bending loads pass through a laminate and why balanced, symmetric lay-ups are generally preferred.
Sandwich structures
Sandwich panel mechanics explain how skins carry bending as tension and compression while the core carries shear. Core selection is treated as a matching problem rather than a popularity contest. Foam, balsa and honeycomb cores are compared on stiffness, strength, weight, response to moisture and toughness, with the choice driven by panel loading, span between supports, environment and the local crushing, shear and wetting the panel will face. Skins, cores and shear interactions determine failure modes such as core shear, skin wrinkling and indentation. Edges, inserts and openings require particular care because they disrupt the sandwich: at a discontinuity the load path becomes local, stress concentrates in the skins and bearing, peel, pull-out or shear can develop. Reinforcement is most effective when it addresses how load is transferred, not when it merely adds thickness: well-designed details distribute point loads, re-establish load paths where the core is cut, avoid abrupt stiffness changes and account for the failure modes nearby. A sandwich design check consolidates the section.
Yacht structures
Yacht load paths explain how rig, keel, hydrostatic and slamming loads flow through the structure. Hull and deck structures, bulkheads, floors and webs work together to carry these loads, and masts, keels and appendages introduce concentrated loads that must be spread safely into the hull. Connections and terminations, where structural members meet or end, are common sources of failure. Designing for impact loads, such as grounding, is discussed. A preliminary structure task asks learners to lay out a basic structural arrangement.
Manufacturing and defects
Moulded composite workflows are compared: wet lay-up, resin infusion and prepreg with controlled cure. Each offers different fibre fractions, consistency and cost. Defects and their process causes, such as voids, dry spots, resin-rich areas, wrinkles and poor bonding, are examined, so that learners can link a defect to its likely origin and prevention.
Joints
Adhesive bonded joints are widely used in composite yachts, joining hull to deck, bulkheads to hull and fittings to structure. The course explains how bonded joints carry load, why surface preparation is critical, and when mechanical fasteners or hybrid bonded and bolted joints are more appropriate.
Degradation, damage and repair
Marine degradation mechanisms, including moisture uptake, UV exposure and heat cycling, and fatigue, affect long-term performance. Water can gradually enter laminates and cores, most often at edges, fittings and damaged coatings, adding weight but also reducing stiffness, weakening bonds and allowing hidden damage to grow. Sunlight and heat act mainly on exposed surfaces, coatings and gelcoat. A recurring theme is that visible surface symptoms can point to hidden damage deeper inside, so inspectors need to trace how service conditions act on different parts of the structure. Damage, cracks and delamination are explained along with how they grow. Inspection and repair decisions require judging whether damage is cosmetic or structural and choosing an appropriate repair approach.
Design allowables and rules
The last section shows the steps that turn test results into numbers a designer can actually use, via evidence, factors and class rules. An allowable applies to one material system in one condition, and it is neither an unprocessed test figure nor the best value a supplier quotes. An early sizing of a panel, beam or stiffener is believable only when allowable, safety factor and applicable rule agree.
Designing, building and maintaining as one process
A key message of the course is that composite structures cannot be designed in isolation from how they are built and maintained. The designer’s choice of laminate and core assumes a certain fibre fraction and bond quality, which depends on the builder’s process and workmanship. Joints and inserts must be designed so they can actually be made and inspected. Over the life of the yacht, damage and degradation must be detected and repaired in ways that restore the original load paths. Learners who understand this whole cycle can make better design decisions, specify more realistic manufacturing requirements and judge repair proposals with confidence.
Why this matters in practice
Yacht designers, builders, surveyors and repairers all work with composite structures. Understanding materials, laminate and sandwich behaviour, load paths, manufacturing, joints and damage allows them to design efficient structures, build them reliably, inspect them effectively and make sound repair decisions.
Key takeaways
You leave able to explain composite constituents and interfaces, laminate and sandwich mechanics, yacht structural load paths, manufacturing workflows and defects, bonded and fastened joints, degradation and damage, and how design allowables and rules underpin safe composite structures.
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 (8 in total) so you can confirm you can apply each method before moving on. A 234-page course book can be downloaded and printed for offline reading and later reference.
Course contents
- Constituent Materials: Reinforcement Forms and Roles; Resins, Cores, and Interfaces
- Laminate Behavior: Fiber Direction and Anisotropy; Ply Properties and Laminate Response; Stacking Sequences and Symmetry; Loads Through a Laminate
- Sandwich Structures: Sandwich Panel Mechanics; Core Types and Selection; Skins, Cores, and Shear; Edges, Inserts, and Openings; Local Reinforcement Strategies; Sandwich design check
- Structural Design Practice: Yacht Load Paths; Hull and Deck Structures; Bulkheads, Floors, and Webs; Masts, Keels, and Appendages; Connections and Terminations; Designing for Impact Loads; Preliminary structure task
- Manufacturing Processes: Molded Composite Workflows; Wet Layup and Infusion; Prepreg and Controlled Cure; Defects and Process Causes
- Bonding and Assembly: Adhesive Bonded Joints; Bonding Surface Preparation; Mechanical Fasteners and Hybrids
- Durability and Failure: Marine Degradation Mechanisms; Damage, Cracks, and Delamination; Inspection and Repair Decisions
- Standards and Safety: Design Allowables and Rules
- Integrated Yacht Concept: Key Takeaways
Who this course is for
It suits yacht design students and marine professionals such as designers, builders, surveyors and repairers who want a sound working grasp of composite structures. Basic structural mechanics knowledge is helpful.
Frequently asked questions
How long does Composite Materials in Marine Structures 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 10 sections with 40 lessons, moving from foundations to applied methods, as summarised above.
Is there material to keep after the course?
Yes. A downloadable 234-page course book accompanies the lessons for offline reading and later reference.
How is progress checked?
Each main section closes with a graded quiz (8 in total, with a pass mark of 80%). 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: K02 – Marine Structural Composites & High-Speed Craft; K01 – Recreational and High Speed Craft; I01 – Sail Yacht Design and Technology; A04 – Project Introduction to Hydromechanics
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Study at your own pace and work through the full course material, worked examples and section quizzes. Enrol in K03 – Composite Materials in Marine Structures →
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