Page 13: of Marine Technology Magazine (November 2024)

“Everything is very simple in War, but the simplest thing For years, lithium-ion (Li-ion) batteries have been the is dif? cult.” standard for UUVs of all sizes (as well as some crewed

Writing nearly 200 years ago, Prussian general and military submarines and submersibles). Their high energy density, theorist Carl Von Clausewitz understood the tendency for scalability, low maintenance, and relative safety make them unpredictable or uncontrollable factors to disrupt, degrade, or attractive to defense and commercial customers alike. But even completely derail the most meticulously planned warfare Li-ion dominance may be peaking, as hydrogen fuel cell operations. While Clausewitz was speaking of 19th century power has been making steady gains. Fuel cells, which gen- land warfare, his words still ring true today, particularly in erate electricity by combining hydrogen and oxygen through the undersea domain, where navigation, communication, and an electro chemical reaction, have for many years enabled endurance can be the source of myriad operational challenges, conventional (non-nuclear) crewed submarines to operate both anticipated and unforeseen. for weeks at a time without surfacing. In addition to having

Endurance is one of the most critical elements of undersea a higher energy density than Li-ion batteries, fuel cells do dominance. Admiral Hyman Rickover, the father of the not self-discharge during periods of inactivity, which could nuclear navy, understood this, and it is still the case today, greatly extend uncrewed underwater operations and enable seventy years after the USS Nautilus put to sea. But for nu- missions involving prepositioned systems in forward areas. clear-powered submarines, with their nearly unlimited energy The Teledyne Seabed Supercharger and the Solus family supply, endurance is largely a human endeavor, limited only of UUVs from Cellula Robotics are examples of systems by food stores and crew morale. Uncrewed underwater sys- utilizing fuel cell power. And recently, Connecticut-based tems, while they may have no need for calories, are, however, In? nity Fuel Cell and Hydrogen was awarded a contract voracious consumers of a different kind of stored energy – to provide the U.S. Navy with UUV fuel cell technology, kilowatt-hours. And ensuring that they are properly nourished possibly for use in the Navy’s prototype Snakehead large- is one of the enduring challenges of uncrewed underwater op- displacement UUV (LDUUV).

erations. Nuclear-powered underwater systems are also on the draw- www.marinetechnologynews.com 13

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