MORE than half of Scotland's lifeline ferry network is operating outwith its working life expectancy leading to new calls for a shake-up of the crisis-hit services. The Herald can reveal that a new analysis shows 16 of the state-owned ferry operator's 31 working ferries deployed across Scotland is now over 25 years old. It comes as the network was hit with further disruption through new ferry breakdowns over the last month - and a fifth delay to the completion of repairs to CalMac's biggest ferry MV Loch Seaforth. It now not expected back in service till this May 28 at the earliest, having been pulled in for engine work a month ago.