Submersible Vehicle Systems DesignUnmanned underwater vehicles provide several advantages for conducting hazardous activities submerged in water. The vehicles are called by different names - remotely operated vehicles (ROVs), submersible devices, or remote controlled submarines. The key activities for the devices are well elucidated. They function in hazardous environments and execute activities that would be difficult for humans.
The first submersible vehicle was developed in the 1960’s for the US Navy - conduct underwater rescue and salvage operations. The other industries have leveraged the potential of the UUVs for various activities. Oil & Gas sector utilized UUVs to enhance the development of offshore oil fields. By the 1980’s, UUVs were able to function at depths which were below commercial diver limits. The fall in oil prices and recession across the globe led to stagnancy in UUV development in the mid 1980s, but ever since, the UUVs have been developing rapidly.
At present, UUVs are used in various applications – identifying ship wrecks, mapping the sea floor, detecting objects, securing harbors, locating sea mines. Since more than 50% of the oceans are under great depths, UUVs are being developed to search the ocean’s depth. However, the development of these UUVs challenges the design specifications for the hardware.
The hull design can be looked at from various perspectives. Factors that must be considered while designing are:
- Pressure and/or depth required
- Operating temperature ranges
- Structural integrity for additions and tapings
- Impact conditions
- Water permeability
- Visual appeal and aesthetics
- Restrictions for future additions
- Size requirements
- Corrosion and chemical resistance
The first factor to be looked at while designing is the shape of the hull. A cylindrical hull is preferred – appropriate geometry for both pressure and dynamic factor. Since the water pressure increases with depth, the hull thickness must increase with an increase in the depth. Any design function must take into account static and dynamic diving principles.