In today’s world, there is a constant threat of physical and economic harm from many sources using non-traditional and harder to detect methods. Below the waterline, there are a limited number of solutions for detection even though the problem is real and ongoing. For example, only a small fraction of vessels entering our ports are routinely inspected for contraband, and there will always be a need to inspect our military assets from dangers such as covertly attached limpet mines.
As the threats evolve and become more sophisticated, a new breed of ship hull inspection tool is required. The traditional and most common method still involves human divers. This presents obvious issues such as putting people in harm’s way, significant manpower needed at each inspection, high costs associated with each inspection, and large amounts of time in set-up, coordination and breakdown. Remotely-operated vehicles (ROVs) are a good solution for alleviating many of these issues.
SeaBotix, Inc. of San Diego, California has developed a highly unique, yet remarkably simple solution for thorough ship hull inspection. Already established at the industry leading MiniROV manufacturer, SeaBotix combined years of experience with cutting-edge technologies and developed the Little Benthic Crawler (LBC), a 5-axis ROV with an optional crawler skid and attractor system that allows it to affix to relatively flat objects of any solid material.
When conditions permit – or access demands – the LBC can operate as a traditional 4-axis ROV. Simple and intuitive to control, the operator can quickly survey a ship hull, anchor, or port. Under more challenging conditions, such as higher current or poor visibility, the LBC can quickly be converted to Crawler Mode. With the Crawler Skid attached, a unique flotation arrangement provides a ‘meta-centre’ point of gravity, allowing the vehicle to easily roll port or starboard. Once the LBC rolls and matches the angle of the hull, the attractor is energized, attaching the LBC to the ship hull.
The attractor is a compact but powerful vortex generator creating ~23kg (50ft/lbs) of force at 2.5cm (1”) from the surface of the hull. Once attached, the LBC becomes a vehicle rather than a helicopter, reducing the inspection site to a 2D space. The unprecedented stability allows the operator to navigate in more extreme conditions with greater precision, meaning sensors and tooling can be accurately positioned. The operator can drive directly to an area of interest and stop. Without any piloting required, they can then concentrate on the data being provided from the cameras, sonar, and other sensors. Once the area is cleared, the LBC can then drive to the next object of interest or in a set path to ensure total coverage of the hull. Traditional ROV operations require the operator to continuously pilot the ROV while simultaneously monitoring sensor data. Or, additional persons are required to evaluate the data.