Raytheon Company Introduces A Dual-Axis Doppler Speed Log
For increased safety of navigation, Raytheon Company's Submarine Signal Division has introduced a dual-axis doppler speed log that uses bottom reflected sound to provide continuous and simultaneous display of speed along and across a ship's course.
The new system is already on order for six ships.
Manufactured by the division's Maritime Systems Department, Portsmouth, R.I., the Raytheon doppler sonar navigator (model DSN-400) tracks the bottom to depths of 1,000 feet, using acoustic beams directed ahead, astern, and to each side of the vessel.
In water depths over 1,000 feet, the system automatically shifts from bottom-tracking to watermass-tracking. The calculations of speed and distance run along and across course are based on differences in frequency between the transmitted signals and their return echoes caused by the motion of the ship. Depth indication to 1,000 feet is also a standard feature of the DSN-400.
The DSN-400 speed log is of particular value for piloting in shallow water, mooring, and approaching a berth. At depths less than 250 feet and speeds less than 10 knots, it indicates speed in hundredths of a knot, with display accuracy to within 0.02 to 0.04 knot. For bottom-tracking beyond 250 feet at any speed, display is in tenths of a knot, accurate to 0.1 knot.
In either "mooring" or "normal" modes of bottom-tracking, the system's indication of distance run is correct to within one-half of 1 percent of true distance covered over the bottom.
Water depth can be displayed in meters, feet, or fathoms, with an accuracy of plus or minus 1 percent of indicated depth. An adjustable shallow-water depth alarm warns when depth is less than a preset value.
DSN-400 data is processed for digital display on an easily read 14-inch by 18-inch bridge display/ control unit and for input to radars and other shipboard electronic equipment. Weatherproof digital and analog repeater displays are also manufactured for use in exposed locations.
The system has been successfully tested aboard a large tanker and a high-speed ro/ro trailership for extended periods of both bottom- and watermass-tracking in the North and South Atlantic Oceans, the Persian Gulf, and Mediterranean Sea.
Additional information on the DSN-400 may be obtained from Robert A. Sleiertin, Raytheon Maritime Systems, Box 860, Portsmouth, R.I. 02871.
Other stories from April 15, 1977 issue
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- Zapper, Inc. Applies For Title XI To Build $9-Million Barge Carrier page: 6
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- Hyundai Mipo Commissions Two Additional Graving Docks For Large Vessel Repairs page: 25
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- Toutant And LaGrange Named Vice Presidents At Jeffboat, Inc. page: 35
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- Number Of Vessels Classed By ABS Increased In 1976 page: 40
- Pacific Towboat Names Four To Executive Posts page: 41
- Santa Fe Affiliate Receives $40-Million Saudi Arabian Contract page: 43
- Shipbuilders Council Elects New Board page: 43
- Astilleros Espanoles Names Wesley Wheeler Exclusive U.S.A. Rep page: 44
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- Henschel Corp. Offers Literature On New Digital Shaft RPM Indicators page: 46
- Dillingham Ship Repair Names Charles Carter And Cliff Pritchard page: 46
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- Schedule Announced For ASNE Day May 5-6 page: 50
- New Barge Company Formed To Serve Alaska page: 51
- Gulf Mississippi Marine Signs For Three Vessels From George Engine page: 52
- NSF Certifies Demco Aeration Type Packaged Sewage Treatment page: 52
- ABS Elects Eleven New Members —Five New Managers page: 54
- R.L. Fagan Rejoins Stanwick Corporation page: 54
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- K.E. Sheehan Elected Vice President Of ABS page: 56
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