How to play. Sixty nautical miles to the hex, six hours to the watch.
Choose a scenario from the opening card. The Denmark Strait is the short one — twenty watches, both fleets already close — and is the best place to start. Rheinübung is the full operation. Sortie of the Twins is a commerce raid rather than a duel.
Then choose your side and the quality of the opposing staff. Playing the Royal Navy is a searching game; playing the Kriegsmarine is an evasion game. The chart room opens on your main body.
| Action | How |
|---|---|
| Take a force in hand | Click her counter |
| Step through a stack | Click the same hex again |
| Lay off a course | Click open water |
| Pan the board | Drag, or the arrow keys |
| Zoom | Wheel, or + and − |
| Next force | N |
| Put down the force in hand | Esc |
| Work the watch | Space, or the button in the bar |
Hovering any hex reads out its grid reference, its position, the weather in it, and its range in hexes and miles from whatever you are holding. The index map in the rail shows the whole ocean; click it to bring that water to the table.
A watch is six hours and both sides move at once. There is no "your turn". You give orders to as many of your forces as you like, then press Work the watch, and everything happens together in this order:
Because both sides move at once, an order is a guess about where the enemy will be at the end of the watch, not where she is now.
Click a force, then click the sea. Her track is drawn along the water she will actually steam over — round Iceland, not through it. With a force in hand, the hexes she can reach this watch are outlined in brass; change her speed and the outline changes with it, because it is drawn from the same figures the watch will use.
Speed costs oil, and the cost rises steeply. A ship at full speed empties her bunkers in a fraction of the time she would at cruising speed, and a ship far from a tanker or a friendly port with empty bunkers is out of the operation. A cruiser can be told to hold a patrol line: she stays on her billet and sweeps the hexes around it, and she searches far better there than a ship merely passing through.
You do not order an attack. If two forces end a watch in the same square of ocean and at least one of them wants an action, there is one. Whether the other can decline depends on her legs, the visibility and the dark — and on whether anyone is holding her on a firm plot.
Actions run in three-minute rounds. A director that holds the same mark at a steady range gets on and hits far more often; when the range walks, it loses the ladder and has to start again. Belt and deck armour are separate: at long range shells fall steeply and find the deck, which is why a thin-decked battlecruiser is in real danger at twenty thousand yards and safer close in.
Both sides score. Sinking warships, sinking merchant tonnage, getting raiders home or stopping them — each is worth points, and your total is read against par: what a first-class staff makes of the same position. Beating par is the test, not beating the number your opponent happened to get.
There is no single win. The closing card gives your score, par for your side, and the margin between them, with the band that margin falls in — from a signal victory down. As the Royal Navy you are scoring by sinking the raiders, especially the flagship, and by getting your convoys through. As the Kriegsmarine you are scoring by sinking merchant tonnage and by bringing your raiders into a Biscay port.
The operation ends when every raider has been sunk, when every raider that went to sea is back in harbour, or when the watches run out. A German player is not hurried out: the raiders start alongside in Bergen and the operation waits for you to decide when to sail.
You can also break off at any point with the button in the bar. The game is scored as it stands — breaking off is not a way to avoid a bad verdict.
The game saves itself after every watch. One saved game is kept, and the opening card offers to resume it, naming the scenario, the watch and the side. Starting a new operation or reaching the end of one clears the save.
Your preferences — the hex grid, the reach outline, weather shading and convoy routes — are kept separately and survive between games.
Saving needs browser storage. Opened straight from a file rather than through the portal, the browser refuses the page any storage at all; the game says so on its opening card and plays normally otherwise.