Saving Time and Money in Design, Manufacturing & Updating Marine Vessels
3D long-range laser scanning provides modern marine professionals an extremely versatile tool for precisely documenting, analyzing, and testing structures, electronics, engines and turbines, navigation systems, electrical systems, hull fluid dynamics, and even nuclear systems elements.
The underlying complexity of the marine world is enormous, entailing environmental concerns, human safety, and even multi-faceted physical elements such as building material properties, water and wind dynamics, and navigational currents. Marine vessels and offshore structures are some of the most complex mobile structures in the world, and encompass the fields of transportation, merchant markets, and the military, as well as underwater exploration, offshore drilling platforms, and high-speed and pleasure crafts.
Many marine vessels and platforms in service today do not have digital documentation or CAD models, so when they are constructed or due for any kind of repair work, updating, or refurbishing, the process is hit-or-miss as to whether the required parts will fit together and function correctly. The inherent inaccuracy of the physical vessel’s dimensions when compared to its existing 2D plans means that there are always mismatches between design data and reality. The actual as-built shape of vessels, from the hull to the layout of internal features such as piping, does not accurately reflect design prints. Long-range laser scanning’s true-to-life modeling results offer naval architects and marine engineers spot-on data of their vessels and structures to ensure that they are built, updated, and repaired correctly and safely the first time, saving both time and money.
According to Giles Gaskell, Business Development Manager of GKS Marine Services, “One of the most promising new technologies for solving complex problems in the marine engineering and architecture fields is long-range 3D laser scanning. In the last decade laser scanning technology has advanced to increase the range and accuracy of the scanners. We can now capture marine-sized structures to an accuracy equal to their manufacturing tolerances. Also, software applications that develop 3D models of plans such as piping and valves by recognizing the components that make up the system now exist to cut down the scanning and modeling time dramatically.”
3D long-range laser scanning provides modern marine professionals an extremely versatile tool for precisely documenting, analyzing, and testing structures, electronics, engines and turbines, navigation systems, electrical systems, hull fluid dynamics, and even nuclear systems elements.
• What is long-range 3D scanning?
Long-range scanning for marine applications is a ground-based technique for collecting high-density 3D data to create digital models of complex entities such as seagoing vessels, shipyards, offshore platforms, engine rooms, hull models, and other big structures and locations, both inside and out. Using the highly accurate 3D scan data generated with long-range laser scanning, engineers and designers can create CAD models of actual site conditions by processing the scan data into universally usable CAD models. GKS Marine has performed many long-range marine scanning projects, from reverse engineering ship hulls to documenting engine rooms and calculating volumes of fuel tanks, to scanning and modeling vintage vessels for hobbyists.
3D scanning of objects are virtually unlimited in size because the size of the specimen being scanned is not limited to the directional travel of a machine, or the reach of an arm. Long-range scanners functions in virtually any environment including broad daylight, the dark of night, indoors, and outdoors. Grayscale values are applied to the 3D coordinates which gives the data the appearance of a black and white photograph, or scans can be done in color, where each measured coordinate is also assigned an RGB color value.
Laser scanning technology is timesaving, clocking in at 100 times faster than conventional scanners, collecting 8 megapixels of data in less than one minute, so even the largest scan scenario is time-efficient. Non-contact laser scanning means that no detail is omitted or disturbed. New analytical software for Computational Fluid Dynamics (CFD) can take the scan data gathered by GKS Marine Services and use mathematical formulas to study and analyze water flow problems, leading to improved hull and structure architecture, fuel efficiency, power transfer, craft stability, and safety for construction crews as well.
• Applications of Long-Range Marine Scanning
Hull Surface Modeling
Many boats and seagoing vessels were built before CAD computer models were common, so no 3D model exists of their structures. When it comes time to repair, test, or update a hull, shipbuilders are left without accurate dimensional data. Boat hull designs involve complex free-form geometric shapes and are therefore very difficult to measure and model with traditional measurement methods. GKS Marine Services has scanned the entire hull surface on many large marine projects. The scan data allowed them to create precise 3D models that can be used by boat designers, boat owners, and naval architects for design, simulation, and inspection purposes.
Hull modeling to aid construction
The first thing to be built on a boat is the hull skeleton. Most of the time it is not exactly the same as the plan drawings. In order to fit all the parts and equipment to the hull, as-built data must be used and it must be very accurate. Long-range laser scanning of the inside and the outside of the hull structure provides scan data in progress at every stage to high accuracies, ensuring the fit of decking, cabin areas, propulsion systems, electrical systems, as well as design features on the bow and stern. Assemblies fit correctly so time and money are saved in building and retrofitting projects.
Marine simulations, such as stability testing and water flow analysis
3D scan data can also be used for marine simulations and tests. Laser scanning provides the high resolution data very quickly, so digital models can be made and used to create 3D virtual spaces and simulations at any stage of the construction process or afterwards on an in-service vessel. Simulations can be run to test the stability, which of course, is a critical factor in boat design. Being able to run tests on the precise 3D measurements saves time and ensures craft safety.
Installing a perfect-fitting new hull feature
GKS Marine Services modeled the hull of a Coast Guard cutter to provide accurate data from which to install a transom platform and stern flap. A stern flap is an extension of the hull bottom surface which extends behind the transom and is designed to reduce propulsion power requirements and emissions, improve fuel efficiency, speed and range of travel.
Engineers used the ship’s scan data to create an accurate CAD model. The model allowed the engineers to perform simulations to determine the optimum location and geometric shape for the stern flap. The savings realized in fuel economy alone quickly recouped the cost of the scan and the modifications.
• Retrofitting, upgrading, replacing, and repairing equipment and systems
With the constant strains imposed on vessels and ocean platforms by the forces of water, keeping things in “ship shape” is imperative to seaworthiness and safety. A major factor that prevents implementation of design upgrades is a lack of as-built dimensional data. Continuous upgrades, repairs, and replacement of many systems can be efficiently accomplished when up-to-date CAD data of the systems’ configurations exist.
Special software applications are available to develop 3D models of plans such as piping, wiring, and valves by recognizing the components that make up the systems. These advanced software packages greatly expedite the scanning and modeling process.
If a ship is out at sea when a repair is needed, having accurate system data to share can help a shore-based engineer in advising sailors how to best go about fixing the problem.
Sometimes extremely tight tolerances must be maintained to insure the ideal mating of diverse parts. In such cases, GKS Marine Services uses a laser tracker measuring device in conjunction with the laser scanner to align large-scale scans very precisely.
• Offshore platform construction and modification
Building and servicing offshore platforms are inherently dangerous activities. Harsh weather conditions and hazardous surroundings demand extremely efficient and safe procedures to perform these jobs. Luckily, much of the construction can be done with modules built on land and then assembled on-site. This type of construction has its own challenges, however, mainly ensuring that modules fit together correctly and securely. Incomplete or obsolete offshore facility documentation plagues offshore engineers who are tasked with constructing and modifying the platforms.
Offshore oil production facilities provide tremendous dimensional control challenges throughput their entire lifecycle. Frequent modifications can be viewed in the design to check for potential collisions and necessary reworks. The lifecycle of a facility can be documented through repeat scans detailing any changes occurring while maintaining an accurate record of the current condition.
Offshore construction can also be facilitated by scanning, using the scans to inspect the work at various intervals. That insures that plans are accurately executed and uncovers design flaws before they become costly and time consuming. Long-range scanning is invaluable in conditions that are less than optimal for manual measurements such as can occur on huge oil rigs.
During construction, tolerances must be closely managed between topside structures and underwater ones, which can be difficult because they are often built in different facilities. Building modifications, upgrades, add-ons, or reconstruction of the assembly at a different location can now be accomplished against an as-built condition that is completely documented in 3D. This greatly speeds up the project and, most importantly, provides greater reliability that the project will be completed correctly with no surprises when materials and prefabricated components arrive on the job site.
Laser scanning can validate the entire jobsite geometry including locating tie-ins and anchor bolt locations; it can verify footing dimensions and positions. The technology can also be used to provide measurements on land prior to subsea installation which will, when combined with acoustically acquired position data about the installation point, eliminate the need for much deepwater measurement while providing an accurate first-time fit. In the case of damage from a storm, the structure must be rapidly documented to aid in repair or decommissioning.
Oil platforms and rigs contain mazes of pipe work. Documenting existing setups and planning for alterations can be facilitated by accurate 3D data gathered through long-range 3D laser scanning. Long-range scanning provides a fast and relatively inexpensive method to produce accurate drawings which are often required in order to comply with the latest OSHA safety regulations.
• Restoring or modeling a vintage or damaged boat
The lack of 3D CAD data is also a major roadblock to any major restoration of a vintage or damaged boat. However, this lack of 3D data can be easily remedied. GKS Marine Services has laser scanned many vintage boats, some which were damaged as well, for collectors who wanted to restore their prized possessions to mint condition. The free-form, complex shapes of the hulls are difficult if not impossible to recreate by any other method because of the irregular geometry and small details. Of course, non-contact laser scanning does not damage the article being scanned, so the boat is not be harmed in the scanning process.
With laser scanning, the as-built, 3D digital data is collected quickly and accurately. Without non-contact 3D laser scanning, capturing enough data coordinates to accurately define the boat’s shapes is a very labor-intensive and time-consuming job, and results in a much less complete data set. The scan data enables data modelers to create CAD models of the boats “as-is” for exact replication—or from the CAD model, a boat designer can make desired modifications or digital “repairs” to faithfully replicate the original or incorporate updates. Another use for the 3D scan data is scaling down the size of the watercraft to make smaller models with exacting details, popular with boat hobbyists.
• Environmental upgrades to increase efficiency of engine and structure
Today’s push to conserve energy and reduce dependence on foreign oil is another reason long-range laser scanning technologies are gaining momentum in the marine marketplace. Large vessels and structures have, in the past, been problematic to measure and to monitor their efficiencies and fuel consumption accurately. With this advanced measurement method, however, the size and scale of a structure, or the conditions in which it exists do not pose obstacles to obtaining accurate 3D models.
Computational Fluid Dynamics (CFD) software can use the scan data gathered by GKS together with mathematical formulas to study and analyze water flow problems, leading to improved hull and structure architecture, fuel efficiency, power transfer, craft stability, and safety.
Marine simulations and water flow analysis
Laser scanning provides high resolution data quickly so digital models can be created for testing new features or to help determine why a vessel is not functioning as expected. Running simulation tests on the precise 3D measurements saves time and ensures craft safety.
GKS Marine Services performed a scan on a military ship that was having difficulty controlling the water intake of its ballast tanks. For some unknown reason, the tanks were not taking on water as they should have. This was adversely effecting the ship’s fuel consumption and hydrodynamics. GKS engineers were able to scan the tanks’ interiors and determine wear differences on the inside walls, indicating where water levels were irregular.
It turned out that the tanks were not filling to capacity because the interior shape was creating very large air bubbles as the water flowed in, preventing them from providing the ballast the ship needed to perform optimally. With this knowledge, the tanks were redesigned with better hydrodynamic shapes to correct the water inflow. Better hydrodynamics translated into better fuel efficiency and cost savings.
The future of 3D laser scanning in marine applications
The ubiquitous problem of nonexistent CAD models of marine vessels and offshore platforms is a significant lapse which affects non only the ability to construct, repair, retrofit, remodel, and repurpose marine structures, but also has serious safety ramifications for marine workers and passengers alike. The fact that extant 2D plans are inaccurate when compared to the 3D reality is also a concern.
Long-range laser scanning is an innovative aid to naval architects and marine engineers in their wide-reaching work of redesigning, repairing, repurposing, and restoring marine vessels, structures, and systems to be up-to-date, safe, and structurally sound.
• About GKS Marine Services
GKS Marine Services, a part of GKS Global Services, has been a leading provider of #D laser scanning, for over 25 years, with specialized experience in marine applications. For information, 1-888-457-7727 or visit: www.gksmarine3d.com.