Summary
Geospatial SurveySolutions and Deri Jones & Associates (GSS/DJA) have worked with Naval Architects to provide as built surveys of a variety of different vessels in 2009. Working mainly with the Faro LS880 laser scanner, GSS/DJA can capture and model complex vessels in a short time.
Survey
GSS/DJA provided survey services working in drydocks, slipways and sheds – from Glasgow to Malta. Over the past three years we have built a reputation for supplying high quality measurement with minimal disruption to other work on the vessel. Working on behalf of Naval Architects Marine Design International Ltd (MDI), we surveyed the 75m “Lough Foyle” suction hopper dredger at the Garvel Drydocks inGreenock. Here we had to work around the waterjet blasting company cleaning the vessel for painting. Careful location of the scanner and working through lunch allowed us to record the 21 scans required to construct an accurate overview of the vessel in a day. Working with the Faro LS880, details such as hawse pipe, bow thruster and hull penetrations could be recorded quickly and accurately.
A second project on behalf of Advanced Yacht Services in Malta saw GSS/DJA fly in with the Faro LS880 and capture the 35m expedition yacht Drenec on the slipway. Due to be relaunched, GSS/DJA captured the hull,superstructure and tow internal compartments of the vessel in 13 hours on site, again working around teams repairing steelwork, hydraulics and paintwork.
In the space of 21 hours, we captured in the region of 1.8 billion points of data on these two vessels, giving a clear and detailed point cloud model to work from to create CAD data.
The next port of call saw the GSS/DJA team on the south coast of England, first Cornwall, then the Isle of Wight, capturing GRP moulds for different clients. To achieve the highest accuracy on these smaller projects, we used our Leica TS1203 total station, taking off individual points to act as a basis for CAD modelling.
The 8m RIB hull required some 8 hours of measurement, while the simpler cabin superstructure took some 4 hours, all recorded on site at the clients premises.
Processing
The downloaded scan data is processed using Faro's SCENE software – cleaning out unwanted areas of data, aligning the scans to the control network of survey points recorded using the total station and filtering any irregularities in the data. Once processed to a coherent data set, Pointools is used to import the scan data for viewing and use in the modelling package Rhino3D.
All steps in this process are checked for accuracy to ensure the highest levels are maintained.Once the scan data is available in Rhino 3D, the GSS/DJA team can generate sections, plans and 3D models using the point cloud as control.
For stability work, we typically produce a faired model through the vessel – supplying a lightweight CAD model showing the critical structures of the vessel. Internal spaces can be modelled for fit out specialists and architectsto be able to plan internal layouts. Revised steelwork for areas such as bilge keels or superstructures can be designed using the base model and checked for fit against the pointcloud. Even data such as propeller diameters can be pulled from the scan data model, useful when the original is back in the water !
If you would like any further information on the use of the LS880 scanner for marine projects or if you have any questions then please contact either Roger Davies on 01686 412787 or e-mail roger.davies@geo-spatial.co.uk or Deri Jones on 0870 7620089 or via e-mail at info@djaweb.co.uk .