Introduction to percussion testing
Percussion testing, also known as ‘tapping,’ is a valuable non-destructive inspection method for assessing the condition of fiberglass hulls, decks, and other composite vessel components. Widely used across various industries, including aviation and space exploration, tapping remains a reliable technique for identifying structural issues.
Application in marine inspections
In boatyards, percussion testing evaluates the condition of laminates on fiberglass vessels. This method, which can also be applied to wood and other materials, focuses on detecting delamination and voids. Laminates typically comprise several layers, such as fiberglass material with resin, gelcoat, and coring materials. Separation of any of these layers can occur for various reasons. Tapping identifies these separations without damaging the vessel, relying on the trained ear of an experienced surveyor.
Importance of percussion testing
Many boats feature cored decks, hulls, stringers, and other parts with materials like balsa, foam, or plywood between layers of fiberglass laminate. Timber coring materials, such as balsa or plywood, can deteriorate due to fungus or rot, and percussion testing can detect this deterioration. Tapping stringers and transoms, especially in smaller boats, can reveal compromised coring materials. This non-destructive method ensures that potential issues are identified without causing further damage.
Tools and techniques
Surveyors often use a non-metallic hammer or tape over the metal part of the hammer during percussion testing to avoid marking the vessel. While tapping is a time-honoured and effective non-destructive inspection method, it is one of many techniques used to assess a vessel’s condition. Additional methods include flexing under pressure, visual inspections for discoloration or cracks, and listening for crackling sounds when stepping on suspect areas. Moisture meters also help assess laminate conditions, but their accuracy depends on calibration, environmental conditions, and the operator’s interpretation of readings.
Choosing the right surveyor
Selecting a surveyor proficient in various inspection techniques, including percussion testing, is crucial for a comprehensive assessment of your vessel. A knowledgeable surveyor understands both the inspection methods and the construction techniques of the vessel, ensuring accurate and reliable evaluations. Aquamarine Services is your trusted partner for all marine surveyor needs, offering a wide range of expert services to ensure your vessel’s safety, reliability, and performance.
Conclusion
Percussion testing is an essential tool for maintaining the integrity of your vessel. Regular inspections using this method can prevent minor issues from becoming major problems, ensuring your vessel remains safe and seaworthy.
