Uncrewed Systems Technology 044 l Xer Technolgies X12 and X8 l Lidar sensors l Stan UGV l USVs insight l AUVSI Xponential 2022 l Cobra Aero A99H l Accession Class USV l Connectors I Oceanology International 2022

95 pressure and corrosiveness of seawater mean that connectors running through the flooded hulls of large and extra- large UUVs often have to consist of wet-mateable, rubber-moulded or epoxy- potted plugs. These are highly effective, but as is the case with pretty much any kind of moulding or potting, producing them is time-intensive and is a tightly controlled and costly process. That has driven a few manufacturers aiming at the marine market to seek ways of producing a safe, secure underwater connector that requires no potting or over-moulding. One of the most notable new solutions in this regard is a press-fit connector, which is built using a stainless steel shell with a PEEK (polyether ether ketone) insulator base holding the pins in place once they are pressed into the plastic. Although they have not yet been tested to their absolute limit, they have so far been proven to 600 m depth, making them suitable for missions in the riverine and littoral operations increasingly dominated by micro-AUVs. That suitability is reinforced by the fact that they can be produced around 10 times faster than their conventional moulded equivalents – a critical improvement given that standard marine connector lead times are often around 12-18 weeks – and cost around half as much. This is further aided by the use of a barbed connection sleeve around the back end of their housings, which cable harness jackets can slide around and grip onto for a watertight seal, accelerating the production process of complete cable- and-plug systems for marine vehicles. While these connectors are not wet-mateable, they remain ideal for manufacturers of UUVs that are unlikely to require their connections to be unplugged and reconnected underwater. And many vehicles are now designed to have slightly reduced capabilities than the high-end UUVs for the defence and petrochemicals industries in exchange for enormously lower production costs, making these sorts of connectors an ideal match. Another notable innovation in this vein is a compression gland cable penetrator, which seals cables to a depth of 950 m. While not the traditional type of connector that uses male and female pin contacts, penetrators nonetheless allow users to add removable cable connections to an enclosure. Potted penetrators have grown enormously in popularity over the past several years, but have weaknesses in terms of reliability and robustness. The compression gland penetrator design combines a rubber seal with a carefully designed internal geometry to achieve high-pressure performance without the use of potting materials, and they can be installed in just a few seconds. Products such as these are helping to drive the boom in micro-AUVs for global environmental research and inspecting tight spaces inside sewers, storage tanks and so on. For long-endurance XLUUVs travelling down to 6000 m depths however (perhaps the second-fastest growing portion of the UUV industry), much stronger and more rugged designs are needed. A certain measure of ruggedisation makes a connector ideal for use in the air as well as at sea. For instance, some circular connector developers design their products for IP68 rating, which means they can safely be submerged in different chemicals and solutions. That can make such designs useful for a USV or micro-AUV with plugs that might need to be submerged in up to 20 m of water for 2 hours, or for data or power connections around an aircraft engine where oil, fuel or coolant could spill. And the use of such connectors goes beyond cable harnesses. Highly ruggedised flash drives have been popular for some time in motorsport for exporting car telemetry to a removable, physical device that will not be damaged by severe vibration, heat or splashing from race fuel or oil, and can be quickly removed and replaced during pit stops. Connectors | Focus A certain measure of ruggedisation makes a connector ideal for use in the air as well as at sea. For instance, some are designed for IP68 rating Uncrewed Systems Technology | June/July 2022 New press-fit marine connectors made with stainless steel and PEEK can cost far less to produce than standard marine connectors (Courtesy of Blue Trail Engineering)