Over 70,000 Scottish ferries have been delayed or cancelled on routes operated by CalMac since October 2007, according to figures obtained by a freedom of information request.
Figures indicate sailings on 29 routes over the period were delayed 34,124 times and cancelled 39,314 times.
It means in just over a decade, the equivalent to around 117 sailings a week have been delayed or cancelled.
The worst affected routes include those running between Ardrossan to Brodick and Wemyss Bay to Rothesay.
In 2015/16 a total of 6,135 sailings were abandoned, the highest number recorded in the last decade.
A total of 1,884 ferries were cancelled in 2009/2010.
Scottish Conservative Transport Spokesman Jamie Greene said: “SNP management of the ferries has been nothing short of disastrous.
“This astonishing level of delay and cancellation must be extremely inconvenient to local residents and tourists and highlights the poor service that many islanders are receiving as a result of sustained underinvestment in our port and ferry infrastructure under the SNP.
“CalMac has admitted there is very little resilience within the fleet nor does there appear to be any long term planning.
“As things stand the situation is nearing crisis point during the summer season and ultimately island communities will be let down when things go wrong.
“The SNP clearly has absolutely no handle on this situation and must explain themselves to the Scottish Parliament and the Scottish people.”