Posted on 10.12.2010 - 10:00 EST in ROV NEWS by Rons_ROV_Links
In April, 1940 during the German invasion Weserubung the ship MV Seattle came under crossfire between the German cruiser Karlsruhe and the Norwegian coastal fortress Odderoya. The Seattle was on its way to Kristiansand when the Karlsruhe began firing on the Seattle with it's 150mm cannons. Within a short few minutes the Seattle caught fire. The crew abandoned ship and over the next few days the Seattle continued to burn and drift through the fjord. Eventually the Seattle sunk in the deep at Dvergsnestangen where it is located now.
Since the Seattle's discovery in 1988 the wreck has become a popular dive site. The wreck lies on a slope with the stern at approximately 24 meters depth and the bow close to 72 meters. Wrecking diving can be dangerous and especially at these depths. Recently a pair of divers were reported missing after diving on the Seattle. The divers had a dive plan consisting of a dive to 48 meters on 23% nitrox as main gas and two stage bottles with one at 48% nitrox and the other 70% nitrox for decompression. Their plan was to dive the outside of the wreck and take a shallow ascent through the cargo room. The surface dive buddies reported the missing divers 30 minutes after their scheduled return.
Robert Sorheim Olsen of Neptun Marine Consulting was asked by the Norwegian Police to aid in searching the internal structure of the Seattle for the missing divers. After arriving in Kristiansand Robert created a plan for the search. Using plans of the Seattle and the knowledge of a dive guide with more than 100 dives on the Seattle a methodical search pattern from stern to bow approach was determined the best approach.
Leading up to the internal search the fire department rescue divers, coast guard and military had searched the area surrounding the wreck. Additionally Norwegian based company Seabed Services spent five days searching the outside using a Buster MK III and side scan sonar.
The conditions were not favorable during the search with strong current flow heading out to the North Sea. Robert managed to get the LBV deployed and begin the planned search pattern from stern to bow. The powerful thrusters, 4-axis maneuverability and low drag tether enabled Robert to successfully penetrate the wreck. Fitted with a Tritech Micron scanning sonar and utilizing the ship plans navigation through the wreck was easily managed. There were trying times as the tether would entangle on the wreck, but the LBV fitted with a grabber was always able to free itself. At one stage parts of the cargo room collapsed, but fortunately Robert was able to maneuver the LBV and avoid getting stuck.
After two long days operating and covering three levels with penetrations up to 30 meters Robert was able to confirm that the divers were not within the wreck. The combination of diver knowledge, plans, high-resolution video and scanning sonar imagery ensured that no area was left unsearched. Robert's competent operator skills, patience and a capable ROV system were critical to the search and as a result the wreck was successfully cleared without putting further divers in harm's way.