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