Underwater & Marine

Underwater construction activities like blasting and pile driving create overpressure that can put marine life and ecosystems at risk.

Why Monitor Your Underwater Projects?

Underwater construction activities can produce vibrations that travel through the water, away from the source, as shock waves. These shock waves are measured in terms of pressure and are often referred to as overpressure. They can have a detrimental impact on marine life and ecosystems. When overpressure levels are high enough, they have the potential to cause physiological or behavior changes in fish and other marine mammals. Potential effects can cause injury and have an adverse impact on health and reproduction. Overpressure can also impact the sonar abilities of marine mammals and cause damage to habitat structures like coral reef. While underwater activities typically cause higher overpressure levels, construction activities that are nearby water can also transfer these vibrations into the water. Bubble curtains are often used to reduce and localize the impact of these effects. However, even under best case scenarios these activities can still have long lasting effects.

How Instantel Can Help

With equipment from Instantel, you can record and monitor the overpressure levels induced by your construction activities. As recorded data can be viewed almost immediately, you have the ability to adjust the activities creating the overpressure before regulatory limits are exceeded or before concerns develop. Warnings and alarms can be configured based on preset trigger levels, which can be different for each job. Notifications can be sent to your phone, tablet, computer or other internet connected devices. You can also pair the Instantel monitoring equipment with an on-site audible or visual alarm so workers can adjust their activities before a trigger level is reached.

The Minimate Pro Monitoring System

Minimate Pro4
Splitter Box Microphone

Minimate Pro4


Splitter Box Microphone

Monitoring unit with either four or six channels and sample rates up to 65 kHz. Measures overpressure in water. Can be installed up to 250 feet deep. Required to configure the Minimate Pro to monitor with more than two hydrophones.

Since the effects of these activities can have long term side effects, local, state and federal regulations govern the levels of overpressure that can be induced by construction or other activities. The Instantel Minimate Pro monitoring unit records overpressure data measured with a hydrophone. The hydrophone from Instantel is encased in a waterproof, high impact polyurethane, designed to be used at depths of up to 250 feet. It records frequencies from 8 to 500 Hz and can measure pressure changes up to 47 psi. Overpressure underwater can be higher in frequency but short in duration. Recording at a higher sample rate can ensure that peaks are not missed. The Minimate Pro monitors at sample rates of up to 65 kHz to give you better resolution in your data.

Installation is easy – just connect the hydrophone to the Minimate Pro monitor and drop it into the water. The hydrophone will take an ambient pressure reading and then record any changes in that pressure. The Minimate Pro is available in two models: the Minimate Pro4 and the Minimate Pro6. The Minimate Pro4 has four available channels and can support up to four hydrophones, while the Minimate Pro6 has six available channels for support of up to six hydrophones. By connecting more than one hydrophone, you can monitor overpressure in more than one location and synchronize the readings using one machine. If one hydrophone is triggered by an exceedance, the others will record overpressure data in their respective locations as well.

Bubble curtain used for underwater monitoring
Underwater Monitoring with Bubble Curtain

How A Minimate Pro Series Monitoring System Connects Using THOR Advanced and Vision Software Systems

Hydrophone report graph

THOR Advance

Using Instantel’s Auto Call Home technology, monitoring units connected to a modem can automatically send event data to your computer so you can analyze the data using THOR, our desktop software. THOR’s advanced analysis tools let you convert the waveforms to third octave bands and frequency filter. You can also add markers to event data to pinpoint precise timings or frequencies. These will be saved on the pdf reports. With THOR’s project features, you can sort your event data into projects and configure automatic email notifications of warnings or alarms for each project.

Instantel’s underwater monitoring is easy to configure and install. Our equipment is scalable. If today you are monitoring underwater and need a hydrophone but tomorrow you need to monitor ground vibrations, you can simply remove the hydrophone and add a triaxial geophone. Our equipment is rugged and reliable – the Minimate Pro is water resistant and can handle anything your job can throw at it.