Towfish with reversible variable hydrodynamic lift and towing line comprising the towfish

Patent metadata

Field	Value
Publication number	US-11396348-B2
Application number	US-201816955032-A
Country	US
Kind code	B2
Filing date	Dec 18, 2018
Priority date	Dec 19, 2017
Publication date	Jul 26, 2022
Grant date	Jul 26, 2022

Abstract

A body towed by a cable behind a ship and commonly referred to as a towfish, the towfish includes a structure configured to move through the water in a horizontal main direction and at least one appendage configured to generate on the towfish a downwardly directed hydrodynamic lift (P) when the towfish is moving through the water under the effect of the towing, the appendage being orientable so as to modify its lift. The towfish comprises a bracket capable of rotational movement with respect the structure about a horizontal axis perpendicular to the horizontal main direction, the cable being attached to the bracket. An orientation (γ) of the appendage, allowing it to alter the lift (P), is dependent on an angle (β) formed between the bracket and the structure about the horizontal axis.

First claim

The invention claimed is:

1. A towfish configured to be submerged and towed by a cable, the towfish comprising:
a structure configured to move through water in a horizontal main direction and at least one appendage configured to generate on the towfish a downwardly directed hydrodynamic lift when the towfish is moving through the water under the effect of towing, the appendage being orientable so as to modify lift on the appendage,
the towfish comprising a bracket capable of rotational movement with respect to the structure about a horizontal axis perpendicular to the horizontal main direction, wherein the cable is configured to be attached to the bracket, comprising a non-motorized mechanism configured so that an orientation of the appendage, allowing the lift on the appendage to be altered, is dependent on an angle formed between the bracket and the structure defined on the basis of the horizontal main direction, and wherein a law connecting the angle to the orientation of the appendage is configured so that when a value of the angle decreases, the orientation of the appendage is increased in such a way as to reduce the hydrodynamic lift on the towfish,
wherein the towfish has a weight and is subjected in the water to an upthrust force, such that a resulting force of the weight of the towfish and upthrust force on the towfish directs the towfish downwards,
further comprising a cam and a cam follower, one being secured to the appendage and the other to the bracket, and wherein the cam follower presses against a shape on the cam as the bracket rotates about the horizontal axis.

2. The towfish as claimed in claim 1 , wherein over a range of values for the angle, the law is unstable so that a given value for the orientation of the appendage leads to a reduction in the angle.

3. The towfish as claimed in claim 1 , wherein beyond a first given angle value, the orientation of the appendage is fixed so as to generate an operational lift of the towfish, and wherein below the first given angular value, the orientation of the appendage is increased as the value of the angle decreases so as to reduce the lift on the appendage compared with the operational lift.

4. The towfish as claimed in claim 3 , wherein below a second given angular value less than the first given angular value, the orientation of the appendage is fixed so as to generate an evasion lift lower than the operational lift.

5. The towfish as claimed in claim 4 , wherein below the second given angular value, the orientation of the appendage is positive or zero.

6. The towfish as claimed in claim 4 , wherein there is defined a third angle value intermediate between the first and second angle value, and wherein, between the first and the third angle value, a law connecting the angle to the orientation of the appendage is configured to keep the angle at a stable value.

7. The towfish as claimed in claim 4 , wherein the range of values for the angle wherein the law is unstable is defined between the third and the second angle value, and wherein the law is configured in such a way as to orient the appendage in order to achieve the evasion lift.

8. The towfish as claimed in claim 1 , comprising a lift-inducing airfoil forming the appendage, and a stabilizing empennage configured to keep a pitch attitude of the towfish substantially constant during changes to the orientation of the appendage.

9. The towfish as claimed in claim 1 , wherein the appendage is able to move in rotation with respect to the structure about a second horizontal axis, a mobility of the appendage allowing the hydrodynamic lift on the towfish to be modified, and wherein the second horizontal axis of rotation of the appendage is positioned substantially at an instantaneous center of rotation of the towfish when the latter pivots as a result of a change in the orientation of the appendage.

10. The towfish as claimed in claim 9 , wherein beyond a first given angle value, the orientation of the appendage is fixed so as to generate an operational lift of the towfish, and wherein below a first given angular value, the orientation of the appendage is increased as the value of the angle decreases so as to reduce the lift on the appendage compared with the operational lift, further comprising a first latch configured to keep the appendage in a fixed orientation when the value of the angle is beyond the first given angle value.

11. The towfish as claimed in claim 1 , wherein below a second given angular value less than a first given angular value, the orientation of the appendage is fixed so as to generate an evasion lift lower than an operational lift further comprising a second latch configured to immobilize the bracket with respect to the structure when the value of the angle formed between the bracket and the structure is below the second given angle value.

Assignees

• Thales Sa

Inventors

• Cadalen François
• Warnan François
• Jezequel Olivier
• Longuet Jean-Philippe
• Vicariot Philippe

Classifications

• G01V1/3826

  dynamic steering, e.g. by paravanes or birds · CPC title

• B63G8/42

  Towed underwater vessels · CPC title

• B63G8/18 Primary

  by hydrofoils · CPC title

• G01S15/89

  for mapping or imaging · CPC title

• B63B21/66 Primary

  Equipment specially adapted for towing underwater objects or vessels, e.g. fairings for tow-cables ({paravanes for dragging fishing nets A01K73/02; } salvaging underwater vessels or objects B63C7/00; towed underwater vessels B63G8/42) · CPC title