Sea Technology

JUL 2018

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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www.sea-technology.com July 2018 | ST 11 submarines that are lightweight, intuitive to operate and provide a unique, three-di- mensional underwater flight experience, with a simple cockpit enabling operators to safely dive with minimal training. Most per- sonal submarines are based on designs for research-focused tasks, making them heavy and complex to operate, but the DeepFlight Super Falcon 3S was specifically designed for tourism and ease of operations. The sub is also the first composite-hulled submarine to be certified by Lloyd's Register. The use of composites allows the company to build high-strength, low-weight craft that are the most lightweight submarines on the market. DeepFlight is committed to being environ- mentally friendly, so its submarines do not have skids (and, therefore, cannot land on reefs or the seafloor), have low acoustic emissions and are low voltage, meaning they are safe to operate around swimmers and marine life. The custom penetrator assemblies are robust sys- tems that safely and reliably transmit electrical power or signal through a pressure boundary without com- promising its integrity. One of the many advantages of penetrators is that they decrease the complexity of electrical systems and reduce dependence on op- erator skill, requiring minimal maintenance, and are suitable for long-term deployment in harsh marine en- vironments. To that end, the BIRNS custom penetrators featured polyurethane overmolding on the outboard side, with robust inserts and O-rings, and rigorous ABS-compliant testing protocols. Assembly Functions The DeepFlight Super Falcon 3S required a total of 16 penetrator assemblies for functions on board ranging from navigation and communications to battery pow- er. The penetrators had 1.5-in. hex flats and anodized 1-in. aluminum shells, versus the standard stainless, as they were to be mounted to an aluminum bulkhead and DeepFlight needed the materials in contact to be the same to avoid galvanic corrosion. DeepFlight's hull and pressure bottle penetrations for the project were already designed but did not match any standard penetrator siz- es, so BIRNS adapted a BIRNS Millennium 3P connector shell with 1-20 UNEF threads to fit the system and de- veloped custom 25 pin inserts for the assemblies. These custom penetrators had cables using 20 to 16 AWG conductors and conductor counts from two to 24 with maximum voltage per wire of 44 V, maximum current of 4 A continuous per conductor and maximum power required of 250 W, and came in a range of cable design configurations. For navigation and other relevant functionality on the sub, BIRNS supplied two EH-2 assemblies, each with a single P25 penetrator, with a 27-in. Y cable leading to four wetmate five-pin connectors. This cable harness connected the depth transducer, altimeter, Tritech Mi- cronNav tracker and Micron data modem to the pressure (Top to bottom) EH-7 cable is inspected before moving on to final IR testing. Final continuity testing is carried out on each assembly, to ensure that all circuits are operational. Two EH-3 penetrator assemblies transmit primary power from the port battery to the pressure hull for inboard elec- tronics.

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