Benthowave Instrument Inc.

BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System 

Flush-Mounting Hydrophone

Flush-Mounting HydrophoneFlush-Mounting HydrophoneFlush-Mounting HydrophoneFlush-Mounting Hydrophone

BII-7110  Flush-Mounting Hydrophone

BII-7110 series hydrophones mount through a hole or counterbore hole cut in the housing of underwater instruments, apparatus, vehicles or the wall of swimming pools. The flush-mounting design of these hydrophones minimizes surface discontinuity and allows for smooth water flow over the surfaces, meaning lower induced acoustic noise (hydrodynamic noise, flow noise), less drag/resistance, avoidance of accidental collision and better acoustic performance for the underwater devices in motion such as towed fish/bodies, ROV/AUV/UUV, robots, etc...
Low-profile flush installation protrudes only 4.75mm outside the housing with streamlined flange.

The housing can be mounted on different materials such as woods, plastics, fiber glass, ceramics and metals. Marine sealants shall be used for sealing, bedding and installation. The depth rating is limited by the sealing performance of the cured marine sealants.

BII-7110 hydrophones can be used as array elements to make up a linear, planar or conformal array which achieves unique acoustic performance.

Besides BII-7110 can work with fixed-gain preamplifier (such as BII-1010, BII-1060, BII-1050) to increase the sensitivity and drive long cable, it can also work with the programmable-gain preamplifier BII-1090 as a programmable-sensitivity hydrophone in field, and its sensitivity can be selected manually or with digital signal according to the underwater sound strength. please specify the preamplifier options when ordering.

If you do not find any transducer suitable to your project, please contact BII for custom designs on size, operating frequency, beam width, mounting, etc...

Technical Notes:
Signal Loss Over Extension Cable (dB) = 20*log[Ch/(Ch+Cc)];   Ch - Hydrophone Capacitance; Cc - Extension Cable Capacitance
Array directivity function = (directivity function of array element) * (directivity function of array pattern).

Receiving ArrayLine ArrayT ArrayCross Line ArrayCircular Array

Typical Beam Performance Specifications of BII-7110 Series :
Frequency: 3.5kHz 10kHz 26/28kHz 37.5kHz 45kHz 50kHz 70kHz 100kHz 120kHz 200kHz 300kHz 420kHz
-3dB Beam Width: 180° 180° 180° 102.4° 85.4° 76.8° 54.8° 38° 32° 19.2° 12.8° 9.1°

Side Lobes Information (Acoustic Axis at 0° normal to the receiving face):

Hydrophone: Critical Frequency fc: No Side Lobes Frequency: First Side Lobes at ±90° -3dB Beam Width @ fc
Operating Frequency: 78 kHz 105 kHz 50°

Towed Bodies, Vessels in Motion, Sonobuoy
Linear, Planar and Conformal Array
LBL/SBL/USBL Positioning System
Communication/Remote Control/Telemetry
Surface Continuity for Low Acoustic Perturbation
Direction-finding Sonar System
Monitoring Aquarium/Pool Safety/Alarm System/Underwater Security
Bioacoustic Research of Marine Animals
High Sensitivity
Broadband (Low Q)
Conical Beam
Low Flow Noise
Easy Installation/Mounting/Removing
1Hz to 500 kHz
Related Products    
Hydrophone Preamplifier Flush-Mounting Transducer


Mechanical Size:  No Preamp  Mechanical Size: Built-in Preamp Flush-Mounting with Counterbore Hole Low Profile Flush-Mounting
Flush-Mounting Hydrophone  Flush-Mounting Hydrophone  Flush Mounting Hydrophone  Flush-Mounting Hydrophone 


BII-7110 Series     BII-7111 BII-7112 BII-7116 BII-7117
Sensitivity (dBV/µPa): -195.0 -205.0 -195.0+Preamp Gain -205.0+Preamp Gain
Preamplifier Gain Options: N/A N/A 0/26/40dB 0/26/40dB
Capacitance (nF): 0.7 1.0 N/A N/A
Usable Frequency: 1Hz to 400kHz 1Hz to 500kHz 1Hz to 400kHz 1Hz to 500kHz
Equivalent Aperture: Disc, Φ23mm Disc, Φ23mm Disc, Φ23mm Disc, Φ23mm
Quality Factor: 2 2 2 2
Input Noise Density: N/A N/A 33 µPa/√Hz 33 µPa/√Hz
Beam Pattern: Conical Beam Conical Beam Conical Beam Conical Beam
-3dB Beamwidth: 3841°/f(kHz) 3841°/f(kHz) 3841°/f(kHz) 3841°/f(kHz)
Sidelobe Level: <-20 dB <-20 dB <-20 dB <-20 dB
Built-in Preamplifier: No No Yes Yes
Electronic Filter: N/A N/A Custom High Pass Custom High Pass
Output Type: Single Ended (SE) Single Ended (SE) 1. Single Ended (SE)
2. Differential (DF)
1. Single Ended (SE)
2. Differential (DF)
Cable: 1. Coax (ΦD2.8mm) (Coax)
2. Shielded cable(ΦD3.6mm)
3. Shielded cable(ΦD6.5mm)
1. Coax (ΦD2.8mm) (Coax)
2. Shielded cable(ΦD3.6mm)
3. Shielded cable(ΦD6.5mm)
Shielded cable
(ΦD6.5mm) (SC65)
Shielded cable
(ΦD6.5mm) (SC65)
Cable Length: 1. Default: 0.15m
2. Custom: Up to 3m
1. Default: 0.15m
2. Custom: Up to 3m
1. Default: 0.15m
2. Custom: Up to 50m
1. Default: 0.15m
2. Custom: Up to 50m
Supply Voltage: N/A N/A +8.5 to +24 VDC +8.5 to +24 VDC
Current: N/A N/A 0.85/1.2/4.8 mA 0.85/1.2/4.8 mA
Housing Size ΦDxH: 59.0/35x32.75mm 59.0/35.0x32.75mm 59.0/35.0x65.0mm 59.0/35.0x65.0mm
Weight: 300 grams 300 grams 400 grams 400 grams
Depth Rating: ≤100m, limited by the sealing performance of the cured marine sealants over the mounting hole.
For deeper underwater deployment (maximum 300m), one option is that O-ring grooves are cut on the mounting wall and O-rings are used besides marine sealants or casting sealants.
Flush Mounting: Counterbore hole shall be drilled or cut for mounting. Please refer to mechanical drawings.
Wall Thickness: ≤26mm, Fastening Torque: ≤14Nm, a nut is included.
Marine sealants are NOT included.
Low-Profile Mounting: Through-hole: Φ35mm, Wall Thickness: ≤21mm, Fastening Torque: ≤14Nm, a nut is included.
Marine sealants are NOT included.
Marine Sealants: BII does NOT provide Marine Sealants with the hydrophone. Buyer needs to buy Marine Sealants from buyer's local stores. Generally the stores that sell boats and boat repair part/material have marine sealants in stock, or buyer may use search engine to locate the suppliers online.
Connector Options: 1. Default: Wire Leads (WL)
2. BNC Male (BNC)
3. 3.5 mm (⅛″) TRS Plug (TRS35)
4. ¼″ (6.35 mm) TRS Plug (TRS635)
5. XLR Plug (XLR)
6. Underwater Mateable Connector (UMC)
7. MIL-5015 Style (5015)
8. +9VDC Battery Snap (BS) (Exclusive to preamplified hydrophone)
9. Custom (custom)
Suggested DC Supply
(BII-7116 & BII-7117)
+9VDC Battery, Marine Battery, Automobile Battery, Fixed DC Linear Power Supply, Not Included.
DO NOT use variable power supply whose maximum supply voltage is higher than the rated voltage.
DO NOT use switching mode DC power supply.
Operating Temperature: -10°C to +60°C
Storage Temperature: -40°C to +60°C
How to Order: Click How to Order.
Hydrophone Wiring: Click Hydrophone Wiring for detailed wiring information.
Receiving Array: Array & Aperture Design
Technical Documents: BII-7110 Series Hydrophone Sensitivity (RVR or OCV)

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