Pond Inlet, Nunavut - 25 August 2014
Two Klein 3000 towed side scan sonars will be used to search for the two lost Franklin Expedition ships, including one from the Parks Canada survey vessel Investigator, and the other from the Arctic Research Foundation’s research vessel Martin Bergmann. This type of sonar is the principal remote-sensing tool in use with Parks Canada’s Underwater Archaeology Team that has been deployed in the search for Her Majesty’s Ship (HMS) Erebus and HMS Terror every year since 2008, systematically surveying in excess of 1,200 km2 in the process. The sonar sensor, housed in a tow body or towfish, trails behind the survey vessel close to the seafloor by means of a 200 metre armoured tow cable. The towfish are equipped with dual frequency transducers (110 kHz and 445 kHz), and can provide detailed acoustic maps of seafloor features including shipwreck structures and debris. A third Klein 3000 towed side scan sonar is available to be deployed from the Royal Canadian Navy’s Her Majesty’s Canadian Ship Kingston, with a 400 metre length of armoured tow cable to reach greater depths.
Parks Canada’s Underwater Archaeology Team will deploy their recently procured Iver3 autonomous underwater vehicle (AUV) for the first time in the search for the Franklin Expedition vessels. This third generation vehicle is equipped with a Klein UUV-3500 dual frequency side scan sonar. The two frequencies, 455 kHz and 900 kHz respectively, are optimized for expansive area survey and detailed imaging of identified seafloor targets. After determining its position and heading of the surface using GPS, sub surface navigation is possible with an inertial navigation system. Inertial navigation is essential for AUV operations in the Arctic where traditional magnetic compasses are unreliable due to the proximity of the Earth’s north magnetic pole. Communication with the vehicle is done with a wireless network, 2.4 GHz handheld radio remote control, and Iridium satellite uplink when travelling on the surface, and acoustic modem when submerged. The advantage of an AUV, as compared to a towed side scan sonar system, is that it offers a stable platform for sonar survey regardless of surface sea state, producing exceptional imagery in conditions that would thwart towed sonar operations. At 2.3 metres in length, this AUV can also be deployed manually by two people working from any vessel, including small boats, and can even be launched from shore. The Iver3 AUV can run for 10 to 12 hours, scanning a series of parallel survey lines in the same manner as a vessel towed sonar.
Parks Canada will deploy its recently acquired Saab Seaeye Falcon remotely operated vehicle (ROV). The ROV will be used to inspect or ‘ground-truth’ any targets that are identified in the course of the sonar survey. The Falcon is depth rated to 300 metres and is operated from the surface by means of a 300-metre long cable that provides the interface between the underwater vehicle and the surface control unit. Parks Canada’s vehicle is equipped with a new broadcast quality Kongsberg Oe-504 HD video camera and a Kongsberg 1171 sector scanning sonar system. The variable frequency 625 kHz to 800 kHz mini sonar head is specifically designed for use on inspection-class ROVs such as the Falcon, and has just recently been released by Kongsberg Mesotech Ltd. of Port Coquitlam, British Columbia. To accommodate the wide bandwidth necessary for real-time feed of high definition video and high resolution sonar data, Parks Canada’s ROV is furnished with fibre-optic telemetry. The Falcon is a highly capable underwater inspection tool, able to deploy a variety of sensors to assist in the documentation of submerged archaeological sites.
For a second straight year, Parks Canada’s Underwater Archaeology Team will be deploying its 10-metre aluminum survey vessel Investigator to Victoria Strait in support of the survey. Investigator was built to Parks Canada’s custom specifications by Kanter Marine of St. Thomas, Ontario, conceived as a dual remote-sensing survey vessel and dive tender. It is equipped with a stern-mounted A-frame to facilitate towing side scan sonar, while the transom free design above the waterline makes it easier to deploy and retrieve divers, ROVs and AUVs in and out of the water. Investigator will once again be staged from the Canadian Coast Guard Ship Sir Wilfrid Laurier, where it will be brought on board at the conclusion of each survey day by the ship’s large derrick crane.
This document is also available in Inuktitut at http://pm.gc.ca
