Dropping a torpedo on a submarine has always required getting uncomfortably close to it. The aircraft has to fly to roughly where the submarine is, and a submarine is exactly the sort of thing that objects to being approached. The U.S. Navy now wants a weapon that removes that problem entirely: a torpedo with wings, released tens of thousands of feet up and kilometres away, gliding silently until the last moment.

The programme is called Silent Anvil, and on 25 August the Navy asked industry what it could build.

A torpedo that spends most of its life in the air

The Navy's language is unusually clear about the intent. The weapon, the notice says, will be carried and released from both internal and external weapons stations using standard carriage systems, and will then behave less like a torpedo than like a small glide bomb.

One stated performance goal captures the whole philosophy: maximise time in the air, minimise time in the water. Water is slow, noisy and gives the submarine warning. Air is fast and quiet. Every kilometre the weapon covers as an aircraft is a kilometre the submarine never hears coming.

Inside, the weapon splits into two halves. The torpedo end carries an acoustic sensor, a warhead, a command-and-control section and electric propulsion. The flying end is a wing kit, a radio with its aperture, and guidance and control.

Why the size matters more than the range

The most consequential requirement is not speed or reach. It is the form factor. The Navy wants something shaped roughly like a GBU-39 Small Diameter Bomb and compatible with the BRU-61/A rack, explicitly to maximise the number of manned and unmanned aircraft that can carry it.

That single line reframes the programme. A Mark 54 is a substantial object that only a handful of dedicated platforms can haul. A weapon the size of an SDB can ride in an internal bay, hang off a rack in multiples, and — crucially — be carried by drones. Anti-submarine warfare stops being the exclusive business of large, expensive, scarce maritime patrol aircraft.

The RFI also notes the Air Force could end up using the weapon, and that the design should be open to modification for either service.

This is not the Navy's first winged torpedo

Silent Anvil does not come from nowhere. The P-8A Poseidon already fields HAAWC, the High Altitude Anti-Submarine Warfare Weapon Capability, which bolts a glide kit and wings onto a Mark 54 so the aircraft can release it from high altitude instead of descending to the wave tops. The Navy has declared that capability operational.

What Silent Anvil proposes is the same idea taken to its logical end. Rather than adding wings to an existing torpedo, design the weapon around the glide phase from the start, and shrink it until almost anything can carry it. Industry is being offered both routes: a full integrated weapon, or an unpowered glide wing kit that carries a government-furnished torpedo to the target area.

¿Qué sucede después?

An industry day is scheduled for 17 September, with vendor responses to the RFI due 29 September. The Navy has floated using the Naval Aviation Systems Consortium to award one or more other transaction agreements for the prototyping work — a route chosen for speed rather than ceremony.

None of this guarantees a weapon. Requests for information are the cheapest thing a service can issue, and plenty die quietly. But the requirement being written down matters: the Navy is saying, on paper, that it wants submarine-killing to become something a cheap drone can do from 40,000 feet.

Sources: DefenseScoop, USNI News, Military Times, Stars and Stripes, Inside Defense, and TWZ.