* @param colony The <code>Colony</code> to damage ships in.
     * @param cs A <code>ChangeSet</code> to update.
     */
    private void csDamageColonyShips(Unit attacker, Colony colony,
                                     ChangeSet cs) {
        List<Unit> units = colony.getTile().getUnitList();
        while (!units.isEmpty()) {
            Unit unit = units.remove(0);
            if (unit.isNaval()) csDamageShipAttack(attacker, unit, cs);
        }
    }