Derricks and cranes can be tested in two ways:
- Static test – In static test, a spring balance is shackled to an eye on deck and the derrick and crane runis ner wire is used to pull on it till the proof load is reached. This method is normally used for smaller capacity derricks and cranes.
- Dynamic test – In dynamic test the pre – weighed load equal to the proof load is brought by a barge or truck to the ship side from where it is lifted by the derrick or crane. The derrick is swung side to side and up and down with the weight suspended after testing, it is most important to check the components of the lifting gear for any elongation, deformation or fracture.