Osmosis is a process affecting all laminates in marine environments, including those made of epoxy. During the manufacturing of boats, small voids can form between the gelcoat and the first layer of laminate. Water molecules pass through the laminate, condense in these voids, and start breaking down the components within the laminate. This breakdown releases various acids, alcohols, and metallic compounds, which contribute to the formation of osmosis blisters. These blisters can cause noticeable distortions or damage to the laminate or gelcoat over time.
At ACP Surveyors, we provide thorough osmosis and moisture inspections to assess the condition of your boat’s laminate. Our process involves:
Visual Gelcoat Assessment:
We begin by removing antifouling from several test patches around the boat’s underbody. This planing technique leaves the gelcoat intact while exposing any high spots, which can indicate the early stages of blistering.
Moisture Readings:
Using the advanced Sovereign Quantum capacitance-type moisture meter, we take moisture readings from the hull. These readings must be interpreted considering several factors, such as the type of resin used and the duration the vessel has been ashore.
Resin Types:
Boats made with orthophthalic resins (common until the mid-1990s) tend to absorb and retain moisture longer. Boats with isophthalic and vinylester gelcoat resins (used since the mid-1990s) typically show satisfactory moisture readings sooner after being lifted out of the water.
Time Ashore:
Moisture readings can vary significantly based on how long the vessel has been out of the water. For example, boats ashore for less than two weeks in summer or four weeks in winter may still show high moisture readings due to surface moisture.
Epoxy Coatings:
Epoxy coatings, often applied with a brush or roller, can contain micro fissures and voids that absorb moisture, doubling the drying time.
Interpreting Moisture Readings
Moisture readings are critical in determining the laminate’s condition but must be contextualized:
0-15:
Dry for all practical purposes.
16-20:
Some moisture present but not significant.
21-30:
Medium moisture; higher levels within this range indicate a growing risk of moisture-related defects.
31-45:
High moisture; significant risk of undetected moisture-related defects.
46-60:
Very high moisture; typically accompanied by visible defects.
>61:
Extremely high moisture; indicative of potential laminate damage and osmotic blistering.
We advise laying up the vessel ashore for 2 to 4 months each winter and conducting annual inspections of the underwater sections to monitor and address any osmosis-related defects. Regular maintenance and timely inspections can significantly mitigate the risk of severe osmosis damage, ensuring the longevity and performance of your vessel.
For comprehensive osmosis inspections and professional advice on maintaining your boat’s laminate integrity, contact ACP Surveyors today.
In addition to our extensive boat damage survey, ACP SURVEYORS offers a range of supplementary services to support you during this challenging time. These services include consultations and guidance on selecting reputable repair facilities and contractors.
Get in touch with our surveyors to arrange a meeting about your upcoming osmosis survey:
The reputation of our company is grounded in the trust of our clients. Our professionalism, clear communication process and proactive collaboration have helped us build long-term relationships with the majority of our customers.
Our approach is based on an uncompromising sense of ethics, the highest standards of quality and the use of cutting-edge technology.
We offer our expertise in project management of new builds, repairs, refits, valuations, technical and organisational audits, and consulting.
We guide our clients through complex processes with specialist advice and technical support. Our extensive experience is complemented by seamless efficiency that ensures a perfectly smooth process for our clients.
