r/WeirdWeapons

Bit of an oddball.

those tank turrets looks cool

Manta Ray is an American underwater drone designed to sleep on the ocean floor for months, and that radical choice might make it the most strategically important machine nobody is talking about right now.

The vehicle moves without a propeller — it changes its own weight to sink and rise, converting that motion into forward travel, which means its energy draw is almost zero for most of the mission.

It was shipped across the country in five standard containers and bolted together on a dock in two days, a deployment model that quietly rewrites every assumption about how you get a large underwater asset into position fast.

With the Navy accelerating procurement of rival systems and the Pentagon funding at least three competing design teams, Manta Ray's silence since early 2024 is either the most suspicious pause in undersea robotics — or the calm before something significant.

The glider’s whole trick is refusing to spin a propeller

Manta Ray is a glider, and gliders have been in the water since the 1960s doing survey work for the Navy and NOAA. The mechanism is old and mildly counterintuitive.

Rather than turning a propeller, the vehicle changes its own weight. It pumps seawater in to get heavy and sink, pumps it back out to get light and rise, and the wings convert all that vertical falling into forward travel. Brian Theobald, chief engineer for Manta Ray at Northrop Grumman, has described the propulsion as “falling forward [with purpose] through the water all the time,” going up as well as down.

The American drone crossed 2,700 miles inside five shipping containers, gets bolted together on a dock in two days, swims out by pumping seawater through itself instead of turning a propeller, then anchors to the ocean floor and sleeps there until someone wakes it

SHIPPING FOOTPRINT

5 containers

The whole vehicle travels as subsections in five standard shipping containers and gets assembled at the destination.

LAST PUBLIC TEST

Feb–Mar 2024

Full-scale in-water testing off Southern California. No further milestone announced since DARPA’s May 2024 release.

FUNDED

NAVY XLUUV LINE

$1.13 billion

16 vehicles through FY2031, starting with two Boeing Orcas at $135.8 million in FY2027.