Improving yacht hull inspections with infrared imaging
One of the maritime industry leaders in Thermography, Geo Therm Ltd has over the past 20 years provided impartial thermal infrared inspections for all forms of surface watercraft. In his latest article for ONBOARD magazine Tony Dale Geo Therm Ltd Company MD discusses the use of thermal imaging to provide enhanced hull inspections, rather than traditional labour intense methods.
A typical tried and tested technique to differentiate structural integrity in fibre-reinforced plastic (FRP) hulls is to apply a consistent low-impact force using a plastic or rubber headed sounding hammer. This impact-echo response is immediate, exciting vibrations of delamination and differing tonal reverberations evident as a hollow sound for voids.
Although effective, the technique needs a sensitive ear and must be repeated over the entire hull surface by a competent inspector. This technique can potentially lead to unwarranted damage, furthermore, it is time consuming and difficult to uncover the total damaged area by hammer tapping alone – and often facilitated with moisture meter readings and exploratory destructive testing such as core sampling, gel-coat removal, drilling and grinding to differentiate the extent of the affected area.
Thermography or thermal imaging is very different, it is a non-invasive technique using thermal cameras to sense the invisible infrared (IR) range in the electromagnetic spectrum to detect, display and record in real time the surface thermal patterns across its entire field of view, to locate and map damaged areas and moisture intrusion.
Thermal IR imaging cameras convert heat emitted from a surface into a two-dimensional false-colour image called a Thermograph, wherein thermal patterns (and accurate temperature values) are represented by varying shades of grey or colour, that emphasise thermal anomalies deviating from the norm.