From the Island Sounder, today:

Washington ferries awarded $4.8 million to extend lifespan of six aging vessels by up to a decade. Washington State Ferries (WSF) has received $4.8 million in federal funding to refurbish passenger areas on six aging boats in its ferry fleet. The grant will pay for upgrades on all six of WSF’s Issaquah Class Vessels, originally constructed between 1979 and 1982 and currently serve travellers in Fauntleroy, Vashon, Southworth, Mukilteo, Clinton, Anacortes and the San Juan Islands.

https://www.islandssounder.com/life/ferries-awarded-4-8-million-to-extend-lifespan-vessels/

The Washington State Ferries, Issaquah class are 328 feet long and 2 477 tons and serve 90 mile crossings from Seattle to nearby isles..

CalMac has only one ferry in service, built before 1983 – the MV Isle of Cumbrae, half the size, 100 feet and 169 tons, serving the short 4 miles, Tarbet to Portavadie crossing.

The six WSF ferries will be well over 50 years old by the end of the new projected lives.