What the game is
The Harbour Manifest is a fleet-finding mystery — the classic solitaire battleships puzzle, rebuilt as a detective case. A tip-off names a bonded warehouse on the midnight quay: goods stolen across the city are hidden somewhere among its crates, in caches of one to four crates laid in straight lines. The night watchman walked the floor and counted the disturbed crates in every row and column; his log is your only map.
The tip-off inventory tells you exactly what is hidden — how many single crates, two-crate chests, three-crate runs and four-crate long cases — and the watch has already verified a handful of bays for you. Tap a bay once to mark a crate, twice to cross it out as clear floor, three times to clear the mark — or press and drag along a row or column to paint a whole run in one stroke. When a cache's crates are all marked and nothing presses against it, it is prised open and its contents join the evidence board. Recover the whole floor, and the goods themselves point at one shipper's paperwork.
Case procedure
- Empty the zero lines first. A tally of 0 means nothing in that line was touched — cross the whole line out and enjoy it. Lines whose tallies are already met by your marks settle the same way.
- Look for lines with no slack. When a line has exactly as many open bays as crates still missing from its tally, every one of those bays is a crate.
- Cast shadows from every crate. No two caches touch, not even corner to corner — so every diagonal neighbour of a marked crate is clear floor, and a completed cache clears everything around it. This one rule settles more bays than any other.
- Mind the run limits. A row of marked crates can never grow longer than the largest cache still unfound. When the four-crate long case is accounted for, no remaining run may reach four.
- Work one line at a time. Lay out every legal way a line's remaining crates can sit — respecting your crosses and the cache sizes still missing — and keep whatever falls the same way in every arrangement. This is the quiet workhorse of the whole floor.
- Hunt the big cache. The largest outstanding cache needs a long, clean berth, and there are rarely many left. If every remaining berth passes through the same bays, those bays hold cargo wherever it lies.
- Read the haul against the manifests. Clear every shipper whose same-size entry differs from a recovered consignment. When one manifest accounts for everything, accuse.
The rulings that matter most
- Caches are straight lines. Every cache is a single row or column of crates — never bent, never scattered.
- No two caches touch. Not side by side and not corner to corner. A bay diagonal to a crate is always clear floor.
- Tallies count crates, not caches. A row tally of 4 might be one long case, or a run of three and a single with clear floor between.
- Verified bays are settled. Solid bays were confirmed as crates by the watch and dotted or stamped bays as clear floor — they cannot be changed and never lie.
- Crosses are never required. A cache is recovered when its crates are marked and nothing presses against it; crosses are your working notes and can be wrong without penalty.
- Consignments travel by crate size. All caches of one size hold one kind of goods. A shipper whose entry for that size names different goods cannot account for the consignment — and is cleared.
- No consignment convicts alone. Every case is built so each consignment leaves at least two shippers standing — the warrant always needs the whole haul.
- Decoy entries prove nothing. At higher ranks manifests carry entries — ports of origin, wax seals — that no consignment speaks to. They neither clear nor condemn anyone.
Choosing a rank
Dock Clerk (6×6 floor, ten crates, four shippers) teaches the spacing law in about ten minutes, with generous verified bays and manifests different enough to read at a glance. Customs Officer (8×8, sixteen crates, six shippers) is the full method: fewer verified bays, overlapping manifests and one decoy entry in every ledger. Harbour Master (10×10, the classic full fleet of twenty crates, eight shippers) is the long shift — a floor that rewards patient counting, and paperwork where only combinations of consignments single out the culprit. Bigger floors add more interlocking deduction, never unfair steps.
Fairness, hints and reveal
Every case is generated and then proved before you see it. The generator's solver must complete the whole floor using only the deductions described in this manual — the same reasoning you use at the desk — which guarantees exactly one arrangement fits the log and that no guessing is ever required. When a layout needs more help, the watch verifies another bay before the case ships; when it needs too much, the layout is thrown away. The detective layer passes the same standard: the consignments identify exactly one shipper, and removing any single consignment would leave at least two. Check flags marks that cannot be right without adding any of its own. Hints escalate politely: the first press names a deduction and the reasoning behind it; a second press points at the exact bay, and the mark is still yours to place. Reveal unseals the watchman's own chart and excludes the case from your cases-cracked tally. Wrong accusations are stamped on the file; the case stays open.
Printing a case
Any case can be downloaded as a PDF pack built entirely in your browser from the same case number as the on-screen floor: the briefing and every shipper's manifest on the case sheet, one full floor plan with tallies, verified bays and the tip-off inventory sized for pencil work, and an optional answer key showing the watchman's chart, the recovered consignments and the warrant. Battleships grids are a natural fit for paper — a pack runs about three A4 sheets and suits classrooms, puzzle clubs and long train journeys, and the case number on the cover reopens the same floor on screen.
Questions from the quay
What is The Harbour Manifest?
The Harbour Manifest is a fleet-finding mystery — the classic solitaire battleships puzzle rebuilt as a detective case. Stolen goods are hidden among the crates of a bonded warehouse in caches of one to four crates. The night watchman’s log counts the disturbed crates in every row and column of the floor, and pure deduction pins every cache without disturbing honest cargo. Each recovered cache names its goods, and reading the full haul against the shippers’ declared manifests condemns exactly one smuggler.
How do the watchman’s tallies work?
The number beside each row and above each column counts the crates hidden in that line. The tip-off inventory tells you the whole fleet of caches from the start — how many single crates, two-crate chests, three-crate runs and four-crate long cases are hidden — and a handful of bays come already verified by the watch. A line whose tally is met is finished; a line with exactly as many open bays as missing crates fills itself. Everything else follows from the caches’ shapes and spacing.
Why can no two caches touch?
A smuggler spaces their hiding places so that one unlucky discovery cannot unravel the rest — so no two caches ever touch, not even corner to corner. This is the rule that does the most work on the floor: the moment you mark a crate, every diagonal neighbour of it is guaranteed clear floor, and a completed cache clears its whole perimeter. If you remember one ruling, make it this one.
How do the recovered goods catch the smuggler?
Every cache size forms one consignment: all the three-crate runs hold one kind of goods, all the singles another, and so on. Each shipper’s manifest declares one entry per crate size. A shipper whose declared entry differs from a recovered consignment of that size could not have hidden it — their paperwork cannot account for it, and they are cleared. Only one manifest accounts for every recovered consignment, entry for entry, and every case is built so that no single consignment convicts on its own.
Is every floor guaranteed solvable without guessing?
Yes. Every floor is proved before you see it: the generator’s solver must complete the whole plan using only named, human deductions — met tallies, forced fills, the no-touch rule, run limits, single-line arrangement sweeps and berth hunting for the largest cache. If a floor would ever require a guess, the generator adds another verified bay from the watch or rejects the layout and builds a new one. The detective layer is proved the same way: the consignments identify exactly one shipper, and removing any one would leave at least two.
What do Check, Hint and Reveal do?
Check flags any current mark that cannot be right, without adding marks of its own — it is always safe, and it is also your safety net on the no-touch rule. Hints come in two strengths: the first press names a deduction and explains the reasoning that makes it — which line to work, or which rule applies; pressing again points at the exact bay, though the mark is still yours to place. Reveal unseals the watchman’s own chart, and a revealed case never joins your cases-cracked tally.
What are the case ranks?
Dock Clerk hides ten crates in a 6×6 floor against four clearly different manifests — a whole case in about ten minutes, with generous verified bays. Customs Officer works an 8×8 floor against six overlapping manifests padded with a decoy entry no consignment addresses. Harbour Master is the full assignment: a 10×10 floor, the classic full fleet, eight manifests and two decoy entries, where only combinations of consignments identify the culprit.
Can I play on a phone?
Yes. The floor plan sizes itself to the screen and every bay is a proper button — tap once to mark a crate, twice to cross the bay out as clear floor, three times to clear the mark, or press and drag along a row or column to paint a whole run in one stroke. A stroke only overwrites bays in the same state as the one it started on, so painting crates never destroys your crosses, and Undo takes back the whole stroke. Your marks save automatically between visits, and each case has a case number so the same floor can be reopened.
Can I print a case?
Yes. Any case can be downloaded as a PDF pack built entirely in your browser from the same case number as the on-screen floor: the briefing and every shipper’s manifest on the case sheet, one full floor plan with tallies and verified bays sized for pencil work, and an optional answer key showing the watchman’s chart, the recovered consignments and the warrant. Nothing is uploaded anywhere, and the dialog shows the sheet count before you download.
Is The Harbour Manifest free?
Yes. All ranks are free to play in your browser with no account or sign-up. A new case is one click away, and every case is generated fresh — the fleet is placed, proved fair, and dressed with new goods, shippers and paperwork, so no two nights on the quay read the same.