Vessel with active mechanism for controlled towing

Abstract

A vessel for towing a towed body in or on a body of water is disclosed. The vessel includes a vessel, a tow arm mechanism carried by the vessel, a towed body linked to the tow arm mechanism, and at least one sensor carried by either the vessel or the towed body. The sensor generates sensor data, and a towing mechanism controller receives the sensor data and positionally adjusts the tow arm mechanism based on the data.

Description

TECHNICAL FIELD[0001]Generally, the present invention relates to vessels that tow sensors. Specifically, the present invention is directed to vessels that tow sensors with a towing arm that has an end that is movable so as to minimally offset a towline force vector from the vessel's center of gravity. In particular, the present invention is directed to vessels that tow sensors wherein the vessel and / or towed body is provided with a motion and position sensor to detect changes in the towline force vector so as to actively move the towing arm to compensate for those changes.BACKGROUND[0002]Various types of sensors are utilized for evaluations of bodies of water. These sensors can be used for seismic surveys, sea floor mapping, and environmental and coastal surface surveys. These sensors can also be used to detect underwater conditions for military purposes such as for surveillance, the detection of mines and / or other submerged vehicles.[0003]One method is to tow a sensor from an airc...

AI Technical Summary

Benefits of technology

[0027]Utilization of system 10 with the control system 126 which incorporates the controller 20 provides a number of advantages. First, towing a body from a multi hull vessel provides greater flexibility for controlling the tow point to reduce deleterious effects through the opening 28 between the multiple hulls both laterally and longitudinally on the craft. In other words, by utilizing an active mechanism for controlling the position of the tow vector, it will be appreciated that its path is positionable through or very close to the center of gravity of the vessel, or through the thrust vector of the propulsor or some optimal position of compromise between the two. Still other advantages are realized in that towing of a towed body 52 in areas of high sea states dictates a preference for the towing vessel to be a multi hull configuration due to its superior sea keeping and sea-kindliness. This improved sea keeping reduces the towing vessel's motion which, in turn, reduces the imposed motions on the towed body. Improved sea keeping also improves the effectiveness of the controlling and gathering of information from the towed body in the case of a manned vessel, or improves the ability to control through improved remote sensing capabilities in case of an unmanned tow vessel. Additionally, use of multi hulls allows for faster transit time to the area of interest for the sensor in tow.

Problems solved by technology

It is known that small craft used to tow sensors have difficulty in controlling the impact of the towing vessel's motions on a towed sensor and also conversely, the impact of the towed sensor's forces on the attitude of the towing craft are encountered.

This tow point location away from the vessel's center of gravity allows vessel pitch motion to be transmitted to the tow line tension and this results in unwanted sensor motion.

And the distance of the tow point from the vessel's center of gravity and the resulting couple motions of pitch and heave, and towing from an A-frame also imposes higher forces on the towed body, thereby degrading its motion performance.

It also generates a force vector significantly away from the towing vessel's center of gravity, thereby imposing moments that are deleterious to the vessel's performance.

Moreover, the tension from the drag of the sensor and tow line, in turn, adds to the vessel trim and roll angles.

Adding roll and yaw moment to a vessel impacts on-board equipment performance and hinders the ability to control the vessel.

In addition, the sensor is exposed to transverse currents, waves and wind forces which further contribute to the deleterious forces imparted on the vessel.

These forces also provide extra wear on the tether connecting the vessel to the towed sensor.

In summary, prior art small craft vessels that tow a sensor usually do so from a non-optimal fixed point and such small craft have no way of adjusting the fixed point to accommodate operational characteristic of the vessel or environmental characteristics that are encountered while towing the sensor.

Indeed, a towed sensor that is exposed to extraneous forces interferes with the main purpose of the sensor in collecting data.

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