Turning a Pen-and-Paper Battleship Game into an iPhone Duel
Paper Fleet Duel began with a game I remember playing using nothing more than an A4 sheet of paper and a biro. We drew a line through the middle of the page, placed dots on each side to represent ships, and took turns making a pen flick toward the opposing fleet.
A single dot was a small ship. Two nearby dots made a larger ship, and four dots formed the battleship. If the ink line crossed a dot, the ship was hit. Cross every dot belonging to a ship and it was sunk. The aim was to sink the opposing fleet before your own disappeared under a web of hand-drawn attack lines.
Recreating the flick
In the iPhone version, the player places a finger on their own half of the paper and flicks toward the opponent. The starting position affects the power of the attack: the farther the finger begins from the centre line, the more force the shot receives.
Once the push begins, the direction is locked from the first instant of movement. The player cannot steer the line after launch. It travels across the paper, and any ship dots it crosses are damaged. This preserves the risk, imperfection and satisfaction of the original biro flick.
Ships that behave like boats
The latest movement system gives each ship a defined front. A small chevron sits ahead of the leading dot to show the bow. Movement follows that heading, so ships travel forward rather than sliding sideways or instantly reversing.
Small craft can turn more sharply. Two-dot ships have a much smaller steering limit, and the four-dot battleship changes direction only gradually. A ship may stay anchored during a turn, while another begins moving during an attack. This makes the paper battlefield feel alive without losing the simplicity of dots and lines.
Levels, credits and building a fleet
The campaign is designed to teach the game gradually. Level 1 begins with two large ships and one small ship. Each level adds more vessels until Level 6 reaches the original full fleet size. Later levels can enlarge the playing surface, creating more room for movement and longer-range flicks.
- Start small: learn the flick with a three-ship fleet.
- Earn points: score by hitting and sinking enemy ships and winning matches.
- Choose upgrades: spend earned credits on additional ships for future levels.
- Keep progressing: completed levels, player names, credits and high scores remain stored locally.
An AI that is allowed to miss
The opponent uses lightweight offline game logic rather than a large language model. It evaluates the board and selects a plausible flick, but deliberate aiming error keeps it from feeling unnaturally perfect. Easier captains make wider mistakes, while higher difficulties become more focused without turning into guaranteed-hit machines.
Where the project is now
Paper Fleet Duel is currently an active SwiftUI iPhone prototype. Version 3.1 adds visible bows, forward-only movement, gradual steering for larger ships, saved names for the AI and second player, and softer AI accuracy. It also retains automated checks for the important turn handover between Player One, Player Two and the AI.
The next stage is continued play-testing: finding the right balance between flick skill, ship movement, fleet size, campaign rewards and AI difficulty. The goal is a game that feels immediately understandable to anyone who once drew ships on paper, while still having enough strategy to reward another match.
Policies, support and issue reporting
Paper Fleet Duel has dedicated privacy and support pages for App Store preparation and public testing. Bugs can be reported through the structured issue form, while private questions can be sent by email from the support page.