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Universal Sonar Mount Designed for Precision

A USM hinge option sonar mount on a NOAA NRT2 survey vessel. The Z-pole with attached sonar head is stowed along the gunwale, out of the way of activities on the boat. When deployed again, the sonar will maintain calibration. At the time of installation, this boat was helping post-Sandy survey operations in New York City.

A USM hinge option sonar mount on a NOAA NRT2 survey vessel. The Z-pole with attached sonar head is stowed along the gunwale, out of the way of activities on the boat. When deployed again, the sonar will maintain calibration. At the time of installation, this boat was helping post-Sandy survey operations in New York City.

Universal Sonar Mount (USM) is a high quality marine sonar equipment mount that was designed by a hydrographer, a precision parts manufacturer and a clock engineer.

Five years ago, hydrographer Brent von Twistern was the chief hydrographer establishing a hydrographic survey operation in San Francisco Bay, and he purchased equipment from Reason Bradley, who operates a mechanical laboratory in Sausalito. Von Twistern had been dealing with unstable and hard to use overtheside mounts for transducers and other equipment, and he and Bradley came up with the idea of a dedicated universal mount that would eliminate the time and money consuming problems inherent in existing sonar mounts.

They enlisted the partnership of Greg Staples, who is a clock engineer with the Long Now project’s 10,000 year clock, a massive timepiece in the center of a mountain that comprises a myriad of precision moving parts.

According to von Twistern, the two features that set the USM apart are calibrated breakaway and repeatable pole technology, which are made workable by sturdy construction of the poles and extremely tight tolerances on the moving parts.

Calibrated breakaway allows the unit to release if it hits something, protecting the vessel, the crew, the sonar and the project. A 10-minute fix will have the survey under way again. The impact is absorbed by a one-inch by one-inch by three-inch “breakaway shear block” made of a proprietary marine plastic material installed on the sonar mount, which allows the user to quickly and precisely raise and lower the Zpole. The fix consists simply of taking out the damaged shear block by removing a fastener and a nut, and inserting a new one. Because the shear block is highly engineered and calibrated, the calibration of the sonar is not lost, so a new patch-test is not needed, and the survey can resume immediately.

Repeatable pole technology makes it possible to move the Z-pole out of the water without losing the sonar’s calibration. If it is necessary to raise the pole or stow it to move to a new location, it will not be necessary to re-calibrate. The unit can be deployed and the survey continued.

USM customizes the flange mount at the end of the pole to match the sonar product the customer intends to use, and will provide a different flange if the customer changes equipment. All the parts are machined in the Universal Sonar Mount Sausalito facility.

A single point mounting provides stability, allowing a survey to proceed with no wobble or oscillation in the Z-pole. A fixed plate is welded, clamped or bolted to the gunwale of a survey vessel or vessel of opportunity, and the unit is bolted to the plate. There are a number of configurations for deployment, depth, yaw, pitch and width, the most versatile being the hinged plate, which allows the entire unit to swivel up to stow along the gunwale for storage – out of the way of operations on deck.

Depending on the type of brackets included, the unit can weigh from 80 to 150 pounds.

The presence of the company in Sausalito, across the bay from San Francisco, is significant, von Twistern said. It was there that Liberty Ships were built during WWII, and the maritime presence and expertise has remained in the community. Reason Bradley has a lathe in his laboratory that was used in Liberty Ship manufacture, he said.

The company has an impressive list of dredging and shallow water survey customers, including Manson Construction Company, Dutra Dredging, eTrac Engineering, NOAA, the Naval Oceanographic Office – and now Chris Ransome Associates (see related article on pg. xx.)

The USM website – www.universalsonarmount.com -- mirrors the technical precision of the product, with concise descriptions of the technology, photos of installations, drawings of all components, and short videos of the operations, including changing out the breakaway shear block, the hinge option in action, deploying the unit, unpacking and installing the Zclamps, and much more, which give the viewer a visual of the quality of the equipment as well as instructions on installation and operation.

Von Twistern showed the USM on a survey vessel at HYPACK 2012 in San Diego, where it was very well received, he said. Other shows were OI in 2012 and 2014, where there was “a bit of a buzz surrounding our products,” and at the Work Boat Show in New Orleans in 2013

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