In this video of a survey I did a couple of days ago you can see an example of a tap test.
A tap test is a non-destructive inspection technique used to assess the condition of a vessel’s materials by checking the sound produced by an object hitting the surface.
This technique is often used to assess composite materials, metal alloys and structures in general.
During the test, the surface of the material is struck with a hammer. The force and manner of striking can vary, but usually these are light, controlled blows.
The marine surveyor checks the duration, intensity and tone of the echo.
The echo generated by the blow may reveal variations in the density, structure or any discontinuities in the material. For example, the presence of air bubbles, delaminations or other imperfections may influence the echo generated.
The assessor can use tap testing to identify specific areas of a material that may require further analysis or inspection.
This is a quick and simple technique, but requires some experience on the part of the ship surveyor in evaluating the echo generated and interpreting the information obtained.
It should be noted that this technique is best suited for detecting surface imperfections and is not as sensitive as other more advanced non-destructive inspection methods, such as ultrasound or thermographic analysis.