Tuesday, July 26, 2011


   Main photo: Wilhelm Schurmann (l) at Fishers factory with sonar tech Brian Awalt and side scan sonar. Bottom inset: German Type IX U-Boat similar to the discovered U-513, Top inset: U-Boat Captain Friedrich Guggenberger.
    The remains of the German submarine U-513 were recently discovered off the coast ofBrazil. The sub was sunk by bombs dropped from an American plane in July 1943. Only 7 of the 53 men on board survived the attack.  One survivor reported, “suddenly the bombs began to fall, one fell off the starboard side, and 3 fell right in front, then exploded...”.  Although Brazil had been technically neutral at the beginning of the war, it allowed the US to establish air bases from which it could launch attacks on submarines that were becoming a serious threat to allied shipping. As a result, Brazilian ships became a prime target for the U-boats. During the first half of 1942, German subs sank 13 Brazilian merchant vessels.  In August, the U-507 sank 5 Brazilian ships in 2 days killing more that 600 people. In all, 21 German and two Italian submarines were responsible for the sinking of 36 Brazilian merchant ships, causing 1,691 drownings and 1,079 other casualties. The sinkings were a major reason the Brazilian government ultimately declared war against the Axis.
    Researchers from Kat Schurmann Institute and Vale do Itajai University located the U-513 almost 68 years to the day after it sank. Using a combination of high tech equipment the 252 foot long submarine was discovered lying at a depth of 245 feet, 75 miles off the Brazilian state of Santa Catarina. Members of the Schurmann family, founders of the Kat Schurmann Institute, were actively involved in the search.  The family had procured a JW Fishers side scan system shortly after opening the institute, an organization that was devoted to fostering sustainability and preservation of the oceans and coastal habitats. The primary use for the sonar was to map the reef structures off the Brazilian coast. The hunt for the submarine started out as a hobby for family patriach Wilfredo when he was told the story of the sub’s demise by a fellow mariner while sailing the Caribbean.  Over the next eight years he spent many hours gathering information. He studied official accounts of the sinking, read survivors stories, talked to submarine officers in the Brazilian Navy, and even acquired a book titled “The U-Boat Commanders Handbook”. But one of the most useful sources of information proved to be local fisherman.  They told him about the “rippers”, obstructions on the ocean floor that would grab fishing nets and tear them up. Wilfredo was provided with the coordinates of some of these rippers. Combining pieces of information gleaned from historical accounts along with the position coordinates, the researchers were able to determine the most probable locations that would hold their prize.  At every opportunity a group from the institute, includingSchurmann’s sons, would take the side scan out and survey the underwater obstructions. The youngest son, Wilhelm,  had attended a training course at  Fishers factory in Massachusetts and was well versed on the operation of the side scan and use of the SONAR VIEW software.  On July 14, 2011 their hard work paid off and the side scan produced definative images of the remains of a pressure hull on the ocean bottom.  The final resting place of the U-513 was had been uncovered.
    Interestingly, the submarine was captained by Friedrich Guggenberger, who was one of the seven survivors of the sinking.  The captain had gained notoriety in the submarine corps while commanding another U-boat in 1941. He torpedoed the aircraft carrier HMS Ark Royal, which despite the British Navy’s efforts to tow it to port, sank the next day. After the war, the German Navy was reestablished and Guggenberger joined the service again. In the 1950s he travelled to US and studied at the Newport War College in Rhode Island.  He eventually rose to the rank of admiral in the German Federal Navy and went on to become Deputy Chief of Staff in the NATO command Allied Forces Northern Europe. 
    For more information on the side scan sonar or any of Fishers underwater search systems go to www.jwfishers.com.  For more information on the Schurmann family or Kat Schurmann Institute go to www.schurmann.com.br.  For more information on Vale do Itajai University go to www.univali.br.

Why use side scan sonar?  How does it work?

  Side scan sonars are one of the most sought after and effective tools for underwater search.  The reason; they can search large areas quickly and "see" what's on the bottom regardless of water clarity.  A side scan finds things by sending out a sonar beam which sweeps over the bottom, reflects off any object laying on the bottom, and returns to the towfish.  The sonar beam is tramsmitted and recived by transducers mounted on each side of the towfish.  The received signal is sent through the tow cable to a topside processor box.  After the sonar data is processed, it is sent to the laptop computer for display.  The displayed image is a highly detailed two dimensional picture of the ocean, lake, or river bottom, and any objects lying there.
   Side scans with low frequency transducers have excellent long range capability, but lower resolution.  Side scans with high frequency transducers have high resolution, but shorter range capability. JW Fishers offers three side scan systems; the SSS-100K with a maximum scan range up to 600 meters per side for large search areas, the SSS-600K with a max scan range of 75 meters but high resolution to locate small, soft targets like drowning victims, and the dual frequency SSS-100K/600K which combines the best features of both high and low frequency in one system.  
To receive a technical data sheet on side scan sonar or any of Fishers underwater search systems go to www.jwfishers.com or email to info@jwfishers.com. 

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