Edited by Alan L. Hitchcox, editor

When a non-standard pressure transducer was found to be causing the malfunction of the USS Abraham Lincoln’s list control system, an off-the-shelf TDG 01 transducer was modified with 9/16-in. threads and configured for vacuum to 85 psi service by Transducers Direct.
U.S. Navy photo by Photographer’s Mate 3rd Class Kittie VandenBosch

Pressure transducers come in a wide variety of sizes, shapes, fluid and electronic connection configurations, pressure ranges, and other essential parameters. Plus, the fluid shock and pulsations inherent to most hydraulic systems makes it even more difficult to find a suitable replacement when one fails in the field.

That’s just what happened aboard the USS Abraham Lincoln, a Nimitz-class aircraft carrier. While out at sea, the Lincoln’s list control system began malfunctioning, and the source of the problem was traced to a pressure transducer. List control keeps the ship from rolling about its longitudinal axis in rough seas. Without list control, takeoff and landing of aircraft could be compromised. And when you’re dealing with a $4.5 billion vessel, a jury-rigged solution is out of the question.

Internet helps find an answer
A sailor aboard the Lincoln searched for a replacement transducer on the internet and eventually contacted Transducers Direct, Columbus, Ohio. Rob Matthes, president of Transducers direct and a Navy veteran himself, was handling his company’s 24-hr service calls and answered the call from the sailor “somewhere at sea” late on a Thursday night.
The sailor found the pressure transducer he needed for the ship’s list control system on the Transducers Direct website. He wanted a replacement and a spare fast. Matthes explained, “They needed a transducer with a pressure port of 9/16 in., which is not standard. We could not ship the same day as we normally would, but we built the transducer on Friday based on a verbal order and waited for final instructions while the Navy worked out delivery issues. We got the formal order by e-mail Saturday and later exchanged several calls and e-mails regarding shipping requirements.”

The specific product provided was Transducers Direct’s stainless steel TDG 01 transducer configured for vacuum to 85 psi. It is manufactured using chemical vapor deposition to bond a polysilicon layer to a stainless steel diaphragm at the molecular level to produce a sensor with high long-term drift resistance and measurements with ±0.15% linearity and provides a 0- to 10-V or 4- to 20-mA output.

“On Monday we overnighted the transducers to Pearl Harbor, where they were put aboard a plane bound for the carrier,” said Matthes. “It was gratifying to provide a small piece of support to such a great warship in a pinch situation. We would have loved to learn more about how our transducer fits into the carrier’s list control system, but it was perhaps more interesting to learn just how powerful the internet is.”

For more information about Transducers Direct, call (513) 583-9491 or visit www.transducersdirect.com.