BIDDERS for the new Gourock-Dunoon ferry service will have to provide larger vessels on the route to reduce the number of services cancelled by poor weather.

Transport Scotland said operators will be expected to retain the current half-hourly frequency and to deploy vessels measuring least 40 metres (131ft) on the new 12-year contract, which is due to begin in June 2017.

Transport Minister Humza Yousef said this would "help address the current issue of reliability on the service, and offer greater resilience during periods of adverse weather".

The route is currently served by the MV Argyll Flyer, measuring 26 metres (85ft), and a motor catamaran, MV Ali Cat, measuring 19 metres (62ft).

There were 705 weather-related cancellations in the six months to the end of April 2016 - equivalent to around 27 per week - from a total of 9,528 scheduled sailings.

The service is currently operated by Argyll Ferries, a subsidiary of Scottish Government-owned, David MacBrayne Ltd - the parent company behind CalMac.

Bidders will also be "encouraged" to operate a commercial vehicle-carrying service, alongside the publicly-funded passenger ferry service.

It comes after controversy in 2011 when Transport Scotland scrapped the car ferry in favour of a passenger-only service for the route.

A private vehicle-passenger ferry service is operated between Gourock and Dunoon by Western Ferries, departing from McInroy's Point, around 2km (1.2 miles) from Gourock town centre.

Mr Yousaf said: “We want this new contract to provide greater support to the communities that rely on this important transport link. By bringing more resilient vessels to the route and continuing to invest in harbour infrastructure, we hope to make tangible improvements to the service and continue to support the economies in Argyll and Bute and Inverclyde.”

Interested parties will be invited to submit formal tenders later this summer.