Accordingly, the two parties though their meeting in Svolvær, they came to the conclusion that this method may be less comprehensive and faster in comparison to pulling the keel bolts perform, while commended that is was considered accepted 20 years ago.
At the same time, ultrasound is gaining trust, as it is going to be accepted as an alternative to the pull of keel bolts. The industry along with the DNV GL proved that this method is fruitful and brought back in the game the ultrasound checking method, making the Directorate open to accept it.
DNV GL, demonstrated how ultrasound can be used for condition monitoring of keel bolts while brought positive measurements feedback and reliable results for several typical corrosion damage. On the other hand, there are some conditions that the method doesn't follow, such as possible wear of the threads of nuts at the ends of the bolts.
Moreover, the final approval is still under consideration, since procedures must be developed to describe procedures, acceptance criteria and limitations. Additionally, the method should prove to provide measurements with acceptable accuracy and can be used without too many limitations.
The Norwegian Maritime Directorate enabled DNV GL to carry out condition checks with the use of ultrasound on keel bolts on wooden boats. If a vessel's owner wishes to use this method, he must first order control of of DNV GL and cover the cost by himself.
However, the Directorate emphasized that in a ultrasound check, the tightening of the bolts cannot be replaced, and in case of any wear is uncovered, the bolts must be tightened for replacement.
Concluding until the end of 2020, the Norwegian Maritime Directorate will assess if the results brought by ultrasound's measurements are trustworthy enough to be accepted to use it on a regular basis.