GB2472970A - Towed acoustic array - Google Patents
Towed acoustic array Download PDFInfo
- Publication number
- GB2472970A GB2472970A GB8613403A GB8613403A GB2472970A GB 2472970 A GB2472970 A GB 2472970A GB 8613403 A GB8613403 A GB 8613403A GB 8613403 A GB8613403 A GB 8613403A GB 2472970 A GB2472970 A GB 2472970A
- Authority
- GB
- United Kingdom
- Prior art keywords
- array
- towed
- tubular member
- water
- density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 9
- JMMZCWZIJXAGKW-UHFFFAOYSA-N 2-methylpent-2-ene Chemical compound CCC=C(C)C JMMZCWZIJXAGKW-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 5
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 229920002635 polyurethane Polymers 0.000 claims description 2
- 239000004814 polyurethane Substances 0.000 claims description 2
- 239000003000 extruded plastic Substances 0.000 claims 1
- 239000013535 sea water Substances 0.000 abstract description 11
- 229920003023 plastic Polymers 0.000 abstract 1
- 239000004033 plastic Substances 0.000 abstract 1
- 238000003491 array Methods 0.000 description 9
- 239000012530 fluid Substances 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000006424 Flood reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
- G01V1/3808—Seismic data acquisition, e.g. survey design
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/18—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using ultrasonic, sonic, or infrasonic waves
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Radar, Positioning & Navigation (AREA)
- Oceanography (AREA)
- Acoustics & Sound (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geophysics (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Transducers For Ultrasonic Waves (AREA)
Abstract
A towed acoustic array has a tubular member (S) of lightweight plastics material (e.g. methyl pentene) housing hydrophones (H) contained within a cable loom (C), in turn housed within the tubular member (S) and spaced therefrom by means of bristles (B). The array tube (S) is free-flooding with sea water which makes the array less sensitive to local density changes in the water in which it is towed so that a more stable and predictable towing performance is achieved.
Description
TOWED SENSOR ARRAYS
This invention relates to towed sensor arrays such as acoustic arrays which are used for passive detection of water borne vehicles and geological surveys.
The use of very long towed acoustic arrays for passive detection gives rise to a problem of buoyancy control in the array. The problem is greatest when arrays of up to 3 kilometres are towed at slow speeds.
The array may drift to the surface or may drag along the seabed in water of varying density, and either departure from near horizontal is undesirable.
Currently it is the practice to make towed arrays neutrally-buoyant by using a filling fluid with a specific gravity less than that of sea water, in order to offset the weight of components such as cables and hydrophones which make up the array. The overall density of the array is determined by the amount of low density fluid which is pumped into the array. Obviously the density of the array is fixed at the time of filling.
This method of controlling the buoyancy means that when the array encounters a range of sea conditions, there will be varying degrees of mismatch between the density of the array and the density of the surrounding sea water. Sea water density is a function of depth, temperature and salinity, all of which can change quite suddenly during towing operations.
One example of a prior art towed acoustic array
is described in British Patent Specification 2149916A (M.J. Bryant et al 5-4). This shows diagrammatically a towed array comprising a number of node sections. The node sections comprise electronic hardware and the "correct" degree of buoyancy in the nodes is achieved with a gel comprising a synthetic hydrocarbon polymer having a high viscosity and a relative density of less than 1.0 loaded with particulate material having a relative density of less than 0.5 and typically 0.3 to 0.4.
It is an object of the present invention to minimise if not overcome the above problems in a towed acoustic array.
According to the present invention there is provided a towed sensor array comprising sensors connected to an elongate tubular member, said member being free flooding with the water in which it is towed.
In order that the invention can be clearly understood reference will now be made to the accompanying drawing which shows somewhat schematically an in cross-section the central core of a towed acoustic array according to an embodiment of the present invention.
Referring to the drawing the central core of the array comprises a tubular member S made, in this embodiment, of methyl pentene (extruded), and a cable loom C which carries the signals from hydrophones such as H spaced at intervals along the length of the tube.
The cable loom C is supported substantially centrally of the tube S by means of radially extending bristles B which are fixed to the cable loom C and centralise the cable loom and the hydrophone assembly within the tube.
In the spaces sea water SW floods freely through the tube from one end to the other.
Each cable of the cable loom C is a twisted pair with methyl pentene insulation.
The bristles B are made of thin nylon filaments so as to minimise the transmission of flow noise between the outer skin of tube S and the core by these filaments as the array is drawn through the water and the sea water SW floods through the tube. Furthermore any drag forces are absorbed in the re-inforced skin of the tube S. By having a sufficient density of radial filaments it is possible to attenuate the longitudinal waves which are a source of flow-induced noise in conventional towed arrays.
When the array is recovered onto a winch, the sea water SW is allowed to drain out. The array then collapses Onto the core and achieves a much-reduced cross-section with consequent reduction in winch capacity and space.
The design described overcomes the lack of controllability of array density previously experienced, by means of the "free-flooding" arrangement. Thus high density polymers such as polythene and polyurethane which are used on conventional arrays, have been replaced with a low density material such as methyl pentene (marketed as IPX by the Mitsui Company of Japan). All cable insulation is performed using the same material (methyl pentene), the end result being that the solid parts of the array alone achieve neutral buoyancy at a mid-range of sea water densities. The average density of the array components is designed to be 1.025 S.G. to give a match to the mid-range of sea water densities. The interior of the array, inside the polymer skin, is allowed to flood freely with the sea water, and a means is provided for a certain rate of exchange of water through the tube so that the array always contains water of the same density as the surrounding sea.
By designing the array to contain as much as two thirds of its total volume in sea water, the sensitivity of array density to changing temperatures and pressures is much reduced. Added advantages of the "free flooding array" are that leakage of the outer skin is no longer critical and the hazard of possibly having large amounts of flammable fluids such as those currently used for buoyancy control in conventional arrays, is eliminated.
There are also weight and space saving benefits for the towing vessel.
Although the embodiment described is specifically for a hydrophone sensor array, the present invention is equally applicable to other forms of towed arrays of sensors, e.g. acoustic, magnetic, electromagnetic.
Claims (6)
- CLAIMS -1. A towed sensor array comprising sensors connected to an elongate tubular member, said member being free flooding with the water in which it is towed.
- 2. An array as claimed in claim 1, wherein the tubular member is made of an extruded plastics material with a density which is low in comparison with that of polythene and polyurethane.
- 3. An array as claimed in claim 2 wherein the material is methyl pentene.
- 4. A towed sensor array comprising a plurality of sensing elements, an elongate tubular member containing said sensing elements along the length thereof, and means for supporting the sensing elements within the tube in is such manner that the tube remains free-flooding with the water in which the array is towed.
- 5. An array as claimed in claim 4, wherein the sensing elements are spaced from the inner wall of the tubular member by means of radially extending bristles.
- 6. A towed acoustic array substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8613403A GB2472970A (en) | 1986-06-03 | 1986-06-03 | Towed acoustic array |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8613403A GB2472970A (en) | 1986-06-03 | 1986-06-03 | Towed acoustic array |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8613403D0 GB8613403D0 (en) | 2010-04-07 |
| GB2472970A true GB2472970A (en) | 2011-03-02 |
Family
ID=42113920
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8613403A Withdrawn GB2472970A (en) | 1986-06-03 | 1986-06-03 | Towed acoustic array |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2472970A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114910154B (en) * | 2022-04-26 | 2023-12-05 | 南京锐声海洋科技有限公司 | Side-hanging hydrophone fiber damping array and preparation method thereof |
-
1986
- 1986-06-03 GB GB8613403A patent/GB2472970A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB8613403D0 (en) | 2010-04-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5745436A (en) | Semi-dry marine seismic streamer cable section | |
| US4955012A (en) | Seismic streamer cable | |
| US4809243A (en) | Streamer cable | |
| CA1195396A (en) | Hydrophone cable comprising loosenable braided members | |
| US4160229A (en) | Concentric tube hydrophone streamer | |
| AU2007201880B2 (en) | System for reducing towing noise in marine seismic survey streams | |
| US7518951B2 (en) | Systems and methods for seismic streamer positioning | |
| US6879546B2 (en) | Gel-filled seismic streamer cable | |
| US7545703B2 (en) | Marine seismic streamer with varying spacer distances for reducing towing noise | |
| US20080186803A1 (en) | Fluid filled sensor mount for gel-filled streamer and streamer made therewith | |
| AU2007242934A1 (en) | Seismic streamer having directionally sensitive sensors in an array to attentuate longitudinally traveling waves | |
| US3930254A (en) | Seismic streamer construction for minimizing hydrophone response to vibration produced pressure fields | |
| US3781778A (en) | Marine streamer cable | |
| US4689777A (en) | Filled hydrophone mounts | |
| US20170146676A1 (en) | System and Method of a Buoyant Tail Section of a Geophysical Streamer | |
| US2570707A (en) | Seismic surveying | |
| GB2472970A (en) | Towed acoustic array | |
| US2607842A (en) | Marine seismometer spread | |
| US3287691A (en) | Hydrophone cable | |
| US4837751A (en) | Shielded hydrophone assembly | |
| CA2092665C (en) | Marine-seismic streamer having a device for damping vibrations | |
| US2638176A (en) | Marine seismic surveying | |
| AU778621B2 (en) | Low-noise towed acoustic linear antenna | |
| US10133017B2 (en) | Vented optical tube | |
| BR102014005167A2 (en) | CORDAN DESIGN FOR GEOPHYSICAL PROSPECTION |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |