UNOFFICIAL GUIDE · Facts reviewed August 24, 2026 · Game-build data extracted August 17, 2026 (build 24750322) · Example values are per-run and marked as examples
CAMPAIGN MISSION DOSSIER · UNOFFICIAL
IRON NEST Siege of Cartagena Walkthrough: Coastal Batteries
IRON NEST Mission 6, Siege of Cartagena, is a chained-intelligence mission.
Quick Answer
IRON NEST Mission 6, Siege of Cartagena, is a chained-intelligence mission. Locate three concealed installations from spotter reports and destroy them. Take out two armored Vickers 580mm coastal batteries before the Counter Battery Timer ends. Clear eight more enemy units, sound the war horn, and support the breakout with two smoke shells.
Locate three concealed installations from spotter reports and destroy them.
Take out two armored Vickers 580mm coastal batteries before the Counter Battery Timer ends.
Clear eight more enemy units, sound the war horn, and support the breakout with two smoke shells.
Evidence: IN-GAME TEXT mechanics · OBSERVED footage · REPORTED guide steps and observations — see how the labels work.
How to read the evidence labels
Every claim on this page carries a label that says how it was verified:
How to read the evidence labels
Label
What it proves
OFFICIAL
Confirmed by the developer, an official platform, or an official announcement.
IN-GAME TEXT
Read directly from build 24750322 text, or transcribed from in-mission communications where the build was not shown.
OBSERVED
Visible in public footage of the mission.
REPORTED
Described by a guide or community source; the full chain was not visible on screen.
Labels are not interchangeable: a transcription can match the extracted text word for word, but it stays a transcription and does not become an official source.
Mission facts card
Mission facts card
Field
Value
Mission name
Siege of Cartagena (Campaign mission 6)
Hidden installations
Enemy signal station, assembly area, and field command (chained measurements)
Coastal batteries
Two Vickers 580mm batteries, armored
Breakout threshold
8 additional enemy units, then sound the war horn
Ammunition
H/HE for the three installations; AP for the coastal batteries
Medal
Four commendations on offer; conditions on the medals page
Cartagena's garrison remains encircled, its breakout stalled by concealed coastal batteries. Command of the operation passes to Vice Admiral Mendoza.
Siege of Cartagena walkthrough, step by step
The mission is a chain, then a race, then a city clear. First you solve the three concealed installations with chained measurements; then you beat the Counter Battery Timer against two armored coastal batteries; then you destroy eight units, sound the horn, and answer two smoke requests. Each stage has a hard success signal before the next one begins.
Stage 1 — locate and destroy the three concealed installations
Read the full briefing. It sets the rules: the three installations are concealed from aerial photography; two Vickers 580mm coastal batteries are offline and the Counter Battery Timer begins the moment they come online; spotter bearings carry a margin of error of up to 0.5°, and errors compound with each link in the chain.
Mark Iron Nest and all three spotters. Everything in the opening phase is built from those four points.
Locate the enemy signal station from the three spotter distances. The reports converge on a small area; place the marker where the circles agree rather than at the edge of one circle.
Locate the assembly area from the signal station and a spotter bearing. This is the first place an earlier error carries forward, so zoom in before committing.
Locate the field command from the signal station and the assembly area. Check which point each measurement starts from before drawing the line.
Prepare all three firing solutions before loading. Number the markers and the firing cards so a later card cannot be mistaken for an earlier one.
Load H/HE for the three installation shots. AP is for the armored batteries later; do not spend the opening budget on it.
Fire one confirmed solution at a time and read each destruction report before clearing its marker.
The chain must be solved in order. A small error on the signal station moves every point that depends on it, so recheck one stage at a time instead of redrawing everything from Iron Nest.
Stage 2 — destroy both coastal batteries before the timer ends
When the third installation falls, the batteries come online and the Counter Battery Timer starts. The listening post reports their positions with a distance and a direction.
Treat the direction words as search sectors, not exact bearings. A report of "south" or "southeast" defines where to look on the reported radius; confirm the actual battery icon before firing.
Load AP for both batteries and prepare both solutions before committing a volley. Reversed or unloaded cards cost timer time.
Fire the confirmed solutions. Destroying both batteries ends the Counter Battery Timer: Counter-battery threat neutralised.
The timer's exact duration is not published on this page — the build contains no reliable value. The practical rule is to prepare both battery solutions before the first AP shot so the second does not need a mid-timer remeasure.
Stage 3 — eight enemy units and the war horn
Command now orders eight additional enemy units destroyed around the town. That is the breakout threshold; you do not need to clear the whole map.
Destroy eight units, then sound the war horn. If the horn sounds too soon, the mission replies SIGNAL SOUNDED TOO SOON -- ENEMY POSITIONS STILL MANNED.
Remaining enemy icons beyond the eight are not required before the breakout, though they may still count toward kill medals.
Stage 4 — breakout smoke support
Prepare two smoke shells before sounding the horn. Observed runs generated two separate smoke requests during the breakout.
Fire each request at its printed grid as it arrives. The coordinates appear only after the advance begins, so keep the two smoke shells staged rather than pre-calculated.
Wait for Breakout successful. Mendoza authorizes stand down; remaining enemy elements are no longer objectives, and continued fire is optional at your discretion.
Stuck points and troubleshooting
The mission will not progress after I destroyed the coastal batteries
This is a reported issue, not a rule: players reported the mission stalling after destroying both batteries, with no follow-up order, between August 10 and August 21, 2026. This page does not claim the issue is fixed or universal in the current build. What to check first: both batteries show a destruction report, the next order (eight additional units) has actually arrived, and the war horn is only for after the eight kills. If the objective still will not advance on the current build, report it with your build number rather than treating a workaround as a fix.
I sounded the war horn too early
The horn needs the eight-kill threshold first. SIGNAL SOUNDED TOO SOON -- ENEMY POSITIONS STILL MANNED means hostile positions are still manned; finish the eight units, then sound it again.
My shells are not destroying the coastal batteries
Check the loaded shell. H/HE works on the three installations; the coastal batteries are armored (the build lists armour on both), and the consistent multi-source choice is AP. Also check the firing card matches the gun side — reversed left and right cards are a common way to waste the timer.
I am running out of time during the Counter Battery Timer
The timer starts when the batteries come online, and its length is not published here. The recoverable habits are: confirm both battery icons before the first AP shot, prepare both solutions in advance, and use reconnaissance over the coastal strip when the sector is ambiguous. One fan walkthrough describes recovering a damaged run with Emergency Move and two Position Reports; that recovery was not visible in the footage reviewed for this page, so treat it as a described method rather than an observed mechanic.
If you are stuck on another mission instead, the missions hub covers the full mission list and general help.
Coastal batteries, ammunition, and the listening post
Coastal batteries, ammunition, and the listening post
Target
Type
Notes
Coastal Battery 1 and 2
Armored artillery (2★, armour 1)
AP is the consistent multi-source choice; destroying both ends the Counter Battery Timer
Signal station, assembly area, field command
Fortifications (1–3★, start hidden)
Chained from spotter reports; H/HE works
Enemy infantry around the town
Infantry (build spawn config 25)
8 are needed for the breakout; kills count toward medals
Marine garrisons, listening post, spotters
Allied
Do not shoot; killing allies harms Measured Fire Star
The ammunition rule is one-way: H/HE for the three installations, AP for the armored batteries. The battery armour comes from the build data; the exact armour-piercing interaction is not published, so "AP is the reliable choice" is the claim here, not a promise about HE or HCHE damage. For the full ammunition reference, see all shell types.
The listening post is the key to the battery phase. Its audio report gives a distance and a direction from the post. Define the sector on that radius, check the latest reconnaissance over the coastal strip, confirm the actual battery icon, and only then draw the final firing line from Iron Nest. Do not fire at the center of a directional estimate when the icon is findable.
Build-measured punchcard costs (build 24750322): Listening Post 1 RP, Scout Plane 60 RP, Emergency Move 65 RP, Position Report 3 RP. The basic Counter Battery loop is taught in the Counter-Battery mission guide; this page only covers how the loop applies inside Siege of Cartagena.
Medal conditions at a glance
Siege of Cartagena offers four commendations, and the medals page owns the full thresholds:
Measured Fire Star — keep allied casualties at or below the tier threshold.
No Quarter Cross — eliminate enough enemy units in the sector.
Unaided Fire Distinction — destroy targets while requisitioning no aerial reconnaissance.
Austere Service Medal — complete the mission spending no more than the tier's requisition points.
The thresholds are measured from build 24750322; which medal variant belongs to this mission comes from third-party guides, since the build data does not attach medals to missions. See the medals page by-mission section for the full table.
Version and patch notes
This guide is anchored to build 24750322, which maps to Version 1.0 (1622), Patch #5. Siege of Cartagena is a 1.0-era mission: the demo build does not contain it, so demo comparisons are not used here. The softlock reports date from August 10–21, 2026, and this page does not claim a fix. Example coordinates, bearings, ranges, charges, and elevations from any run are per-run values, not universal answers.
FAQ
How do I find the three hidden installations?
Use the chained reports: the signal station is where three spotter distances converge, the assembly area is at the crossing of a bearing from the signal station and a bearing from a spotter, and the field command is at a bearing from the signal station plus a distance from the assembly area. Spotter bearings carry up to 0.5° of error, and each link can carry the previous error forward.
What ammunition do the coastal batteries need?
Armor-piercing. Both coastal batteries are armored in the build data, and AP is the consistent choice across observed runs, community reports, and guides. The exact HE or HCHE interaction is not published, so this page says "use AP" rather than "HE does nothing."
When does the Counter Battery Timer start?
The timer starts the moment the two coastal batteries come online, which follows the destruction of the three installations. The briefing says it directly: "Counter Battery Timer will begin the moment they do." Its exact duration is not published here.
The mission won't progress after I destroyed the coastal batteries — what should I do?
This is a reported issue from August 10–21, 2026, not a confirmed current-build rule. Confirm both batteries show destroyed, check that the eight-unit order has arrived, and only sound the war horn after eight kills. If the objective still stalls, report it with your build number.
Do I need to destroy every enemy in Siege of Cartagena?
No. The breakout needs eight additional enemy units destroyed, then the war horn. Remaining icons are not required before the breakout, and after Breakout successful the leftover enemies are no longer objectives at all.
How many smoke shells do I need for the breakout?
Prepare two. Every run reviewed for this page generated two separate smoke requests, and the mission text warns to prepare smoke shells before the advance. If a run asks for a third coordinate, load it on request rather than buying a full stack in advance.
What medals does Siege of Cartagena offer?
Four commendations: Measured Fire Star, No Quarter Cross, Unaided Fire Distinction, and Austere Service Medal. Full thresholds live on the medals page; this page gives the mission-level summary only.
Sources and version notes
Reviewed August 24, 2026. Evidence types and dates are stated beside each claim above.
Official: one developer design statement in the official Discord (July 16, 2026, pre-release); used here as a design note, not a current-build behavior contract.
In-game text: briefing, comm messages, entity registry, shell values, medal definitions and punchcard costs extracted from the 1.0 game build (build 24750322) via the shared game-data extraction (August 2026); matching mission communications transcribed by a third-party mission database and a fan walkthrough (retrieved August 23, 2026; build not stated).
Observed footage: two release-era player runs (August 9, 2026), used as transcription and cross-check; no build number displayed.
Reported: dated community questions and bug threads in the official Discord (August 2026), including the softlock reports.