I can do that I am a former RYA cruising instructor and have taught the shore based course. I have also provided out of hours support for students.
I charge per hour . But usually I would prefer to understand what you need To cover, an hour of active tuition is quite a lot in this regard
I can do Skype and email
I've done things like "remedial" chart work , tides etc which is where some students get bogged down
Perhaps its only a question of answering a few issues for you. You could easily put them up on CF for answer. Several RYA people here