Verification of draft markings on flying dolphin
The scope of this project was to verify the designed and marked position of draft marks after extensive metal works performed on the hull and the first sea trials on a flying dolphin. The measurement process was completed in 1 working day. At first, a local control network was established for the measurement of detail points and relevant markings. Some of the design criteria of the network that were taken under consideration were the following:
- geometrical strength (concerning the available working areas)
- visibility of the majority of control points between different station setups
- minimisation of errors on desired directions (prescribed precision)
- sensitivity to detect blunders and errors (reliability)
- visibility of the areas of interest
- redundancy and plethora of necessary observations
The best definition of the vessel coordinate system was feasible through the survey of all characteristic geometrical attributes such as:
- Keel line
- Structural elements
- Already marked draft and load marks
An industrial total station, Leica TDRA 6000, was selected for the measurement of the control network (with permanent, temporary retro reflectors and spherical mounted targets), the survey of detail points and the further verification of the draft marks. After the completion of the measurement process, the collected raw data were imported to the relevant metrological platform (Spatial Analyzer) for further processing.
A proper Ship Coordinate System (SCS) needed to be defined, which was accomplished by utilizing all the measured data. After the creation of coordinate frame, the verification process of the draft marks followed.
The findings on keel line and the local deviations from the design condition reveal the necessity for further actions such as geometrical adjustments etc.