Osmosis Treatment for GRP Hulls Course
This course teaches you to diagnose and treat osmosis in glass-reinforced polyester hulls. You will learn to measure moisture, remove the gelcoat, dry the laminate and apply epoxy barriers following a complete treatment protocol.
Prior knowledge check
These are the skills this program gives you. Tick the ones you already master and we will tell you which part of the syllabus is for you.
You are starting from scratch in this subject. The program is designed precisely for that.
What is the Osmosis Treatment for GRP Hulls Course?
This short course teaches you to diagnose and treat osmosis in glass-reinforced polyester (GRP) hulls. You will understand the chemistry of polyester and how blisters form, measure moisture with meters and record readings, remove the gelcoat by mechanical peeling or blasting, dry the laminate through washing, heat and dehumidification, and apply epoxy barrier systems at the correct film thickness.
What sets this course apart: reliable diagnosis, with moisture meters and moisture maps; the complete process, from peeling and washing to drying and barrier coats; materials, covering epoxies, fillers and primers; safety, with dust, solvents and PPE; and an applied case in which you treat a 10 m hull.
Program highlights
- Reliable diagnosis: moisture meters, grid mapping and reference readings.
- Complete process: peeling, washing, drying and epoxy barrier coats.
- Materials: epoxy resins, low-density fillers and tie-coat primers.
- Drying control: infrared lamps, heated blankets and dehumidified tents.
- Safety: fiberglass dust, styrene, solvents and personal protective equipment.
- Applied case: complete osmosis treatment of a 10 m hull.
Syllabus of the Osmosis Treatment for GRP Hulls Course
5 modules. Select a module to see its content.
Fiberglass laminates and the osmotic mechanism
- 1.1. Laminate composition: gelcoat, orthophthalic, isophthalic and vinylester polyester resins
- 1.2. Glass fiber reinforcements: chopped strand mat, woven roving, combination fabrics and glass-to-resin ratio
- 1.3. The osmosis mechanism: gelcoat permeability, hydrolysis and osmotic pressure
- 1.4. Risk factors: water temperature, poor curing, air voids and long periods afloat
- 1.5. Distinguishing osmotic blisters from paint blisters and surface gelcoat defects
Hull diagnosis and inspection
- 2.1. Visual inspection after haul-out: blisters, size, distribution and acidic vinegar-smelling fluid
- 2.2. Capacitive moisture meters for GRP: relative scales, calibration and reading limitations
- 2.3. Grid-based moisture map of the hull and comparison with dry reference areas
- 2.4. Test cuts and opening of blisters, depth of damage and assessment of delamination
- 2.5. Diagnostic report and decision: preventive, surface or full treatment
Peeling and drying the laminate
- 3.1. Removing antifouling and gelcoat with a mechanical peeler, blasting or sanding
- 3.2. Opening and washing blisters, high-pressure freshwater washing to extract glycols
- 3.3. Natural drying, infrared lamps, heated blankets and tents with dehumidifiers
- 3.4. Monitoring drying with a moisture meter: reading curve and criteria for a hull ready to coat
- 3.5. Environmental control: temperature, relative humidity and dew point throughout the process
Rebuilding and epoxy barrier
- 4.1. Repairing damaged laminate with fabrics and epoxy or vinylester resin
- 4.2. Fairing with low-density epoxy fillers, sanding and surface preparation
- 4.3. Epoxy barrier systems: number of coats, overcoating intervals and curing temperature
- 4.4. Measuring wet and dry film thickness and controlling application quality
- 4.5. Tie-coat primer for antifouling and technical data sheets of paint systems
Prevention, safety and practical case
- 5.1. Preventive treatment on new or sound hulls: epoxy barriers and periodic checks
- 5.2. Safety: fiberglass dust, styrene, solvents, masks, ventilation and PPE
- 5.3. Management of gelcoat waste, dust and containers in line with environmental regulations
- 5.4. Planning times and material costs, and documenting the treatment for the client
- 5.5. Practical case: diagnosis and complete osmosis treatment of a 10-meter hull
Duration and format of the Osmosis Treatment for GRP Hulls Course
It is 300 hours. Tell us how many you can study each week and we will tell you when you will really finish.
This is the pace at which most students finish. It fits well with the installment plan.
Academic leadership and faculty
The Navalis teaching team: working professionals who teach and supervise the programs.
Dr. Marina AlcoverAcademic Director and Head of Quality Assurance
Eng. Diego CifuentesSenior Lecturer in Naval Welding and Non-Destructive Testing; Head of QA/QC for Welded Joints
Capt. Javier Abaroa (MCA)Senior Lecturer in Ship Handling, Electronic Navigation (ECDIS/Radar/ARPA) and GMDSS; STCW Compliance and Bridge Resource Management Coordinator
Dr. Pau FerrerSenior Lecturer in Naval Architecture and Simulation; Director of the Hydrodynamics and CFD Laboratory
Dr. Nuria LlobregatSenior Lecturer in Marine Meteorology, SAR and Operational Safety; Navigation Risk Management Coordinator
Eng. Javier BañulsSenior Lecturer in Electrical Engineering, Automation and ETO Engineering; Electronic Integration and Engine Alarms Coordinator
Eng. Sofía MarquinaSenior Lecturer in Materials, Composites and Corrosion Protection; Coordinator of the Advanced Paints and Coatings Line
Eng. Tomás RieraSenior Lecturer in Propulsion, Alternative Energy and Hybrid Systems; Energy Performance and Vibration CoordinatorObjectives of the Osmosis Treatment for GRP Hulls Course
Career opportunities after the Osmosis Treatment for GRP Hulls Course
Questions about the Osmosis Treatment for GRP Hulls Course
No. Many blisters are in the paint or are surface defects. The course teaches you to tell them apart through inspection, test cuts and moisture measurement.
Anything from weeks to several months, depending on the laminate, the climate and the drying method. The course covers how to speed up and control the process with periodic readings.
It gives relative readings, not an absolute percentage of water. That is why the course teaches you to work with moisture maps and reference areas.
Largely, yes. The course covers preventive epoxy barrier treatments and the recommended periodic inspections.
The fluid inside osmotic blisters contains glycols and other by-products that keep attracting water. Module 3 explains how repeated washing removes them before drying begins.
The course is taught online and comprises 300 hours of study across 5 modules of about 60 hours each and ends with an applied practical case.
More programs in Shipyard and finishes
Admission process
No waiting for a call back. If your documents are in order, you can enroll in the same session.
- Profile: aimed at boatyard technicians, laminators, marine painters and boat owners who need to diagnose and treat osmosis in fiberglass hulls.
- Language: sufficient command of English to follow the classes and the technical documentation.
- Technical resources: a computer with a stable internet connection, an up-to-date browser and a camera for live sessions and project presentations.
- Admission: enrollment is open all year round; online application, review of your profile and a short interview with the academic team.
- 01ApplicationYour details, background and documents.
- 02Instant reviewWe check that everything is complete and in order.
- 03EnrollmentChoose full payment or instalments and reserve your place.
Admission is provisional until the committee validates the documents provided. If you do not meet the requirements, the full amount is refunded.
Ask us before you enroll
Leave your details and admissions will write to you to answer any questions. If you are already sure, you can apply and pay in the same session.