MakaiLay Movies

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For the first time, cable engineers can "see below" to visualize how dynamic events affects placement of their cable onto the seabed. Such knowledge improves their ability to reliably lay cables with high degree of placement accuracy and slack/tension control. The following movie clips show different aspects of MakaiLay operations while operating in simulation mode. The red object represents the vessel, the orange and green lines represent snapshots of the cable shape every 5 minutes (different colors representing various cable types).
This movie shows a 3-D view of a time-stepped series of cable shapes, at 2-minute intervals, for a typical cable installation with a single ship altercourse followed by a change in the cable type (e.g., lightweight protected to single armor). The ship moves toward the right along the ship path, angled due to the perspective. To the left while laying the lightweight cable, the solutions are nearly steady-state straight lines. Toward the right, a heavier cable is installed as the ship negotiates an altercourse (vertical line). The cable shape then becomes dynamic (due to the differences in sinking rate of the cables) and the cable touchdown slack varies from the steady-state solution.
MakaiLay uses a 3D, finite segment, time-stepping model to accurately calculate the cable shape and associated inline bodies as they descend through the water column. This movie shows two large altercourses (representiant a total change in course of 165°), a transition from a lightweight protected to a single armor cable type and the deployment of several heavy repeaters. The weight of the inline bodies result in touchdown of the bodies on the seafloor before the cable between the bodies and the generation of slack before and after touchdown. Towards the end of the movie, one can see the transient of the cable in the water column as the vessel speed decreases.
A plan view of the simulation of laying a cable and repeater while negotiating an altercourse. The ship maneuvers outside the RPL path with two additional altercourses in order to place the repeater and cable more closely along the cable path and away from the seamount to the right. The dashed line shows the touchdown if the ship follows the RPL path. At the illustrated moment, the ship is at the top of the illustration while the touch-down is just beyond the repeater at the bottom,16 km behind the ship. Water depth is 4000 meters and the ship speed is 5 knots.
This movie shows the first part of the installation: a repeater is deployed and is malfunctioning as it nears the touchdown point, so it must be retrieved. Initially, the vessel stops while cable is still being paid out at reduced rates in order to maintain cable bottom slack at the 3.5% target value. In order to decrease the time for the retrieval operation, the vessel backs up. It moves back increasing its speed from 0 to 1 m/s while cable is paid out, at ever decreasing speeds. Throughout this operation, average bottom slack is kept at 3.5%. Finally, both vessel and cable are being retrieved at 2 knots maintaining small values of bottom tension (< 350 kg).
A continuation of the retrieval process is shown in this movie. The vessel is moving from left to right at 2 knots as cable is retrieved. The repeater is lifted off the bottom, and as the repeater nears the surface, the vessel stops while additional cable is retrieved to always maintain a residual tension on the bottom. Cable retrieval is finally stopped, and cable bottom tension is kept at 400 kg while the vessel maintains position.
Once the repeater is repaired, the installation proceeds as shown in this movie. The vessel speeds up to 3 knots while the cable payout is slowly increased. The cable on the bottom goes from a tensioned condition (400 kg) to a slack condition over a distance of 1 km. After this, payout is controlled to maintain the 3.5% target value of bottom slack. Almost four hours after re-starting the lay, the repeater is safely on the seafloor.
Makai has spent a tremendous amount of R&D effort into testing, validating and expanding their dynamic, 3D cable model for other applications, such as the oil and gas industry, the deployment of seafloor arrays, and the deployment of surveillance arrays. This movie shows a UUV deploying and array with multiple in-line sensors. Note the strong cross currents forcing the cable to one side of the route. MakaiLay can predict accurately the location of the sensors on the seafloor.
This movie shows the deployment of a seismic array near an oil rig. Sensors are spaced every 50 m along the cable (red spots) and water depth is 450 m. The MakaiLay Seismic software can incorporate real-time measurements of the currents and position data provided by transponders on the cable in order to improve the accuracy at which sensors are installed on the seabed. Note that while the vessel changes course continuously at the surface in order to compensate for the changing currents, the cable on the seabed follows very close the desired route and sensors land close to their targets (targets indicated by the vertical lines).
This movie shows the installation of a seismic array with geophones (Z-pods) spaced every 25 meters along an almost neutrally buoyant rope in waters 300 m deep. As the sensors approach the seabed, they sink faster than the rope and generate additional slack on the seabed affecting the final separation between consecutive sensors. Later in the movie, we show how by controlling the cable payout rate, we can apply a slight tension on the seabed to eliminate any seabed slack and assure that the sensor separation remains at a constant 25 m as desired.
This video shows how MakaiLay Seismic can be used to safely and rapidly retrieve submarine arrays from the seabed. Historically, arrays have been retrieved with high tensions in order to prevent the array from looping back on itself or fouling with seafloor obstacles. However, high tensions have resulted in damage to the sensors and the array. Today, arrays are being retrieved at conservative speeds to minimize damage to the cable. Slower speeds result in longer retrieval operations and an increase in costs. MakaiLay Seismic provides cable engineers with real-time feedback of the cable touchdown and tension on the seafloor and on the effect of cross currents acting on the array. Therefore, the tension of the cable can be better controlled during the retrieval process maximizing cost savings while minimizing array damage. Note: this video includes narration .