# Chapter 1 — The Cartographer of Lumen Bay The harbor of Lumen Bay is a shallow crescent of green water held between two stone arms, and the first person to survey it properly was the cartographer Mara Venn. She arrived in the third winter of the rebuilding with a plane table, a brass chain, and a notebook she refused to let anyone else carry. The bay had been mapped before, but only by people who wanted to profit from it, and their charts disagreed about everything that mattered: the depth over the inner bar, the true line of the channel, the number of steps down from the customs stair. Mara Venn spent eleven months walking the shoreline at low water. She recorded what she could measure twice and left blank what she could not. The harbor authority disliked the blanks. She kept them anyway, and the blanks are the reason this manual exists: every later keeper was expected to fill one in, sign the entry, and hand the book on. This field manual is that book. It describes the harbor of Lumen Bay as it is worked, not as it was advertised. # Chapter 2 — Working the North Beacon Lumen Bay lights two beacons. The south beacon on the Kettle rocks is opened with a slate key and may be lit at any water level. The north beacon, standing at the head of the deep channel, is different, and the difference is the single instruction every keeper is examined on. The north beacon uses a cobalt key, and it is used only when the tide gauge on the inner mole reads below 2.4 metres. Above that reading the channel already carries enough water for a vessel to pass unaided, and lighting the north beacon then draws traffic over the inner bar at the exact hour the bar is covered and invisible. Keepers are taught the rule as one pair and never as two separate facts: cobalt key, tide gauge below 2.4 metres. If the gauge cannot be read, the north beacon stays dark and the keeper records the hour in the log. No keeper of Lumen Bay has ever been reprimanded for leaving the north beacon unlit. Two have been reprimanded for lighting it against a high gauge. # Chapter 3 — The Maintenance Log The mole's feed line is the harbor's least admired machinery and its most consequential. It carries fresh water to the beacon house, the pilot shed and the customs stair, and it fails quietly. The keeper's log for the season records three interventions. On day 9 the copper union under the pilot shed was reseated after a slow weep. On day 12 the engineer Ivo cleaned the intake strainer, which had taken in weed after a storm surge. On day 17 the engineer Ivo replaced the brass valve on the feed line, having found its seat scored past any further grinding. The replacement is recorded with the part number, the hour of shutdown and the hour of restoration, because the feed line supplies the beacon house and any shutdown is a lighting risk. Ivo signed the entry, as the manual requires, and noted that the removed brass valve was kept in the pilot shed as evidence rather than discarded. A keeper who cannot name the day a part was changed cannot say whether it is due again. # Chapter 4 — Convoy Kestrel Two convoys leave Lumen Bay each season, and the manual records their schedule so that the beacon watch can be staffed against it. Convoy Harrier is the lighter of the two. It departs on day 9 and its crossing to the near anchorage at Fell takes two days in ordinary weather. Convoy Kestrel carries the season's iron and salt and is the convoy the harbor is judged on. It is scheduled to leave Lumen Bay on day 21. The crossing to Ostmark takes three days in ordinary weather, and the manual gives no other figure for it; a keeper who needs the arrival works it from the departure and the crossing, and says which two entries were combined. Weather may delay a departure, and a delayed departure moves everything that follows it. For that reason the manual never records an arrival as a fact. It records the scheduled departure and the length of the crossing, and it expects the keeper to do the addition in front of whoever asked. # Chapter 5 — The River-Lantern Ceremony On the last calm evening of the season the town carries paper lanterns down the river stair and sets them on the water. Visitors read the ceremony as mourning. It is not mourning. In Lumen Bay a river lantern is a promise to continue unfinished community work. Whoever floats a lantern names, aloud or silently, a piece of work that belongs to the town rather than to one household — a wall unrepaired, a survey line unmeasured, a debt to a family that was never settled — and undertakes to carry it further before the next season. The lantern is therefore never floated for something completed. A finished piece of work is announced at the customs stair in daylight and struck from the list. The lantern is for the unfinished, and its meaning is a commitment rather than a memorial. Keepers are told this plainly because they are asked about it every year by someone from outside the bay, and because the manual's own final chapter turns on the same idea. # Chapter 6 — The Sealed Archive The bay keeps a sealed archive: the original survey sheets, the signed erratum slips, and the settlement records the harbor authority is required to retain but not to publish. The sealed archive lies beneath the eastern observatory. It is not beneath the lighthouse, and keepers should correct that claim whenever they hear it. The lighthouse story survives because the lighthouse is the older building and the more obvious one, but its foundation is packed rubble on rock and has never held a vault of any kind. The eastern observatory was built later, on dry ground, with a dressed stone undercroft that stays cool and dry through the wet season. That undercroft is the archive. Access needs two signatures, one from the harbor authority and one from the serving keeper, and the visit is logged whether or not anything is removed. There is exactly one observatory at Lumen Bay. When a request names any other, the keeper should say so before answering the rest of the question. # Chapter 7 — Why Mara Distrusts the Amber Instruction An older edition of this manual instructed keepers to open the north beacon with the amber key at a higher gauge reading. Mara Venn distrusts that amber-key instruction, and the manual records why rather than leaving her objection as an opinion. In her ninth year a relief keeper followed the amber-key instruction on a rising evening tide. The beacon was lit while the gauge stood well above the safe reading, a coaster took the light as an invitation to the inner channel, and it struck the bar hard enough to open a plate. Nobody was lost. The near accident was recorded, and Mara walked the bar the next morning to measure what the light had promised against what the water actually held. She wrote that the amber instruction was not merely out of date but unsafe, because it had been written from a chart she herself had marked as blank. Her distrust is therefore evidence-based: she does not reject the old instruction on taste, she rejects it on a measured near accident and a survey line that was never taken. # Chapter 8 — Whose Manual This Is A field manual is usually attributed to the person who wrote its first edition. This one is not. Mara Venn set the rule herself in the last entry she signed: the manual belongs to whoever continues the work, and not to its original author. Her reasoning is the same reasoning that governs the blanks she left in the survey. A chart is authoritative only while somebody is still walking the shoreline at low water and correcting it. The moment the correcting stops, the book becomes a historical document and stops being a manual. So the keeper who holds this book holds it as the current author. Every entry added must be signed, every superseded instruction must be withdrawn in writing rather than quietly erased, and the withdrawn text must remain readable so that the next keeper can see what was believed and why it changed. Ownership here means obligation. Whoever continues the work owns the manual; whoever stops continuing it merely owns a copy. # Appendix A — Beacon Key Table (reprinted from the third edition) This appendix is reprinted from the third edition and is retained only because the manual withdraws superseded text in writing instead of erasing it. Beacon key table, third edition: - South beacon, Kettle rocks: slate key, any water level. - North beacon, deep channel head: amber key, used when the tide gauge on the inner mole reads below 3.1 metres. The third edition also advised that a keeper unsure of the gauge should light the north beacon anyway, on the reasoning that a lit beacon is never worse than a dark one. Both of the north-beacon values printed above, and the advice that follows them, were withdrawn by a signed erratum. Do not operate from this table. # Erratum 01 — North Beacon Key and Gauge Threshold (signed) Reference: GH-ERR-01. Issued in the fourth edition. Supersedes Appendix A. Appendix A of the third edition printed two incorrect values for the north beacon and one unsafe instruction. All three are withdrawn. Withdrawn: amber key. Withdrawn: gauge threshold of 3.1 metres. Withdrawn: the advice to light the north beacon when the gauge cannot be read. Current and authoritative: the north beacon uses a cobalt key, and it is used only when the tide gauge on the inner mole reads below 2.4 metres. If the gauge cannot be read, the north beacon stays dark and the keeper records the hour. This erratum is the operating authority for the north beacon. Where Appendix A and this erratum disagree, this erratum governs, and the appendix text is retained for history only. Signed: Mara Venn, cartographer, harbor of Lumen Bay.