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www.sea-technology.com February 2015 / st 21 D ivers face some of the harshest environments when performing underwater inspections, such as diving in blackwater conditions with little or zero visibility, excessive tidal variations, strong currents and extreme weather conditions. So, for a diver undertaking metal thickness measurements of ship- wrecks, offshore platform legs or underwater pipelines, the ability to easily navigate around obsta- cles unhindered is essential. The Cygnus DIVE underwater thickness gauge has been designed for the professional diver undertaking metal thick- ness measurements and can withstand the most extreme diving environments. With its super-bright AMOLED display and large numbers, thickness measurement readings are visible even in poor conditions. With the optional HelmetView heads-up display mount- ed to the diver's helmet, readings can be seen even in blackwater. The Cygnus DIVE is wrist- mountable, which allows one hand to remain free while carrying out the thickness survey. The ability for the diver to wear Cygnus In- struments Ltd.'s (Dorchester, England) Cygnus DIVE on his or her arm or wrist is a big advan- tage. Having a free hand when diving offers clear benefts, and together with the 2.8-inch quar- ter AMOLED color display, the device makes viewing so much easier by both the diver and support engineers on the surface via the diver's camera. The AMOLED display offers a big view- ing advantage, especially in poor visibility. Other key features of the Cygnus DIVE in- clude the multiple-echo and single-echo measuring modes, A-Scan display, stable measurement indicator, data logging and topside repeater with video overlay. A7 Project In the summer of 2014, a team of divers from the A7 Project, the goal of which is a nonintrusive archaeological survey of the wreck of the Royal Navy submarine A7 lost in Plymouth Sound in 1914, purchased a Cygnus DIVE thick- ness gauge so that they could measure the metal thickness of the HM submarine A7 (HMS/M A7) to determine the current condition of the submarine and to monitor its de- terioration over time. "We used the 5-megahertz dual crystal as it gave the best results on the pitted steel we found on the many cor- roded ships hulls where we tried the ultrasonic thickness gauge," Peter Holt, project manager for ProMare UK, said. "The DIVE was reli- able, very easy to use, and has a simple menu system and displays. The logging function was essential as we only had 13 minutes on the wreck each day. I could make lots of measurements and fgure out the answer back home in post-processing. We also didn't have to write any- thing down or think too much as thinking isn't so easy in 40-meter water with the effects of narcosis." The A7 Project, grant- ed access by the Ministry of Defence, is part of the SHIPS (Shipwrecks and His- tory in Plymouth Sound) Project, which is funded by ProMare UK. Versatile Measuring Modes The well-established Cygnus multiple-echo mea- suring mode, using a single echo probe, has long since been the industry standard and endorsed by the world's leading classifcation societies for measuring the remaining Keeping Divers Safe During Subsea Metal Thickness Inspections Equipping Divers with the Ultimate Thickness Gauging Kit By Graham Haines (Top) The super-bright AMOLED display is ideal for blackwater conditions where vis- ibility is poor. (Middle) The wrist-mountable underwater ultrasonic thickness gauge en- ables an invaluable free hand for divers. (Bottom) Divers approach the Elk wreck as part of the A7 Project. (Photo Credit: The SHIPS Project)