Sea · Undersea and surface systems

The one domain where
the network is guaranteed to fail

Seawater attenuates RF at roughly 1,400 dB per kilometre. There is no cloud under water. Every vehicle down there is, for most of its life, alone — so we built four systems that are designed to be alone.

4 systems · 1 domain XLUUV · MUSV · EFFECTOR · GRID LEVIATHAN XLUUV-1

The sea domain thesis

Revenant — the autonomy OS

01 · Alone by default

Useful undersea communication is acoustic. That means 2.4 kbps at 8 km on a good day, 200 bps at 30 km on a normal one, a five-second one-way latency, and a channel that changes with the tide. There is no mesh to lean on and no cloud to fall back to.

This is why REVENANT CORE is a sea product before it is an air product. An autonomy runtime that degrades toward a cloud is useless at 400 m. A runtime that degrades toward itself is the only thing that works down there. Every system on this page carries the entire mission model, the ROE engine and the world model on board, and none of them need permission to keep working.

02 · Legally crowded

An aircraft over a battlefield is a military object in a military place. A 190-tonne autonomous submersible transits the exclusive economic zones of countries that have agreed to nothing, an unmanned surface vessel shares a traffic separation scheme with merchant traffic, and an autonomous undersea effector sits on a seabed under a shipping lane for six months.

The engineering is solvable. What has actually kept these systems out of the water is that nobody could answer a lawyer. REVENANT LEDGER is the answer: every observation, classification, human authorization and engagement decision is hash-chained and signed at the edge, and it is exportable, replayable and admissible. In this domain that is not a feature. It is load-bearing structure.

03 · Port-independent

A shipyard is a coordinate. There are eleven yards in the United States that can handle an extra-large uncrewed undersea vehicle and an adversary's targeteer can list all eleven on one page.

LEVIATHAN goes into the water at any commercial pier with six metres of depth, forty metres of quay wall, eleven people, and one crane rated 30 t — because no single lift in its entire assembly sequence exceeds 29.4 t. STYX sorties from any pier or well deck under its own power. In a Pacific fight, the hull that can be assembled inside the theatre after the shooting starts is worth more than the better hull that has to be sailed in from Newport.

The sea arsenal

FORGE-1 — where they are built
In development Leviathan 68 ft, 190 t, 6,500 nm. It goes in the water at a fishing pier, not a drydock. Detail design Styx An arsenal ship, not an attack craft. It launches and recovers aircraft at sea, so the magazine regenerates. Design Deadfall 180 days dormant at 105 mW. It cannot arm without a signed authorization, and it expires on a date certain. In development Tidewall Attributes a cable intrusion to a hull, not to a noise. The product is not detection — it is admissible proof.

Four numbers that define the domain

29.4t Heaviest single lift in LEVIATHAN's entire assembly and launch sequence. No drydock, no crane over 30 t.
46.2m² STYX clear mission deck. Enough to land, service, re-arm and relaunch a BANSHEE in nine minutes in sea state 4.
105mW DEADFALL-M measured dormant draw against a <2 W requirement. 180 days on 454 Wh.
10m TIDEWALL along-cable position accuracy on first detection — from optical time-of-flight, with no triangulation.

Why these four, and not four others

Government & Primes

Request a sea domain briefing

Classified and unclassified briefings on LEVIATHAN, STYX, DEADFALL and TIDEWALL are available to US government customers, allied ministries of defence, and commercial submarine-cable operators.

Request a briefing programs@fantom.aero

Every figure on the sea domain pages is a design target derived from first-principles analysis, not a trial result. Where a number is an estimate, we say so on the product page. No export-controlled information is published on this site.