Sea sled tow line vector system

In a subsurface towing system, wherein a subsurface body is towed by a surface tow vessel, said towed body and surface vessel being connected by cable means, a method of remotely monitoring the attitude of said towed body, comprising:

• measuring first and second force components acting on said cable means;
• measuring third and fourth force components substantially orthogonal to said first and second components;
• determining a first net force component acting between said cable and said towed body from said first and second force components;
• determining a second net force component acting between said cable means and said towed body from said third and fourth force components;
• determining a first direction deviation of said cable means relative to a reference axis of said towed body from the first net force component and at least one of said first and second force components;
• and
• determining a second deviation of said cable means in a second direction substantially orthogonal to said first direction from said first and second net force components.

In an undersea towing system, wherein a body is towed along the sea bottom by a surface tow vessel connected to the towed body by a tow cable through a tow cable bridle, a method of remotely monitoring the attitude of said towed body, comprising:

• measuring a first relatively horizontal force component along one leg of an isosceles triangle formed by the tow cable bridle;
• measuring a second relatively horizontal force component along a second leg of said isosceles triangle;
• measuring a first relatively vertical force component at the base of said one leg of said isosceles triangle;
• measuring a second relatively vertical force component at the base of said second leg of said isosceles triangle;
• determining the net relative vertical force acting on said tow cable from said first and second vertical force components;
• determining the resultant relative horizontal force acting on said cable from the measured first and second horizontal force components;
• determining the relative horizontal deviation of said cable relative to the longitudinal axis of said towed body from the determined resultant horizontal force and at least one of said first and second measured horizontal forces;
• and
• determining the relative vertical deviation of said cable relative to a horizontal reference plane containing the horizontal axis of said towed body from the determined net vertical force and resultant horizontal force.

In a subsurface towing system, wherein a subsurface body is towed by a surface vessel, apparatus for monitoring the attitude of said towed body, comprising:

• tow cable means coupled between said surface vessel and said towed body;
• means for measuring first and second relatively orthogonal force components acting on said cable means where said cable means is coupled to said towed body;
• and
• means for determining first and second relatively orthogonal deviations of said cable means relative to said reference axis from said measured first and second relativley orthogonal force components.

Apparatus for measuring forces acting on a tow line, comprising:

• a towed body;
• a tow line bridle, including a first length of tow line having one end coupled to said towed body at a first location and a second length of tow line having one end coupled to said towed body at a second location, the second ends of said first and second tow line lengths being coupled together, whereby said first and second tow line lengths form two legs of a reference triangle;
• a tow line connected to and extending from the junction of said first and second tow line lengths;
• first detecting means at said first location for detecting first relatively orthogonal force components acting on said tow line;
• second detecting means at said second location for detecting second relatively orthogonal force components acting on said tow line;
• first measuring means coupled to said first and second detecting means for measuring the deviation of said tow line in a first direction relative to a central longitudinal axis of said towed body;
• and
• second measuring means coupled to said first and second detecting means for measuring the deviation of said tow line in a direction substantially orthogonal to said first direction.

In a subsurface towing system, wherein a subsurface body is towed by a surface vessel, apparatus for monitoring the attitude of said towed body, comprising:

• tow cable means coupled between said surface vessel and said towed body;
• means for measuring first and second non-colinear forces acting between said cable means and said towed body where said cable means is coupled to said towed body;
• and
• means coupled to said measuring means for determining deviations of said cable means relative to a reference axis of said towed body from said measured first and second forces.