SeaVision Marine Services LLC: Underwater Inspection in Lieu of Drydocking

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LYYN1 “In order to better operate in the murky waters we often encounter, we are also ulizing a LYYN T38™ Visual Enhancement Tool which helps to ’cut through’ turbid waters in order to improve visibility.“ Jeffrey Z. Snyder, President of SeaVision Marine Services.

At SeaVision Marine Services LLC, we perform a variety of underwater investigations, such as hydrographic surveys, sidescan sonar surveys, marine magnetometer surveys, remote-operated vehicle investigations, and bottom sampling, in order to inspect places and things that are inaccessible to, or imperceptible by, divers.

Drawing upon nearly ten years of experience in marine operations to support diving and salvage operations, underwater surveys, and engineering design and construction projects, SeaVision can provide these services with value-added management solutions that help waterfront and marine clients to better manage their resources.

When a hull inspection is required – such as the two inspections of the outer hull of all sea-going vessels required every five years by the American Bureau of Shipping (ABS) and the US Coast Guard (USCG) – the solution is normally an expensive dry-dock trip. One of these two inspections can be carried out underwater while the vessel is afloat, a so-called Underwater Inspection in Lieu of Drydocking (UWILD) survey. Divers can often accomplish the task, but ROVs are ideal due to their thoroughness and detailed recordkeeping, not to mention the speed with which Inspections can be carried out, which is becoming important due to the increasing number of ships that need to be inspected.

Inspections with an ROV do not require tagouts intakes and outflows, nor are the safety regulations anywhere near as stringent as those when using divers. ROVs are not subject to physiological constraints – they can dive in water of any quality or temperature – to any depth required for hull inspection – for any length of me and in sea condtions that would preclude the use of divers.

However, divers have the advantage of being able to use tactile feedback to feel their way around a project site. Armed with knowledge of the surroundings prior to a dive, and communication with the surface during a dive, it is possible for divers to overcome poor visibility and use their hands, and other parts of their body, to navigate around a project site.

ROVs, on the other hand, can not provide tactile feedback to the operators. Even if armed with a manipulator arm, it may not be possible for an ROV to “turn around, face your rig, and take up your slack as you come back” in order to free an entangled umbilical. Instead, ROV operators rely on operational strategies and a growing suite of technologies to improve or supplement their spatial awareness in order to operate in environments with poor visibility.

“I recently completed two UWILD inspections on vessels operated by one of the major offshore support vessel companies in the Gulf of Mexico that are homeported in the brown waters of Port Fourchon. We used two inspection class ROVs from SeaBotix, in which the Integrated Control Console was equipped with LYYN™ image-enhancement boards. The LYYN™ visual enhancement was critical to the overall performance. Even after traveling thirty miles offshore we only had about 5 to 8 feet of visibility, but the LYYN™ unit really helped to clear up the imagery.

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The inspections were performed in open water, and the ROVs were subject to currents and hull-generated turbulence. The inspections required us to hover adjacent to azimuth thrusters on the vessels and perform 360-degree inspection of the thrusters, which posed significant fouling risks. The LYYN™ visual enhancement system helped to increase the stand-off distance to the thrusters (thus helping to minimize the risk of fouling) and also helped to improve the overall video quality so that the ABS and USCG inspectors could assess the condtion of the vessel.

The overall feedback from the inspectors, particularly regarding the improved video quality, has been very positive. The combination of fiber-opc video offered by these SeaBox systems, coupled with the integrated LYYN™ units, provides a nice video package for performing these inspections.

This will allow ship owners to make considerable cost savings.”

Jeffrey Z. Snyder, President SeaVision Marine Services LLC

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