Abstract: A relative speed of an object is determined by monitoring random reflective surfaces in water. The system includes a first and second transmitter-receiver pair for producing echo signals of a monitored region. The monitoring pair of transducers are preferably positioned along an axis of motion of the object such that sampled data from the first and second transmitter-receiver pair are substantially similar but shifted in time due to a separation of transducers. Echo signal data from the transducers are then used to generate a time difference correlation function that is used to determine a time difference between the first and second signals. Based on the time difference between the time-shifted echo signals, a speed of a vessel is determined.

Abstract: A transducer assembly for mounting to an interior surface of a hull includes a base for securing the assembly to the interior surface of the hull. A mounting member for mounting to the base is rotatably positionable relative to the base about a rotational axis. A transducer element is secured to the mounting member for generating soundwaves that travel in an acute angular direction relative to the rotational axis. Rotation of the mounting member relative to the base about the rotational axis changes the direction of travel of the soundwaves. A retaining device locks the mounting member in place relative to the base.

Abstract: An acoustic system and a method for repelling marine mammals from a region of water is disclosed. A plurality of acoustic transducers (10,12,14,16) are spatially dispersed beneath the surface of the water. The transducers (10,12,14,16) in sequence output high frequency acoustic signals into the water. The power of the acoustic signals starts at a low level and is gradually or incrementally increased to a high level which produces a signal beyond the threshold of pain of the mammals to be repelled. The mammals are therefore gradually repelled from the area without suffering permanent hearing loss.

Abstract: A marine speedometer for mounting to the exterior transom of a marine vessel includes a housing mounted to the transom flush with the bottom surface of the hull. A paddlewheel affixed to the housing has an outer periphery which extends no further than the bottom surface of the hull of the marine vessel. A portion of the housing adjacent to the bottom surface of the hull is shaped to direct a flow of water passing by the transom upwards into the paddlewheel to rotate the paddlewheel.

Abstract: A forward looking echosounder uses a non-scanning forward looking transducer inclined from the horizontal at a 45.degree. angle. The forward looking transducer produces a set of acoustic data signals indicative of echo signals received along the central axis of the sonic beam as produced by the transducer. Distance and depth coordinates are used in conjunction with vessel speed and pitch angle to determine where the source of the received echo is located relative to the moving vessel. This information is then displayed in a quasi-real time display format.

Abstract: A low cost phased array sonic transducer is described in which an array of transducer elements separated by spacers are held within a frame which applies a compressive force transverse the length of the elements.

Abstract: A marine sensor mounting mechanism having a tubular sleeve in the hull of a boat; valve means mounted for pivotal movement in the sleeve from an open position when a sensor is in place to a closed position when the sensor is removed.

Abstract: A through-hull speed sensor of the magnetized paddlewheel sensor type wherein a paddlewheel is rotatably supported in a cavity adjacent a magnetic sensing device which generates electrical pulses corresponding to paddlewheel speed as the wheel rotates when the vessel moves through the water. The sensor has improved low speed characteristics provided by a housing which extends the paddle wheel into the water below the hull. The bow of the housing provides a new leading edge, generating a smaller thickness boundary layer at the paddlewheel, so that the paddles project beyond the layer at low speeds. High speed performance is improved by having a high ratio of paddle fore-to-aft drag coefficient shape; keeping the periphery of the paddlwheel hub within, or flush with, the bottom of the cavity; a low paddle projection versus paddlewheel radius ratio; and by keeping the ratio of paddle cross-section versus available cavity cross-sectional space within an optimum range.

Abstract: Mechanism for mounting a marine instrument (I) on a boat having a mounting block (12) and a pair of brackets (10) spaced from each other on opposite sides of the block (12). There are pivots (20) for mounting each bracket on the block for pivotal movement about a common axis (22). The marine instrument (I) is between the brackets. A spring (44) biases the brackets (10) and into forceable engagement with each other. Mating latch means (52-78) on the block and the brackets respectively retain the instrument in a first operative position. The mating latch means are disengageable to permit the instrument to be pivoted to an inoperative position.

Abstract: A through-hull speed sensor of the magnetized paddlewheel sensor type wherein a paddlewheel is rotatably supported in a cavity adjacent a magnetic sensing device which generates electrical pulses corresponding to paddlewheel speed as the wheel rotates when the vessel moves through water. The sensor has improved low speed characteristics provided by a housing which extends the paddlewheel into the water below the hull. The bow of the housing provides a new leading edge, generating a smaller thickness boundary layer at the paddlewheel, so that the paddles project beyond the layer at low speeds. High speed performance is improved by having a high ratio of paddle fore-to-aft drag coefficient shape; keeping the periphery of the paddlewheel hub within, or flush with, the bottom of the cavity; a low paddle projection versus paddlewheel radius ratio; and by keeping the ratio of paddle cross-section versus available cavity cross-sectional space within an optimum range.

Abstract: An adjustable marine instrument mounting mechanism having a tube (2) for mounting a sensor (S) at one end, a base (14) which is attachable to a boat, and a housing (28) which pivots on the base and which mounts the tube and the instrument. Means (104) employed to latch the housing to the base in an operative non-pivoting position, and means (50), (52) and (72) are employed for latching the tube and instrument in both an elevated inoperative position and a lowered operative position.

Abstract: A marine sensor mounting mechanism is disclosed and comprises a mounting plate (2) securable to a boat, a two-branch bifurcated bracket (4) having one branch attached to the plate and a two-arm toggle link (6) having one arm pivotally attached to the plate and the second arm pivotally attached to the second branch of the bifurcated bracket. The arms of the link are paired for pivotal movement for a first open position when the sensor is in an inoperative position to a second closed position when the sensor is in an operative position.

Abstract: A modularized marine instrument sensing device is described wherein a paddlewheel assembly for providing an electromagnetic signal proportional to marine vessel speed is separably mountable on retaining members provided in a sensor housing. The sensor housing may house a Hall-effect device which converts the varying magnetic field from the paddlewheels to an electrical signal proportional to vessel speed. The sensor housing may also incorporate a piezoelectric transducer for providing a depth sounding and fish finding function. Optionally, the paddlewheel assembly may include a temperature sensing device, such as a thermistor, within a frame assembly which incorporates locking tabs and engagement pins which cooperate with the retaining members on the sensor housing.

Abstract: A marine speed sensor mounted in a housing which may also include a temperature sensor and a sonic transducer. The speed sensor includes a paddlewheel for producing an electromagnetic field. The paddlewheel is rotatably mounted adjacent the housing and exposed at top and bottom and mounted between support members extending from the housing.

Abstract: A marine speed sensor mounted in a housing which may also include a temperature sensor and a sonic transducer. The speed sensor includes a paddlewheel for producing an electromagnetic field. The paddlewheel is rotatably mounted adjacent the housing and exposed at top and bottom and mounted between support members extending from the housing.

Abstract: A through-hull speed sensor of the magnetized paddlewheel sensor type wherein a paddlewheel is rotatably supported in a cavity adjacent a magnetic sensing device which generates electrical pulses corresponding to paddlewheel speed as the wheel rotates when the vessel moves through water. The sensor has improved low speed characteristics provided by a housing which extends the paddlewheel into the water below the hull. The bow of the housing provides a new leading edge, generating a smaller thickness boundary layer at the paddlewheel, so that the paddles project beyond the layer at low speeds. High speed performance is improved by having a high ratio of paddle fore-to-aft drag coefficient shape; keeping the periphery of the paddlewheel hub within, or flush with, the bottom of the cavity; a low paddle projection versus paddlewheel radius ratio; and by keeping the ratio of paddle cross-section versus available cavity cross-sectional space within an optimum range.