The Engineering Of Nova Ray® ROVs
Engineering The Future Of High Performance Submersible ROVs
What Makes The Nova Ray Different?
The Nova Ray is fundamentally different for several significant reasons:
Total Hydrodynamic Stability
The application of the arcuate wings, control surfaces, the neutral buoyancy, unique tow-point, and other proprietary patented design elements come together to create a unique underwater vehicle with incredible hydrodynamic stability unlike other ROVs. In the case of other ROVs, that faster they move through the water, the more unstable they become – not with the Nova Ray! In fact, the fast it moves through the water, the more stable it becomes, but it is also stable even at sub-knot speeds.
See our page on the arcuate wings for more information.
Most ROVs (either Torpedo Shape or Box Shape) when operating underwater need to be weighted to compensation for buoyancy and to have sufficient mass to be somewhat stable when towed. In large measure, their stability comes from the tow forces itself, but these also cause significant destabilizing effects. For each mission, the weight added or removed to the traditional ROVs are critical in improving control. Unfortunately, proper buoyancy is always a changes for many ROVs, but even with perfect buoyancy balance, the other factors still play a major roll in reducing their stability.
Nova Ray is designed to be neutrally buoyant to begin with, and with its arcuate wings eliminates the destabilizing forces that make other ROVs either difficult to control, or very limited. The proprietary design of the arcuate wing material is uniquely blended to achieve this for the specific models maximum operating depth.
Tether Pull / Lay
Different ROV manufacturers place the tether connection or attachment point at different places on the ROV frame. Some along the center axis, some on top forward, some centered on top. All such attachment points bring their own challenges. Along the center line induces “cork-screw” roll effects caused by the tether twisting in the water as tension is applied or relaxed.
The Nova Ray’s proprietary tow point overcomes most of these forces, along with its arcuate wing design deliver stability dampening automatically the tether oscillations and twisting that can cause instability.
Additionally, most ROVs have limited ability to pull their tether through the water, overcoming the drag caused by flow and current forces. The Nova Ray’s arcuate wings combined with onboard thrusters overcome the tether drag. This allows for substantially great mobility for the same tether length, and permits the use of much longer tethers as well.
The Nova Ray also does not have the problems of tether lay acting as a “sail” – it has the ability to easily pull its tether without the effects the destabilize and inhibit control on other ROVs.
These factors allow the Nova Ray to perform at substantially higher speeds through the water even at fully extended tether lengths.
Impact Resistance / Risk Reduction
Most ROVs are inherently fragile, and difficult (if not impossible) to repair at sea. Nova Rays are designed to be modular and easily repairable, with minimal down time (a Nova Ray could be completely rebuilt in a few hours).
A critical risk for most ROVs are collisions – with the vessel, the bottom, and hazards of one type or another (such as what they are supposed to be inspecting or working on). The Nova Ray design incorporates not only neutrally buoyant poly foam for its wings, but also for the landing/attachment skids. The wings and skids provide a substantial degree of impact resistance and shock absorption, limiting damage from impacts. Additionally, the machined metal and poly components provide for an exceptionally long useful lifespan of approximately 20+ years with proper maintenance and upgrades.
Continuous Operation / Duty Cycle
The Nova Ray is designed to be a continuous “work horse” ROV, capable of being kept in the water as long as needed. Its unique capability for carrying sensors & manipulators means that it can not only do large scale surveys but at the flick of the joystick move in for detailed inspection, eliminating the need for secondary devices. If a change in sensors is needed, the Nova Ray can be immediately adapted in the field with very little loss of productive time. Our clients have kept Nova Rays in the water for weeks on end. In fact, the Nova Ray has actually been tested for a full year continuously submerged and inactive – upon removing it from the water, it was fully functional with no wear.
Depth / Altitude Precision
Most ROVs (torpedo or box-shaped) suffer a fundamental deficiency – the inability to maintain a precise altitude over distance. Not only is angle or attitude instability their problem, but altitude fluctuations caused by tether drag, currents, and other forces result in scale problems with sonar and other data.
Because of the Nova Ray’s unique arcuate wing design, it has the ability to fly straight and level at a precise depth or more specifically altitude above the floor. This provides the most stable platform for data gathering, with not only higher usable resolution but also consistent scaling of sonar data. This also makes it perform for other types of data gathering as well, from magnetometers to LIDAR.