A SeaBreather vessel under way at speed, dark hull with azure trim throwing spray, an industrial coastline low behind it

Aquatic Prosperity Vessels

A treatment plant that can reach the water that needs it.

Fixed plant treats whatever is piped to it. A bay will not be piped anywhere. So the plant goes to sea, and every constraint on this page follows from that one decision.

An Aquatic Prosperity Vessel is a working boat built around what it carries: an intake, gas preparation, a closed reactor, an outlet, and the instruments that govern all four. The designation is ours. The flag, the survey and the manning are entirely ordinary.

The physics of why the treatment works belongs to the platform, and SeaBreather sets it out properly. What follows is the operator's half of it: what sits on the deck, and what constrains which hull can work which water.

The deck, item by item

None of these is exotic on its own. The engineering is in getting the whole set onto a hull that can still hold station in a two-meter sea.

  1. The intake A coarse bar-rack that keeps large animals and debris out, a low approach velocity, and a draw depth set to the layer that has actually failed, chosen off the profile taken on arrival. Inside a contracted zone, certain areas are mapped as places no water is taken from at all.
  2. Gas preparation Ozone is generated on board and consumed inside the pass that called for it, so none is ever stored, and that is what keeps the stage ordinary to permit. What the reactor is fed is made up for the duty in front of it, blend and rate both set on the day.
  3. The contained reactor Where the treatment happens, inside the hull. Gas is sheared into the sub-micron range in line with the flow, the water takes what the duty calls for, and none of it is in contact with the bay while any of that is going on. None of it stops moving either. There is no storage on this deck.
  4. The outlet Treated water returned to the water it was drawn from, at the layer that lost its oxygen. On a stratified estuary in August, that means below the thermocline. Putting the effluent into the warm skin of a capped column leaves the failed layer exactly as it was.
  5. The instrument set Profiling through depth for dissolved oxygen, temperature, salinity, pH and turbidity, plus sampling points on the water going in and the water going out. Read either side, at the same depths, every pass.
  6. The log Position, time, draw depth, throughput, the duty the reactor ran, and the assays either side of it. Each entry is made during the pass it describes. An inspector will reach for this file before anything else we have written, so it is treated as the product.
  7. Endurance Fuel, gas, crew hours and hull time. Replenishment for all four is designed into the zone before the first pass, with the berth, the supplier and the interval named.

The first of those is the one a technical reviewer goes at hardest, and rightly. Nineteen thousand liters a minute is an intake before it is anything else, so the question of what happens to eggs and larvae arrives early and gets four engineering answers: the bar-rack, the low approach velocity, the selectable draw depth and the areas inside a zone where nothing is taken at all. A large animal at the rack is one of the conditions that halts the work outright. What the intake would do in your particular water is assessed at the site read and written into the scope with its exclusion areas named.

What decides the tier

Vessels come in three tiers — Nimble, Standard and Mega. Which one suits a zone is settled by physical constraints long before anybody discusses budget, and the constraints usually disagree with each other.

Constraints that decide which SeaBreather tier can work a zone
Constraint What it settles
Draft over the shallowest working ground The hard ceiling, and the one that usually decides it.
Transit time from a usable berth How much of a working day is treatment and how much is passage.
Endurance between resupply Whether a hull works to a schedule or to a supply chain.
Deck area and power How much generation and oxidation capacity physically fits.
Sea state and crew rotation How many days in a working year are genuinely on the water.

Two of those deserve expanding. Shallow ground beats every other consideration on the list — a reef flat or a lagoon entrance rules out a bigger hull whatever the budget says, and a far corner of a zone first reached at noon is a corner that gets treated badly every week the program runs. Endurance is the other one, and it is the reason the tier table has a ceiling. Past a certain zone size it stops being a question of what a single hull can absorb between passes and becomes a question of the configuration on the water, which is the next section.

Which tier suits which kind of water is tabulated on the platform's own site. This table is the other half of that question: what stops a tier from working a zone even when the water looks right for it.

Super SeaBreather

Past a certain zone size, the answer stops being a bigger hull and starts being a second one.

A vessel that has to break off and steam to a replenishment berth is a vessel not treating anything for the duration. On a small zone that is an inconvenience. On a national program it is the difference between a fleet and a rota.

The Super SeaBreather configuration answers it by working as a pair, so the treating hull stays on station and in the zone instead of spending its day in passage. A program at that size is also where an industrial gas partner with regional supply stops sitting at the end of a purchase order and becomes part of how the program is built. Which commercial shape that takes — direct delivery by Alarivean, a joint venture, a license from Sophia Delta — is settled program by program. What never changes is that the systems are run as a service rather than sold or rented.

The pairing is a way of deploying the same hulls, and the treatment stage aboard each of them is the one described on the treatment page.

A Super SeaBreather and its second hull under way over thin pale water on a Red Sea approach, low buildings on the shore ahead
A visualization of the pairing. What it shows correctly is the water: pale, thin, over sand and reef, which is where draft starts making the decisions.

Specifications and the permit

A permit, a regulator, and the craft it allows in the water.

Two throughput figures appear below. They belong to two different boats, and reading them together produces nonsense.

A SeaBreather hull is specified at approximately 5,000 gallons per minute of contained throughput — about 19,000 liters a minute. One capacity covers both duties: the flow that goes through the reactor is the same flow that leaves oxygen-enriched, into the water it was drawn from. It is a rate. Nothing is stored on the deck, so the hull is never carrying your water anywhere, and the discharge a permit governs is the same flow the intake took a moment earlier. That is the number a contract carries, and the calibration phase measures it on your own water against parameters written down before a hull moves. Anything specific to a named bay arrives after the site read, in writing, with its assumptions attached.

The other figure belongs to a different craft entirely. Florida's Department of Environmental Protection issued permit FLOA00062 in September 2024 for a red tide mitigation trial, on a five-year window that opens only when live Karenia brevis exceeds 100,000 cells per liter. The boat named in it is a modified personal watercraft producing ozonated seawater at 1,000 to 2,000 gallons a minute — a fraction of the displacement and a fraction of the throughput of anything described further up this page. The Sarasota Bay Estuary Program and the nonprofit START each wrote up the grant on their own sites.

So a state regulator examined the proposal and allowed a bounded trial in its own water. Proving the same thing across a bay is the work after that, and the estuary program has asked to be the body monitoring it. The documents behind a program are listed in one place.

~5,000 Gallons per minute of contained throughput specified for a SeaBreather hull, about 19,000 liters a minute — a single capacity that both treats and oxygenates, verified on the client's own water during the calibration phase Alarivean vessel specification, stated by the operator
1,000–2,000 Gallons per minute of ozonated seawater from the craft permitted for the Florida red tide field trial — a modified personal watercraft, a much smaller boat than any SeaBreather. The permit was written up independently by the estuary program and by START Sarasota Bay Estuary Program, 2024
FLOA00062 Florida DEP permit issued September 2024 under Chapter 403, a five-year window conditioned on active Karenia brevis above 100,000 cells per liter START — mobile system to attack red tide

Asked by harbormasters and naval architects

Three about the hull

What does APV stand for?

Aquatic Prosperity Vessel. The name is ours; no registry uses it.

It is shorthand for a working boat carrying a treatment plant as payload. Flag, survey and manning follow the ordinary rules for a vessel of that size in that water, and no part of this arrangement asks a maritime authority to invent a category.

What throughput does a hull contract to?

Approximately 5,000 gallons per minute per vessel — about 19,000 liters a minute — of contained throughput. A single capacity, treating and oxygenating on one pass: the flow that gets treated is the flow that leaves oxygen-enriched.

That is the specification a contract carries, and the calibration phase measures it on your water against parameters set down in writing beforehand. A result that misses those parameters closes the phase. A figure for a named bay follows the site read, never precedes it.

Will a hull actually be there when the water turns?

That is the whole of what a subscription is buying. Hulls, gas supply and accredited crew are held against your zone continuously, so a forecast changes the tasking order for the week and nothing else.

Coverage is confirmed at the site read and written into the agreement before anything is committed. The other route is to call once the water has already turned, and then a fleet has to be found, moved and accredited in a hurry — which takes longer than a bloom takes to close a beach, and is charged accordingly wherever anyone offers it at all.

A wave curling over in cold light, the lip beginning to throw forward

Draft, distance, exposure

Send us a chart and a month.

Bathymetry, the nearest working berth and the months your exposure peaks in are enough to say which tier would work that zone through a year, and whether one hull carries it or the honest answer is a fleet.