I think the SNP would be quite happy at the moment if this issue had the worst optics of any issue they are facing.
Hmm... The wider ferry issue is deeply significant in the communities affected and it gives the impression of the SNP as caring only for the central belt. Add to that both Labour and Tories can point to a greater success in building ferries when they were responsible, and that the issue involves a lack of transparency, and fiscal imcompetence and it's easy to portray it as symptomatic of wider issues.