OpenFront v0.35 Nations Naval Doctrine: When Nations Send Warships at You and Where the 300/500-Route Cap Changes Your Decisions

OpenFront v0.35 gave nations a naval doctrine, and it changes when an ocean crossing is safe, how much a blockade is worth, and how hard piracy actually is. The short answer: on Hard a nation answers a blockade with a fleet the same size as yours and will not sail a boat route longer than 300 tiles; on Impossible it sends one warship more than you are holding and pushes routes to 500 tiles. Read the retaliation percentages, the route cap, and the cost ladder before you commit gold, and check your own game with the verification tool at the end.

What changed in v0.35 and what stayed the same

The warship unit itself is largely unchanged from v0.34. It still patrols an assigned water tile, attacks un-allied enemy warships and transport ships within its detection range, retreats toward one of its owner’s ports when it drops below 75 percent of maximum health, and recovers passively near a friendly port. The base numbers carry over: 1,000 maximum health, a 250-point base shell damage roll, a 130-tile detection radius, a 100-tile patrol range, and a 20-tick shell cooldown. What v0.35.0 added is not a new unit but a new layer of intelligence around the unit, all of it on the nations side. The tag source adds three things that did not exist in v0.34.25. First, clearSeaLane, the behavior where a nation detects a fleet blocking its boats and sends a warship squad at the blocker. Second, maxBoatRoute, the function that caps how long a nation will let a boat route be, at 300 tiles on Hard and 500 on Impossible. Third, the boat-routing gate in the AI attack behavior, which makes nations route their boats around your warships instead of straight through. The v0.35.0 release notes state the intent plainly: nations “route boats around warships, send warship squads at blockades, and don’t sail past 300/500 tiles.” That single line is the doctrine, and every decision in this guide follows from it. If you are playing v0.34 or earlier, none of the new behaviors apply and the old naval stalemate and blockade guide remains the correct reference for how to read a lane; the version boundary matters because the numbers below only describe v0.35.0 and later. It is worth being precise about what the boundary means in practice. The tag source at v0.34.25 contains no clearSeaLane and no maxBoatRoute symbol at all, so a v0.34 nation never sends a matched squad at your blockade and never applies the route cap to its own boats; the doctrine is therefore a clean addition, not a tuning change, and you will not see partial versions of it. The one thing that looks like it changed but did not is the warship’s own behavior: patrol, detect, attack, retreat and heal are all carried over from v0.34, so a warship you already know how to place still behaves the same at the unit level, and only the nation’s decisions around your ships are new. That distinction keeps the guide honest about scope. Everything the doctrine adds lives in the nation’s execution code, not in the unit config, which means the unit numbers in the section that follows are the stable part you can trust across v0.35 minor versions, while the retaliation percentages and the route cap are the version-sensitive part you should re-verify if you jump across tags. Hold that split in mind as you read: unit constants first, doctrine numbers second, and treat any discrepancy you see in your own lobby as a version signal rather than a bug.

The direct answer and the decision framework

If you want one framework: a warship is a lane controller, not a free weapon, and in v0.35 the lane controller is now being matched by the AI. Before you commit to buying, pirating, or blocking, run four checks. Check one: what is your boat route length to the target, measured in tiles, because if it is under the nation’s 300 or 500 cap the nation will commit a full invasion push and if it is over the cap the push is weaker. Check two: what is the difficulty, because the retaliation chance and the anti-blockade response are both keyed to it. Check three: how many warships are you holding the lane with, because on Hard the nation sends as many as you have and on Impossible one more. Check four: can you afford the cost ladder, because the next warship is 250,000 gold times the count plus one, capped at 1,000,000, so the third and later ships are the expensive ones. When those four checks line up you have a defensible lane; when they do not, you are holding a blockade the AI is specifically built to break. The rest of this guide turns each check into a concrete number and a concrete move, and it links to the warship fleet decisions guide for how to place and manage the ships themselves and to the warship veterancy guide for how stripes and repair capacity change the math. One thing the framework deliberately leaves out is the question of which lane to hold at all, because that is a separate decision about map shape and enemy value rather than about the doctrine, and the four checks only make sense once you have a lane in hand. The order of the checks is not accidental. The route-length check comes first because it is the only one that can remove an entire option before you spend a single gold: if the lane is so long that the nation’s own logic and yours both sit under the cap, the nation is fully committed and the math is the worst case for the side doing the blocking. The difficulty check comes second because it sets the retaliation probability and the anti-blockade multiplier, and a wrong difficulty assumption silently inflates how safe you think a lane is. The warship-count check is third because it is the one that changes live: the nation’s count in the lane moves every time a retaliation coin flip lands or an anti-blockade squad departs, so this is the check you re-run continuously rather than once. The cost check is last because it is the budget constraint that the other three feed into, and it is where the doctrine is most punishing, since the cost ladder means your fourth ship costs the same as your third, which is 1,000,000 gold, while the nation can match you with ships it built at the cheap end of the same ladder. Run the four checks in that order, and if any one of them says no, stop and rethink the lane before the others even run.

The numbers that drive the doctrine

Every decision in v0.35 naval play reduces to a small set of constants, so here they are with their source location. The cost ladder is min(1,000,000, (n+1) * 250,000), which means the first warship is 250,000 gold, the second is 500,000, the third is 750,000, and every ship from the fourth onward costs the 1,000,000 cap. That is the single most important number in the doctrine, because it is why a three-ship blockade is disproportionately expensive and why nations on Hard choose to match you one-for-one rather than simply outbuy you. The warship’s base health is 1,000 and the base shell damage is 250 per shot on a 20-tick cooldown, so a single warship fires a 250-damage shell every two seconds in the game’s timing. Detection is 130 tiles and patrol is 100 tiles, which means a warship sees enemies well before it is inside its own patrol ring, and that gap is where the AI’s routing gate gets a head start on you. Auto-retreat triggers at 75 percent of maximum health, and passive healing is 1 health point per tick within 150 tiles of a friendly port, which is 10 health per second at the game’s 100-millisecond tick and does not stack across multiple ports. Veterancy caps at level 3 with a 20 percent increase to both maximum health and shell damage per level, so a level-three warship carries 1,600 health and rolls 300 base damage. These are the v0.35.2 values and they are the ones the guide uses; the community warship guide on Reddit agrees with all of them except the shell damage spread, which it lists as 200 to 300 and which reflects the per-shot variance around the 250 base rather than a different base value. A few of these numbers interact in ways that are easy to miss. The detection radius being larger than the patrol range means a warship can see and begin engaging an enemy up to 30 tiles before it is even inside its own patrol ring, which is why a warship sitting still at its patrol tile is still dangerous well beyond the tile you assigned it. The 20-tick cooldown against a 250 base damage and a 1,000-health target means a single unassisted warship takes four clean shots to kill an unveteraned warship, or eight shots if the target has retreated and is healing, so a one-versus-one at full health is a slow affair unless one side is at a veterancy or position advantage. The 1,000,000 cost cap is not just a ceiling, it is the reason the doctrine works at all: because the nation and you both pay the same capped price for the later ships, the nation can afford to match your fleet one-for-one on Hard, whereas if the ladder kept rising it would instead choose to ignore a lane it could not cheaply contest. The 75 percent retreat threshold matters more than it looks, because a warship that has taken a few hits and is at 74 percent will abandon an otherwise winning patrol and sail for port, which is exactly the moment a nation squad can peel it off, and that interaction is the retreat-trap failure mode later in this guide. Treat the retreat threshold and the heal ring as a pair, because the ship only becomes safe when it is inside 150 tiles of a port, and the gap between the two is where the fight is won or lost.

The route cap and why it reshapes an ocean crossing

The new behavior with the widest reach is maxBoatRoute, which returns 300 tiles on Hard and 500 tiles on Impossible. It is called from the boat-routing gate in the AI attack behavior, and it answers the question of how far a nation is willing to push a boat-based operation. Below the cap, the nation treats the route as a viable full push and will commit its transport and boat logic toward the landing. Above the cap, the nation refuses to sail the full route and the operation degrades: the push is smaller, slower, or abandoned, because the AI will not sustain a long, unshielded boat line past the limit. This is the same mechanic the v0.35.0 release notes describe as nations “not sailing past 300/500 tiles.” For you as the player it cuts both ways. When you are the attacker crossing an open ocean, a target that sits 320 tiles from the nearest reachable coast on a Hard game means the defending nation’s own reinforcements and counter-pushes are capped by the same 300-tile rule, so your window of exposure is shorter than it would be if the route were 250 tiles. When you are the defender, a hostile port that is 400 tiles out on Hard is safe from a full boat push but still reachable by a single well-timed transport that stays under the cap. The transport landings guide covers how to choose a reachable coast and cap each wave; the route cap is the number that tells you whether the nation will even answer with a full response, so measure the lane first and only then size the operation. On Medium and below there is no route cap in the same form, which is why the cap only bites on Hard and Impossible and why the difficulty check in the framework above comes before the range check. The cap is also the reason the doctrine is asymmetric in a specific way that the release notes do not spell out. The function returns a distance, and that distance is applied to the nation’s own boat logic, so it limits how far the nation is willing to send boats, and by the same function it limits how far its counter-pushes reach when you are the one crossing. You, as the player, are not bound by the cap at all, because you control your own transport lines directly, which means the cap is a ceiling on the AI, not on you. That asymmetry is the entire play space of the v0.35 ocean: you can operate a long route that the AI cannot fully answer, but you can only do so safely if you understand that the AI’s inability to push a full response is a ceiling on its reinforcements, not a guarantee that nothing is coming, because a single transport that stays under the cap can still land. Measure in tiles, not in screen distance, because the game’s tile grid is what the function uses and the on-screen pixels do not map one-to-one to it, especially on zoomed-out large maps where a long ocean lane looks short. If you are crossing and the lane is over the cap, the real risk is not the nation’s main push, it is the well-timed small landing that slips under the limit, and that is the failure mode the staging counter is built to handle.

Scenario A: crossing an open ocean lane under a warship screen

Assume a Hard game, an FFA map with a wide ocean between your home island and a rich target island, and a hostile nation that has placed a two-ship warship screen in the middle of the lane. Your boat route to the target measures 280 tiles, which is under the 300-tile Hard cap, so the nation is willing to commit a full response. The screen is holding the lane with two warships, and because you are under the route cap the nation can reinforce that screen and route boats around it using the new gate. The correct read is that a straight transport push through the middle is a bad trade: you will be meeting a two-ship screen that the AI is actively re-anchoring, and your own transport route is short enough that the AI’s own boat logic does not hesitate. The two sound plays are both lateral. First, buy the lane with a warship of your own and force the doctrine’s anti-blockade rule to fire on you instead: on Hard clearSeaLane sends the nation as many warships as you are holding, so if you hold the lane with one ship the nation answers with one and if you hold it with two it answers with two, which converts a passive screen into a symmetric fight you can choose the place and time of. Second, split the route: send a small beachhead first that keeps each individual boat line under the cap, land it, then push the follow-up by land exactly as the v0.35 nations do to you. The assumption that makes this fail is sending the whole fleet in one column past the screen; the assumption that makes it work is treating the screen as a price, not a wall, and paying it either in matched warships or in a shorter, staged route. The third option, which the doctrine does not explicitly reward but which the route cap makes possible, is to change what you are crossing for at all. If the target island is worth crossing for, the question is not whether you can beat the screen but whether the lane is the cheapest lane to it, and on a wide-ocean map there is usually a longer, emptier lane and a shorter, guarded one. The guarded lane triggers the anti-blockade squad, the empty lane sits over the route cap, and the cap is on the AI, not you, so the empty lane is the one where your long transport line meets no matched fleet. The trade is time: a longer route exposes your fleet for more of its crossing, and the window in which the defending nation can send a single well-timed transport that stays under the cap is wider. That is why the staged beachhead is the default: it converts a long, exposed, single-wave crossing into a short, held, follow-up push, and it is the move the v0.35 nations themselves use against you, which is the cleanest evidence that it is the intended answer. If you are on Impossible rather than Hard, change one variable: the anti-blockade squad sends one warship more than you hold, so holding the lane with two ships draws three from the nation, and the symmetric fight becomes a fight you lose one-for-one, which pushes the decision firmly toward the staged, cap-under route rather than the matched-warship one.

Scenario B: running a piracy economy against a hostile trade lane

Assume a Hard game where you have one port on a strait that a rich nation uses for trade, and you want to convert that trade into income. A warship is the only unit that captures enemy trade ships, and the doctrine changes the cost of that capture. The moment you capture the nation’s trade or transport, the game updates the relation by minus 7.5 for a trade ship or minus 15 for a transport, and on Hard the nation then has a 50 percent chance to build a warship directly against you, on Impossible an 80 percent chance, and the cap is ten warships after which it only moves an existing one. So piracy is no longer a free income stream: each successful capture is a coin flip that can add a warship to the screen you are operating against. The doctrine’s anti-blockade rule compounds this, because once the nation fields warships in that water it will send a squad at any of your warships that it reads as blocking its boats, matching your fleet on Hard and sending one more on Impossible. The correct play is to make the lane cheap to defend. Keep the number of warships you hold the strait with low, so that when the retaliation and the anti-blockade squad both fire you are not being out-manned; time your captures to the nation’s low-attention windows rather than into an active warship screen; and let the distance-based payout do the work, because the community piracy guide shows the gold-per-minute peak near 378 tiles of travel, meaning a capture near the end of a long voyage is the most valuable one you can make. The embargo timing and trade control guide is the economy-side reference for when to cut or hold a lane; this scenario is the warship-side cost of doing exactly that in a game where the AI now answers with matched steel. The numbers that make the decision are the relation penalties and the retaliation cap, and they matter more than the gold itself. A minus 7.5 hit from a trade capture is small, but a minus 15 hit from a transport capture is half the distance to a war declaration in the game’s relation scale, and because retaliation fires on the same event that drops the relation, a single transport capture on Impossible is an 80 percent chance to add a warship to the screen you are operating against. That is the compounding the scenario is about: each capture does not just take the ship’s gold, it can grow the fleet you have to fight next turn. The ten-warship cap is the only thing that stops the spiral, and it is worth internalizing, because once the nation has built ten warships against you it stops building new ones and only moves its existing fleet, which means a piracy lane that has already drawn ten ships is no longer getting more steel, and the fight becomes a matter of where those ten are rather than how many are coming. The practical read is to treat the first five captures as the expensive ones and the later ones as the cheap ones, and to time your biggest captures to the moment the nation is at its cap, when the retaliation chance still exists but the cap means no new ship can answer. The distance-based payout from the community piracy guide is the other half of the equation: a capture near the end of a long voyage is worth more gold, so the optimal piracy economy is a long lane with few warships you hold it with, which is exactly the configuration the anti-blockade rule penalizes, and that tension is why the scenario has to balance the lane’s length against the fleet’s size rather than maximizing either one alone.

What fails and the counter to each failure

The doctrine produces four recurring failure modes, and each has a specific counter rather than a general one. Failure one is the over-blocked lane: you hold a blockade with three warships on Hard, and clearSeaLane sends the nation three of its own, so you have spent 1.5 million gold across the ladder to hold a lane the AI now matches at equal cost. The counter is to hold lanes with one ship when possible, because a one-ship lane only draws a one-ship answer and the ladder cost stays at the cheap end. Failure two is the over-long route: you plan a boat push across a 400-tile lane on Hard, the nation’s 300-tile cap does not stop your own operation but it does tell you the nation will not send a full counter-push, and you read that as safety when it actually means the fight is one-sided in a different direction and you are exposed to a well-timed single transport. The counter is to stage the crossing into lines that each sit under the cap and land a beachhead first. Failure three is the piracy spiral: you capture trade, the relation drops by 7.5 to 15, the retaliation coin flip lands, and within a minute a new warship is built on your strait. The counter is to cap the warships you hold the strait with and to stop capturing the instant the nation is fielding warships there, because the income is not worth an escalating steel race. Failure four is the retreat trap: you let a warship drop below 75 percent in open water far from a port, it turns to retreat, and the nation’s squad, which only targets patrolling warships with no hostiles on their patrol tile, peels it off before it reaches the 150-tile heal ring. The counter is to keep at least one friendly port within 150 tiles of every patrol you run, so the passive 10-health-per-second heal can actually reach the ship before it is picked apart. There is a fifth failure mode that is subtler and that the doctrine’s matching rule creates rather than the unit numbers. It is the matched-fleet deadlock: you hold a lane with two warships, the nation answers with two on Hard, and now neither side wants to be the one that spends the next 1,000,000 gold to outmatch, so the lane freezes into a stalemate that costs you gold every turn you hold it in the form of the patrol upkeep and the opportunity cost of ships that could be doing something else. The doctrine was designed to produce exactly this: by making the nation match your fleet at the capped price, it makes the lane a war of attrition in gold rather than a quick tactical fight, and the player who starts the blockade is the one who pays the upkeep while waiting for the nation to flinch. The counter is the same as the framework’s first check, which is to decide whether the lane is worth a gold attrition war before you commit, and to set an exit condition, such as a specific relation drop or a specific target capture, at which the blockade stops being worth the upkeep. It is also the reason the doctrine rewards the lateral moves in Scenario A so heavily: a matched-fleet deadlock is the worst-case outcome of the matched-warship option, and it is the outcome the staged, cap-under route is specifically built to avoid. The five failure modes together are the full list of ways the v0.35 doctrine turns a naval decision against you, and each one has a counter that is a specific move rather than a general principle, which is the point of the doctrine: it is a list of traps with known exits, and the skill is in recognizing which trap the current lane is before you spend the gold that the trap was built to collect.

Mode and map adjustments

The doctrine’s numbers are the same in every mode, but the decisions they imply differ by difficulty and by map shape. By difficulty, the only settings that matter are the two that are difficulty-keyed: the route cap and the retaliation and anti-blockade chance. On Easy the nation never retaliates with a warship and clearSeaLane does nothing, so the whole doctrine is inert and you can run blockades and piracy the old way. On Medium the nation retaliates with a 15 percent chance but still does not send anti-blockade squads and does not apply the route cap the same way, so piracy is cheap but blockades are safe. On Hard everything switches on at once: 50 percent retaliation, a matching anti-blockade squad, and the 300-tile cap, which is why Hard is the difficulty where you must run all four checks in the framework. On Impossible the doctrine is at full strength: 80 percent retaliation, an anti-blockade squad that sends one warship more than you hold, and the 500-tile cap, which means the lane can be longer but the answer is bigger. By map shape, wide-ocean maps with a single choke strait are where piracy and blocking pay off, because one warship holds a narrow lane; branching or lake maps with many short water lanes are where the route cap bites, because most lanes sit under 300 tiles and the nation is always willing to push. The nations pressure guide covers how nations apply pressure on a runaway FFA leader, which is the third v0.35 naval behavior and the one that makes holding the longest lane in an FFA the most dangerous move in the game. Within each difficulty the map shape then decides how much of the doctrine you will actually feel. On a tight lake map where every water lane is under 200 tiles, the route cap never engages and the whole of the doctrine reduces to the retaliation chance and the anti-blockade squad, so the difficulty check is almost the only one that matters and piracy is the dominant naval activity. On a wide-ocean map the reverse is true: most lanes sit near or over the cap, the route length check dominates, and the doctrine plays out as a question of which side can stage a crossing under the limit rather than a question of whether a blockade will be answered. On a branching map with several short straits and one long open lane, the doctrine is mixed, and the correct read is that the short straits are piracy and blockade territory while the long lane is a staging-and-crossing territory, and trying to run one naval strategy across the whole map is the error the branching map is designed to punish. The mode also interacts with the doctrine in a way that is not obvious from the numbers: in FFA the nations do not ally against you, so a warship screen you build is only contested by the one nation that owns the lane, which is why FFA is where the doctrine is most legible and easiest to learn, and in team or alliance modes the nations can coordinate, so a screen you build may draw matched fleets from two or more nations at once, which pushes the effective fleet size up faster than the one-nation math in this guide predicts and is the single biggest reason the same lane that is safe in FFA is dangerous in an alliance lobby. Treat the guide’s one-nation numbers as the FFA baseline and add a nation to the count for every additional allied nation that owns part of the lane you are holding.

The original decision table

This table is the whole doctrine compressed into a lookup you can use mid-game. For every situation, it gives the number that decides it and the move that follows. The rows are the four checks from the framework plus the two failure counters, and the columns separate Hard from Impossible because those are the two difficulties where the doctrine is active. Use it to decide the lane before you spend gold, and re-check it the moment the nation’s warship count in the lane changes, because that is the variable that changes the row. The table is deliberately conservative where the doctrine is not: the Easy and Medium rows are omitted because the doctrine is inert or half-inert there, and the two columns that remain are the only ones where every cell is an active, versioned number. A few of the rows deserve a sentence of their own before you trust them. The route row is the one to read first, because it is the gate that decides whether the rest of the table even applies to your lane. The retaliation row is the one to re-run most often, because it is the row that changes live as the nation builds ships. The cap row and the cost row are the two budget constraints, and the safe-lane row is the move that falls out of them. If you are unsure which row to trust when two of them seem to point at different moves, the route row wins, because a lane that is over the cap changes the entire premise of the fight and no amount of matched warships fixes a route the doctrine does not want to be fought on. The table is also the place to put your own numbers: when you verify the doctrine in your own lobby, write the observed retaliation rate and the observed squad size back into the Hard and Impossible columns, because the difference between the table’s expected value and your observed value is the most reliable signal of which version you are actually playing, and the whole guide is built on the assumption that you are on v0.35.0 or later.

How to verify the doctrine in your own game

None of this should be taken on faith, so here is a way to confirm the numbers in your own lobby before you commit gold. First, confirm the version: the doctrine only applies in v0.35.0 and later, and the clean check is the warship counter-behavior, because v0.34.25 has no clearSeaLane at all, so if a nation sends a matched squad at your blockade you are on v0.35 or newer. Second, confirm the route cap by measuring a boat route: place a transport line to a target more than 300 tiles away on Hard and watch whether the nation’s own boat push against you stays weak while your short routes get full answers; the asymmetry is the cap working. Third, confirm the retaliation chance over a sample: capture a handful of the same nation’s trade ships on Hard and count how often a new warship appears near your lane, because a 50 percent rate over ten captures should land roughly five new ships, and a visibly different rate means you are on a different difficulty. Fourth, confirm the heal ring by running a warship to 75 percent health near a port: it should stop retreating the moment it is within 150 tiles of the port and start ticking back up at 10 health per second, and it should not stack if two ports are in range at once. If any of those four checks fails, the game is not behaving like v0.35.2 and the numbers in this guide do not apply to that build, which is exactly why the verification step is part of the doctrine and not an afterthought. Keep the first match guide handy for the early-game economic setup that has to exist before a warship is even affordable. The four checks are ordered so that the cheap ones run first and the expensive ones last, because the point of verification is to confirm the version with the least gold at risk. The first check, the counter-behavior check, is free and runs passively: you do not have to build anything, you only have to watch whether a nation ever sends a matched squad at a blockade, and the presence of that squad is the single cleanest version signal, because no v0.34 build has the symbol at all. The second check, the route-cap check, costs one transport line and a measurement, and it is the second-most reliable signal because the cap is a hard function with a fixed return and it shows up as a visible asymmetry between your short routes and the nation’s long ones. The third check, the retaliation sample, is the one that costs the most gold and the most time, because you have to run a handful of captures and count the outcomes, and it is also the noisiest signal, because a 50 percent chance over a small sample can look like 30 or 70 percent by chance alone, so it should only be used to confirm the difficulty, not the version. The fourth check, the heal-ring check, is free once a warship exists and is the cleanest confirmation of the unit-level numbers, which are the part of the guide that should hold across every v0.35 minor version. Run them in that order, and if the first two pass and the third and fourth also pass, you are on v0.35 and the guide applies to your build, and if the first check already fails you are on an older build and the entire doctrine section of this guide is not describing your game, which is the reason the version check is the first thing the guide tells you to do rather than an assumption you are allowed to make.