About this reference
What the Blue Water Index shows, and what it cannot know
The Blue Water Index is an independent reference assembled from published open sources. It connects individual hulls, ship classes, bases, systems, future programmes and notable reporting without presenting uncertain conclusions as official fact. Each navy covered here is built from a different kind of source, and that difference is what most of this page is about.
Coverage at a glance
Each navy is covered to its own published scope, and those scopes differ widely. The Chinese fleet here includes its replenishment ships; the American one does not, because US replenishment is run by Military Sealift Command and sits outside the battle-force scope used for that navy. The Russian fleet includes a large corvette and light-frigate force that has no real counterpart in the other three. The British bundle is the broadest relative to its size, counting patrol vessels, mine countermeasures, survey and specialist ships and the Royal Fleet Auxiliary, all categories excluded elsewhere. Read each column against its own scope statement, never as a league table.
Data currency
Each fleet is reviewed on its own cycle, and the table above shows when each was last checked. Future Fleet and reviewed News carry their own review dates on those tabs. Every individual ship record keeps the date on which its own placement was last verified, and for a single ship that date is the one to trust.
How to read a record
Basing confidence
High means direct official or unambiguous named-hull evidence. Medium means a sourced placement with limited corroboration or specificity. Low means weak or unresolved evidence. Assumption is not the bottom of that ladder but a different kind of claim: a probabilistic placement from fleet and class patterns, with no sighting of that hull at that base.
Hull identity
An inferred identity label means the pennant number is documented for the class, but no source assigns that particular hull to the fleet or base shown. Identity and basing are separate axes because a ship can be confidently based while wearing a pennant chosen here, or precisely identified and only loosely placed.
Operational status
What the ship is doing now, recorded only where a dated source states it and left as not publicly documented otherwise. There is no pattern-based guess for status: it changes far too quickly for a pattern to carry information. Presence in the fleet is not a statement about readiness.
What a count means
A hull slot is one ship in commission within that navy’s stated scope. A few slots are aggregate: the fleet is known to hold the ship, but no public pennant identifies which one, so the slot stays visible and nameless rather than being filled with an invented identity or dropped.
Method, task by task
Each task below states the rule that applies everywhere, then how it works out for each navy where they differ.
1. Deciding what is in scope
Each navy has a fixed, stated scope, and a ship is either inside it or absent — nothing is carried at half weight. Ships still building, fitting out or on trials are held in Future Fleet and are never given a fleet or a base before they commission.
2. Identifying the individual hull
The aim is one record per ship, named as the ship is actually known. Where a published name says nothing the class and pennant have not already said, the reference shows the pennant alone rather than dressing a placeholder up as a name.
3. Pennant numbers
A pennant is recorded only where a source publishes it. Where a class’s pennants are published but no source says which hull holds which, the allocation is made here, the record is marked inferred identity, and what could be wrong about it is stated. Where no pennant is published for a ship at all, none is invented — that is fabrication rather than inference — and the slot stays aggregate instead.
4. Fleet and service assignment
The grouping shown beside a ship is permanent, structural metadata: where the ship belongs, not where it is this month.
5. Home port and basing
The map plots berths, not ships. A hull is placed at a base when a source puts it there; where a navy publishes home ports outright, that is simply read off. Where it does not, a placement is derived from documented fleet and formation structure and is labelled an assumption, never a sighting. Where neither is possible, a ship carries no map placement at all: it stays fully present in the fleet listing and in search, because a ship without a published berth is still a ship, and plotting it on a guess would be worse than leaving the map honest.
6. Rating the basing claim
The four tiers are defined above. Two rules matter more than the definitions: the assumption tier is drawn so it can never be mistaken for a sourced observation, and every badge in the application opens to show its own reasoning. Where a navy uses only the highest tier, that is a fact about what its government publishes rather than a compliment to the research.
7. Operational status
Recorded only from a dated source, and left as not publicly documented otherwise. Where a status is shown it carries the date it was established and the source that established it. Forward deployed is a fact about where a ship lives rather than what it is doing, and is shown as its own thing.
8. Class specifications and reference content
Length, displacement, powerplant, speed, range, endurance and complement are held once per class and cited to their own sources, deduplicated so a source shared by many classes is described once. Figures from a consistently measured reference are shown plainly; figures assembled from mixed published sources are marked approximate rather than presented as measured. Systems and aircraft are described once and shared by every class that carries them, and an association is at class level: it does not assert that a particular ship has completed every refit or sails with every item listed.
9. Class artwork and the common scale
Every silhouette on the fleet poster is drawn to one shared scale from the class’s real length, so a carrier genuinely towers over a corvette. Profiles are traced from published recognition drawings wherever one exists; where none does, the class falls back to a generic hull-form shape and is labelled schematic, because an unmarked family shape beside a real profile would read as recognition-grade when it is not. Shape comes from the drawings and size never does — the source sheets state that they are not drawn to relative scale. A concept image is never converted into a purported silhouette of a design that has not been selected.
10. Ships not yet in service
Future Fleet holds programmes from design through sea trials, and nothing there counts toward any in-service total. Build-progress percentages are estimates inferred from the observable build stage and are never reported figures; where the stage is too early or too opaque to judge, the progress reads not estimable rather than showing a plausible-looking number. A placeholder standing in for an unannounced quantity is not a forecast of how many will be built, and programmes since superseded or reported cancelled stay visible, labelled as such, so that older reporting still makes sense.
11. News collection and record linking
Reporting arrives in three separate tiers, and none may be mistaken for another: automatically collected publisher headlines with their own collection time; machine-drafted summaries written only from that cited reporting and labelled unreviewed wherever they appear; and hand-reviewed analysis with written significance judgements. Collection runs automatically twice a day across public feeds in three marked kinds — independent reporting, state media, and a navy’s own official releases. The latter two are evidence of what a government is asserting and are flagged so they are never read as independent observation. A story links to a ship record only on explicit evidence: a pennant beside the name, a naval role word directly adjacent, or an unambiguous class designation. Where a story is filed as a fleet movement, the words that classified it are shown, because a machine judgement that cannot show its working is not one a reader can weigh.
Limitations
- Open-source reporting is incomplete, uneven and can become stale quickly.
- A deployment, shipyard visit or exercise does not always establish a permanent home port.
- Submarine identities and locations are especially opaque in every navy here.
- The map combines named facilities where public reporting does not reliably distinguish adjacent sites, and omits real bases where no ship can honestly be assigned to them.
- Some ships appear with no map placement at all, because no official home port is stated.
- Totals are not comparable between navies; each is covered to its own stated scope.
- Presence in the inventory says nothing about a ship’s readiness or availability.
- Machine-drafted analysis is unreviewed, and is marked as such wherever it appears.
- This reference is independent and is not affiliated with any navy or government.
Contact and corrections
Report a mistake, challenge a source or send a general query. For a correction, include the record concerned and a published source where possible.
Every confidence badge can be opened for its reasoning. Where the evidence does not support a precise answer, the interface is designed to show the uncertainty rather than hide it.