ISE’s Aurora Active Towfish was towed for the first time from existing route survey equipment belonging to the Canadian Navy aboard a Maritime Coastal Defense Vessel (MCDV) off the coast of Vancouver Island.
Built in the 90’s for coastal defense, the Canadian Navy’s MCDVs were equipped with Route Survey System (RSS) payloads consisting of a high performance multibeam sonar built into a variable depth actively controlled towfish, and a shipboard handling system.
However, over the years, the operation of the variable depth active towfish has become problematic. As the Navy’s successful Interim Remote Minehunting and Disposal System (IRMDS) currently incorporates ISE’s Aurora variable depth towfish, there was an opportunity to integrate the Aurora towfish with the existing RSS
handling device and demonstrate the resulting towing performance from an MCDV.
The integration of Aurora with the RSS handling system was extremely straightforward, requiring minimal modifications to the towfish docking mechanism, as shown above. This towing trial is part of the Route Survey System Life Extension (RSSLE) project’s definition phase. During the three days of towing, over 20 hours of towing was completed in conditions including 25 to 30 knot winds and sea states up to 4.
The Aurora towfish provided very stable performance during unfamiliar handling maneuvers, launch and recovery, and operations with both faired and un-faired cabling at a variety of cable scopes, speeds, and depths. This indicates the Aurora can meet the Navy’s towing requirements for the next generation of high performance mine hunting sonars.
The Aurora Towfish is owned by Defense Research and Development Canada (DRDC) Atlantic, and has been a part of a working relationship between DRDC and ISE for over 20 years. It is an integral part of the Canadian Navy’s IRMDS program.
ISE is extremely pleased to be a part of the RSSLE program and looks forward to future integration. Based in British Columbia, Canada, ISE has been involved in the design and development of autonomous and remotely operated underwater vehicles and robotics for over 30 years. Working with North American and International customers, ISE’s experience is represented by over 210 underwater vehicles, 26 of which are AUVs, built and delivered to clients in 20 countries. The Aurora Towfish is controlled by an ISE common controller.
The 1,000lb device, thought to be German and dropped in 1942, was washed ashore at Felixstowe, a week ago, and hundreds of homes were evacuated.
Bomb disposal experts attached the device to a floating frame to tow it two miles out to sea to destroy it. But strong tides dislodged the bomb and Royal Navy divers have spent six days trying to relocate it.
An exclusion zone has been imposed to protect boats.
A Royal Navy spokesman Lt Cdr Mark Hankey said the bomb had been "misplaced" when one of its lift straps broke.
"It was slight technical malfunction, but it had the effect of disconnecting the marker buoy," he said.
He added: "If the operation had gone according to plan, it would have been dealt with by now, but sadly it didn't. We are throwing as many resources at it as we can."
He said water visibility was "horrific" and it was difficult for divers to operate in the fast current.
The unit is using an unmanned computer-operated submarine called Remus to try to locate the device.
Lt Cdr Hankey said: "I am confident it will be found. Our chances of finding it have been significantly enhanced by the use of the unmanned underwater vehicle.
"Once it as been located, a charge will be attached to it and it will be blown up in a controlled manner when everyone is at a safe distance."
A Navy spokesman said he understood the depth of water was not sufficient for a minehunter vessel with a camera to operate.
It had also not been possible to track the bomb with a GPS receiver because it would not work underwater.
The bomb was discovered a week ago by a workman who accidentally scooped it up in his digger bucket while working on new £10 million sea defences.
Lt Cdr Hankey said: "It is important to stress that the bomb is a lot safer than it was because it is now offshore."
The bomb is thought to be well away from shipping lanes used by vessels going in and out of Felixstowe, the biggest container port in Britain.
A local resident, Karen Sarrow, 35, of Felixstowe, said: "It is just a fiasco that they have managed to lose this enormous bomb. They should be really embarrassed. People have been saying that it is like something out of Dad's Army."
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