{"id":19206,"date":"2026-09-04T11:00:34","date_gmt":"2026-09-04T15:00:34","guid":{"rendered":"https:\/\/www.autonocion.com\/us\/?p=19206"},"modified":"2026-09-04T06:43:56","modified_gmt":"2026-09-04T10:43:56","slug":"23-foot-drone-submarine-pipe-truck-money","status":"publish","type":"post","link":"https:\/\/www.autonocion.com\/us\/23-foot-drone-submarine-pipe-truck-money\/","title":{"rendered":"A 23-foot Danish drone submarine built out of a length of 20-inch fiberglass pipe carries 660 pounds, about what the warhead of a Mk 48 torpedo weighs, and that weapon needs a submarine with people in it to go anywhere. This one costs pickup truck money"},"content":{"rendered":"

Defense startups keep finding strange places to build underwater drones. We’ve covered a Philadelphia company assembling 425-pound drone submarines in a former marble showroom<\/a>, and a Rhode Island plant tooled up to turn out 200 three-ton hulls a year<\/a>. Apparently Denmark looked at all of that and decided the bar for unlikely submarine builders could go a little lower.<\/p>\n

S\u00f8ens Tech is a small Danish mechatronics outfit whose day job is building electronics for horizontal directional drilling. If that term means nothing to you, HDD is the trenchless technique crews use to push pipe and cable under rivers, harbors and highways instead of digging them open. In August, the same company turned up at DALO Industry Days<\/a>, Scandinavia’s largest defense trade show, with a 23-foot (7-meter) drone submarine called the Shadowfin CORE. The show ran August 19 and 20 at the MCH Messecenter in Herning, and the machine sitting on the stand was, from the looks of things, a length of industrial pipe with thrusters.<\/p>\n

That is pretty much what it is, and that is the entire pitch.<\/p>\n

So what is the Shadowfin, exactly?<\/h2>\n

Naval News filmed the drone at the show, and Ukrainian defense outlet Defense Express, working from that footage, reports the hull is a standard 500-millimeter (about 20-inch) fiberglass pipe. Defense analyst H I Sutton, who runs Covert Shores, published his assessment of the design<\/a> on September 3 and estimates the rest: 23 feet long, roughly 1.5 tons (about 3,300 pounds) in the water, and a payload around 660 pounds (300 kilograms). Covert Shores puts the price near \u20ac50,000, which is about $58,000 at current exchange rates.<\/p>\n

That is nicely optioned pickup truck money.<\/p>\n

For context, that 660-pound payload lands right next to the roughly 650 pounds of explosive packed into a Mk 48, the heavyweight torpedo the US Navy runs, and that weapon needs a multibillion-dollar submarine to get anywhere. Sutton describes the Danish design as “geared to the expendable nature of modern drone warfare,” and the parts list backs him up. The hull comes from an industrial catalog. The two pumpjets are commercial units, apparently built by Copenhagen Subsea. S\u00f8ens Tech itself pitches the machine as “engineered for cost-asymmetric naval warfare,” which is defense-brochure language for cheap enough to lose.<\/p>\n

\n
\n
Length<\/div>\n
23 ft<\/div>\n
7 meters of hull on a 20-inch (500 mm) fiberglass pipe. Covert Shores estimate.<\/div>\n<\/div>\n
\n
Displacement<\/div>\n
1.5 tons<\/div>\n
About 3,300 pounds, with a payload around 660 lb (300 kg). Covert Shores estimate.<\/div>\n<\/div>\n
\n
Price<\/div>\n
~$58,000<\/div>\n
Around \u20ac50,000 per Covert Shores. Two commercial rim-drive pumpjets, off-the-shelf parts.<\/div>\n<\/div>\n
\n
TARGET<\/div>\n
First delivery<\/div>\n
Ukraine, 2026<\/div>\n
First unit expected for field trials later this year, per Covert Shores.<\/div>\n<\/div>\n<\/div>\n

Before you take those numbers to the bank, I should flag something. S\u00f8ens Tech has not published a spec sheet, so every figure above is Covert Shores’ estimate, and the depth rating, range and endurance are anyone’s guess right now. A fiberglass pipe hull almost certainly limits how deep this thing can go, and Sutton says as much. I’d frankly be surprised if it strays far below periscope depth.<\/p>\n

There is no propeller shaft on this thing<\/h2>\n

The thrusters are arguably the most interesting hardware on the boat. Shadowfin uses two rim-drive pumpjets, a layout where the blades attach to a spinning ring instead of a central hub. Passing current through the rim turns the ring directly, so the drivetrain sheds its gearbox and drive shaft along with the seals that usually fail first. Fewer spinning parts also tends to mean less noise, which matters a great deal when your whole job is not being heard. You can buy this kind of thruster commercially today, and Sutton notes it has barely shown up in defense projects so far.<\/p>\n

Everything else on the machine follows the same buy-it-cheap logic, with one clear exception: the electronics, which happen to be the one thing a drilling-tech company is actually good at. A fixed mast on top holds cameras, sensors and communications antennas. S\u00f8ens Tech says the drone navigates with an inertial navigation system paired with a Doppler velocity log, and if you want the bar version of that, GPS signals can’t reach underwater, so the vehicle tracks its own motion against the seabed and does the math from there. When it surfaces, encrypted satellite and LTE links handle data and command. The company has also floated a version with a short snorkel mast feeding a combustion engine inside the hull, which would stretch endurance well past what batteries allow. HDD, remember, is a business of steering unmanned hardware through places nobody can see, and a drone submarine asks for pretty much the same skill set.<\/p>\n

The Enhanced version wants to carry a torpedo<\/h2>\n

The base model handles surveillance and reconnaissance in shallow water, and S\u00f8ens Tech markets it as an anti-submarine picket too, either parked as a forward sensor node or pinging away as an acoustic decoy. The company’s stated ambition for a follow-on version, the Shadowfin Enhanced, is to carry and fire a lightweight torpedo like the MU90.<\/p>\n

Denmark does not use the MU90. Sutton points out the weapon has been sold to Ukraine for its future Ada-class corvettes, and he sketches a formation where cheap Shadowfins draw a submarine’s attention while the armed ones sit back and shoot. I’d treat the torpedo talk as a roadmap rather than a product, though, because nothing has been fired from this hull yet. The machine that exists today is the unarmed CORE, in the water, on camera.<\/p>\n

Ukraine gets the first one<\/h2>\n

S\u00f8ens Tech posted sea trial photos from Danish waters on its own site in mid-August, days before the Herning show. Defense Express headlined the drone as an underwater strike platform at the price of a Shahed, aimed at Russian ships, ports and bridges, and reported the first unit goes to Ukraine for field trials once the Danish trials wrap. Sutton expects that delivery later this year.<\/p>\n

So a $58,000 pipe with thrusters now sits in the same conversation as the marble-showroom submarine from South Philadelphia and the 200-a-year factory in Rhode Island, and it is almost certainly the cheapest of the three. The same Herning show also had a German seabed drone shaped like a penguin<\/a> on display, which tells you what kind of trade fair Denmark hosts these days.<\/p>\n

H I Sutton published his Covert Shores assessment on September 3, 2026, two weeks after the Shadowfin CORE went on display in Herning, and the first unit is expected in Ukraine before the year is out.<\/p>\n

Image Credit: Naval News Youtube Channel<\/a><\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Defense startups keep finding strange places to build underwater drones. We’ve covered a Philadelphia company assembling 425-pound drone submarines in … <\/p>\n

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