diff --git a/src/game-logic.js b/src/game-logic.js
new file mode 100644
index 0000000..58accda
--- /dev/null
+++ b/src/game-logic.js
@@ -0,0 +1,51 @@
+export const PLAYER_MAX_HULL = 100;
+export const DEFAULT_PIRATE_SHOT_DAMAGE = 6;
+export const PLAYER_HIT_COOLDOWN_MS = 300;
+
+export const normalizePlayerDamage = (
+  rawDamage,
+  fallback = DEFAULT_PIRATE_SHOT_DAMAGE,
+) => {
+  const parsed = Number(rawDamage);
+  const value = Number.isFinite(parsed) ? parsed : fallback;
+  return Math.max(1, Math.min(25, value));
+};
+
+export const reducePlayerHitQueue = ({
+  hull,
+  lastHitAt,
+  now,
+  damages,
+  cooldownMs = PLAYER_HIT_COOLDOWN_MS,
+  maxHull = PLAYER_MAX_HULL,
+}) => {
+  let nextHull = Number.isFinite(hull) ? hull : maxHull;
+  let nextLastHitAt = Number.isFinite(lastHitAt) ? lastHitAt : -Infinity;
+  let appliedHits = 0;
+  let ignoredHits = 0;
+  let totalDamage = 0;
+
+  for (const rawDamage of damages) {
+    if (now - nextLastHitAt < cooldownMs) {
+      ignoredHits += 1;
+      continue;
+    }
+
+    const damage = normalizePlayerDamage(rawDamage);
+    nextLastHitAt = now;
+    nextHull = Math.max(0, nextHull - damage);
+    totalDamage += damage;
+    appliedHits += 1;
+
+    if (nextHull <= 0) break;
+  }
+
+  return {
+    hull: nextHull,
+    lastHitAt: nextLastHitAt,
+    appliedHits,
+    ignoredHits,
+    totalDamage,
+    gameOver: nextHull <= 0,
+  };
+};