Yes they are single pliot AND they have no autopilots (or weather radar or HSI's or RMI's or GPS, only a vac DI and some VOR's) but they have an allowance due to the type of shorthaul flights. In fact even the Jetstreams used by blueislands don't have autopilots. Another fun issue with all this work load is a passenger sitting in the right hand seat with working controls in front of them
A buddy of mine has been flying the Channel Islands for some years and I think has only canceled one flight due weather (and that was crosswind limits). They scud run and come accross the water I think down to 500'. Thing is when loaded in a Tri you are coming down with an engine failure so all you have achieved is a 200% increase in the chances of having one. If I remember you need 1500 hrs to even be considered for them.