Abstract: The output of an auxiliary sensor, such as a magnetometer or metal detector, is recorded along side a sonar trace record, such as from a side scan sonar or sonar sub-bottom profiler, using the same recorder mechanism. In one embodiment, the added information permits correlation on the same chart between sonar generated impressions and local magnetic field disturbances such as produced by magnetically susceptible objects located on or below the seabed. The sonar record is typically provided as a series of adjacent scan lines, intensity modulated in accordance with the intensity of a received sonar echo. A conversion circuit transforms the output of the auxiliary sensor into a format consistent with the sonar scan trace whereby the sensor output is directly reproduced as a part of the sonar trace record, typically at a peripheral edge portion where the sonar image is absent.

Abstract: This disclosure is concerned with adapting helical electrode-grounding electrode signal recording apparatus, normally suitable for wet paper signal recording, alternatively to operate with dry coated recording paper of the type previously recordable upon by point stylii and the like, through a combination of novel signal feeding circuits, electrode shaping, paper orientation and electrode pressure.

Abstract: This disclosure deals with novel underwater vehicle towing and recovery apparatus, as for recovering sonar or other underwater apparatus in the event of cable severance and for preventing the sinking of apparatus on the stoppage of towing, through the combination of water-foil depressor mechanisms and buoyant recovery chambers provided with signalling apparatus.

Abstract: This invention provides two dramatic improvements in the state of the art of side scan sonar systems and the like, bringing out the fine details of the sonar signals to enhance the texture of the sonar charts and to improve the quality and interpretability of the sonar records, while additionally bringing the sonar signals into the dynamic range of the recording medium in such a way that the tuning of the sonar instrument is greatly simplified and, in many situations, may be run continuously with no operator's adjustment of the instrument controls. These ends are attained through a novel compressed-signal absolute value smoothing and derivative processing, with dynamic range matching to the recording medium.