Persistent Route Plotting

Draw and edit a route on the map and return to it with a click of a button — a persistent route plotting tool for your U-boat.

✔ SAVE GAME COMPATIBLE — the mod keeps its route data outside your save, so disabling it never breaks a save.

Three tools are added to the map’s tool palette:

• Pencil — click to drop a waypoint, click on a leg to insert one midway, drag a waypoint to move it.
• Course protractor — click and drag to lay a leg by bearing and range, with a live preview and range ticks in your distance units (km or nautical miles).
• Course button — engages the plotted route. A small flag shows the state at a glance: grey (no route), red (off route), yellow (returning to course), green (on course).

On top of that:

• It persists — each route is saved per-save and reloads with it.
• Live navigation data — every leg shows its bearing; every waypoint shows the leg distance and, once you’re underway, the arrival time. Before you sail, the ETA reads "—". The final waypoint also shows the total route length.
• Progress at a glance — the stretch of route behind you fades as you sail, so the bright line is always the journey still ahead.
• Declutter for dense routes — Shift-click a waypoint with the pencil or course protractor tool to hide its labels (distance, ETA, course); Shift-click again to bring them back. Hold Shift while plotting to create waypoints with their labels already hidden.
• Name your waypoints — use the map’s marker tool on a waypoint to give it a name ("Patrol start", "Bingo").
• Fuel-aware — while you’re following a route, the fuel icon’s tooltip shows the distance remaining on your plotted route.
• End-of-route report — reach the last waypoint and the crew reports in. By default the boat comes to all-stop; an optional setting keeps your current speed so you sail on past the final waypoint, with the navigator calling out that you’ve reached your target.

German and Russian (AI translated) localisation is included.

Vanilla UBOAT lets you queue waypoints with shift + RMB, but those orders are throwaway — they’re erased as you pass them and don’t survive as a plan you can return to if you need to deviate off route to avoid an aircraft or chase a merchant. Persistent Route Plotting makes the route a deliberate, saved object you can plot, name, declutter, and follow whenever you like.

A source-only Harmony mod — no asset bundles, no prefab changes, nothing baked into your save. It adds its own map tools and reads vanilla navigation, so it should sit comfortably alongside other mods.

This mod has 3 configurable settings. You can edit them in the config.json file that comes with the mod. Found at C:Users<username>AppDataLocalLowDeep Water StudioUBOATModspersistent-course-plotterconfig.json

First, can change whether the map camera angle from top down (mod default) to vanilla tilt. Second, you can change whether the "return to course" button is disabled when you are lost (default is true). Third, you can change between 2 behaviours when you reach the last leg of your course, the default (false) is that your boat will come to a full stop, the other option is that your crew will call out that they’ve reached the destination and then continue ahead at the same course and speed as your last leg. Change between Kn and KM using vanilla settings.

If you snap the endpoint of a vanilla map annotation (a line or marker) directly onto a plotted waypoint, that annotation disappears the next time the route redraws. Plot your route’s waypoints first, and place vanilla annotations clear of them.

When you have an "out and back" type route the navigation function can get confused and go to the nearest waypoint – your endpoint, instead of the proper one. I’m working on a fix but for now just draw one way routes out and a one way route back later to avoid the problem.

I make a range of UBOAT mods — from historical-realism tweaks to modding & debugging tools. Check them out if you liked this one:
Expanded Deck Gun Ammo
Historical Type IX fuel capacity correction
The Drydock – Modding and Debugging tool
Persistent Route Plotting – new tools for navigation and plotting

Disclaimer: Has a lot of AI code, it may contain errors but I spent about a week testing this so it should run smoothly.
Copyright: Attribution-NonCommercial CC BY-NC — in other words, remix/redo it, share it, but acknowledge the original authors and don’t commercialize it!