{"id":17326,"date":"2026-08-16T17:00:27","date_gmt":"2026-08-16T21:00:27","guid":{"rendered":"https:\/\/www.autonocion.com\/us\/?p=17326"},"modified":"2026-08-15T19:23:10","modified_gmt":"2026-08-15T23:23:10","slug":"swedish-robot-torpedo-tube-tows-drone","status":"publish","type":"post","link":"https:\/\/www.autonocion.com\/us\/swedish-robot-torpedo-tube-tows-drone\/","title":{"rendered":"A 661-pound Swedish drone fires out of a submarine’s torpedo tube, crawls across the Baltic floor at 3 knots, picks up a second one that has been sitting there waiting and tows it back in through the same hole"},"content":{"rendered":"

The US Navy has spent the past 18 months taking victory laps over underwater drones that can get back inside a submarine. First came the announcement, in May 2025, that USS Delaware had launched and recovered a drone through its torpedo tube on a real forward-deployed mission. Then came 2026, with a contract for the Iver4 900<\/a>, a second contract for a rival system, and the reveal that some of this had been running at sea before anyone said a word in public.<\/p>\n

We covered every step, because the recovery half genuinely is the hard half. Firing things out of a torpedo tube is a solved, century-old problem. Convincing a submerged submarine to take something back is not.<\/p>\n

Sweden watched all of it the way you’d watch a neighbor celebrate discovering the dishwasher. The Swedish Navy has operated a tube-launched robot called SUBROV since 2019, when the country’s defense procurement agency, FMV, handed the first unit<\/a> to the crews of the submarines Gotland and S\u00f6dermanland.<\/p>\n

And the Swedish machine skipped a grade. It leaves through the standard 21-inch tube, does manual labor in front of the boat with a set of swappable arms, and when one of Saab’s AUV62 drones finishes its own mission, SUBROV collects it off the seabed and brings it home through that same opening. A robot, launched like a torpedo, whose job description includes rescuing other robots.<\/p>\n

A 661-pound handyman that lives in a torpedo tube<\/h2>\n

The Saab design is built around one constraint: everything has to fit the hole a heavyweight torpedo uses. The vehicle runs 10.2 feet long (3.1 meters), weighs 661 pounds (300 kg) and carries up to 22 pounds (10 kg) of payload. Top speed is 3 knots, endurance is six hours, and it works down to 1,640 feet (500 meters), with a range of 6.2 miles (10 km).<\/p>\n

\n
\n
In service<\/div>\n
2019<\/div>\n
Handed by FMV to the crews of the Gotland and S\u00f6dermanland. Six years before the US Navy’s first operational tube recovery.<\/div>\n<\/div>\n
\n
The machine<\/div>\n
661 lb<\/div>\n
10.2 feet long, plastic shell, swappable arms and sonars. Six hours per sortie at up to 3 knots.<\/div>\n<\/div>\n
\n
Working depth<\/div>\n
1,640 ft<\/div>\n
500 meters. Deep enough, per Naval News, to reach any point on the Baltic floor.<\/div>\n<\/div>\n
\n
A26<\/div>\n
The next door<\/div>\n
59 in<\/div>\n
The Multi-Mission Portal on the A26 submarine, reported at roughly 1.5 meters wide. Sweden and Poland both have boats on order.<\/div>\n<\/div>\n<\/div>\n

Nobody is winning a race at 3 knots. The point is that it shows up with tools. The payload menu covers manipulator arms, sonars and communication buoys, so the same vehicle can photograph a suspected mine on one sortie and do physical work outside the hull on the next.<\/p>\n

The system splits in two. The wet half rides inside the torpedo tube, a dry control console stays with the crew, and the robot flies on a cable that streams video and sonar back in real time. Saab also offers a battery pack for running it untethered. Naval News flagged the practical benefit of the wire years ago: the data comes up the cable, so nothing gets broadcast into the water for someone else’s hydrophones to enjoy.<\/p>\n

The feature Swedish officials leaned on hardest was the boring one. The whole system gets handled like a heavyweight torpedo, on the same racks and loading gear, so any submarine with a 21-inch tube can carry it without modification. Anders Svensson, FMV’s product manager for underwater weapons at the time, described the mission this way: “One can, among other things, inspect and one can salvage other smaller vessels and bring them to the submarine while remaining hidden under the surface.”<\/p>\n

Its best trick is towing other robots home<\/h2>\n

He meant the salvage part literally. The demo video FMV released back then shows the full sequence: SUBROV swims out, finds a drone waiting on the seabed, grabs on and ferries it back to the tube.<\/p>\n

The drone in question is the AUV62<\/a>, and Saab shaped it like a heavyweight torpedo on purpose, with the same mechanical and electrical hookups, so a submarine can treat it like ammunition. The mine-hunting version carries a synthetic aperture sonar and maps the bottom on its own for hours. It can hit 20 knots when it wants to, per Saab’s spec sheets over the years, and it still ends its day parked on the seabed waiting for a 3-knot tow truck.<\/p>\n

H I Sutton, who tracks this niche at Covert Shores, has described the choreography: the submarine settles on the bottom, the AUV62 parks itself on the seabed in front of it, and SUBROV goes out and gathers the thing like a valet. No divers, no surfacing, no surface ship loitering overhead to give the game away.<\/p>\n

As late as November 2024, the assessment in the trade press, citing Naval News, was that no other navy on Earth had an operational way of bringing torpedo-shaped drones back inside a submarine. Sweden did, and had for five years.<\/p>\n

The Americans have since closed the gap their own way, and it’s worth being precise about the difference. The 2025 USS Delaware milestone was the first untethered drone recovered through a tube on a forward-deployed tactical mission, a machine flying itself back into the opening with no pilot and no cable. The Razorbacks now riding on allied submarines<\/a> park themselves. SUBROV gets driven. One approach is a self-parking car, the other is a tow truck, and both end with a drone inside a submarine that never showed itself.<\/p>\n

The Baltic is a workshop with terrible lighting<\/h2>\n

Geography explains why Sweden got here first. The Baltic averages about 197 feet (60 meters) of depth, and its floor holds the leftovers of the twentieth century: mines laid in two world wars<\/a>, plus a modern layer of power cables, data cables and pipelines that keeps making the news for the wrong reasons.<\/p>\n

A 500-meter working depth covers all of it. Sutton made that point in a Naval News analysis<\/a> written weeks after the Nord Stream blasts: SUBROV can inspect infrastructure at depths that reach anywhere in the Baltic, and a submarine doing that work has one advantage no surface ship can copy. Nobody knows it’s there.<\/p>\n

Swedish boats are built for the floor, too. Saab advertises bottoming as a feature of the A26, whose hull carries no external tanks, so the submarine can sit on the seabed and wait. Park the boat, park the drone in front of it, send out the robot with arms. The whole doctrine treats the bottom as a place you work, not a place you avoid.<\/p>\n

Poland bought the grown-up version in June<\/h2>\n

On June 29, in the port city of Gdynia and with both countries’ prime ministers in the room, Poland signed for three of Saab’s A26 Blekinge-class submarines, Defense News reported<\/a>: $4.8 billion (SEK 47 billion) covering the boats, weapons, training and support, with the first hull due in 2031 and the last by 2038.<\/p>\n

The A26 is what happens when the SUBROV idea gets an architecture instead of a workaround. Between its four 21-inch torpedo tubes sits the Multi-Mission Portal, an oversized lock reported at roughly 5 feet across and 20 feet long (1.5 by 6 meters), sized for divers and for underwater vehicles no torpedo tube could swallow. Saab has not published the portal’s internal clearance, but it has published the robot meant to use it: the Autonomous Ocean Drone<\/a>, a 23-foot (7-meter), 7.2-ton machine whose first sea trials were targeted for the middle of this year.<\/p>\n

Sweden’s own two boats, HMS Blekinge and HMS Sk\u00e5ne, are still in build, with deliveries slipping to 2031 and 2033 after an October 2025 renegotiation. Poland is bridging the wait by leasing the Swedish submarine HMS S\u00f6dermanland, and Polish crews start training in Sweden this month, per trade reporting around the signing.<\/p>\n

Which closes a loop worth noticing. S\u00f6dermanland was one of the two boats whose crews received the very first SUBROV in 2019. The submarine Poland is borrowing to learn the trade is one of the ones that taught the torpedo tube to work in reverse.<\/p>\n

Plumbing stops making headlines once it works<\/h2>\n

Saab barely mentions SUBROV these days. Its underwater announcements in 2026 have been about bigger robots, NATO networking projects and a $4.8 billion order book, and a 2019 tool that does its job doesn’t need a press cycle.<\/p>\n

But every navy that matters is now converging on the same door. The Americans got there by teaching drones to thread a 21-inch opening on their own. The Swedes got there by giving a robot arms and a tow job seven years ago, then moving on to building a bigger door. Either way, the torpedo tube’s century as a one-way street is over \u2014 and the first lane running in the other direction had Swedish plates.<\/p>\n","protected":false},"excerpt":{"rendered":"

The US Navy has spent the past 18 months taking victory laps over underwater drones that can get back inside … <\/p>\n

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