Sloane were operating the Starspeed 92 and a 109 last year while they were waiting for their 139 - St Marys objected to the S92 noise so it only did the Tresco run, I came back in the 109 last year and there were only 4 of us pax on board so economically that must have been at best break-even.
I think they had a 139 coming from China which then fell through so sourcing another may be a reason for delay in providing a full service with it.