How does Startop get involved in the plan to save Magwitch? Do you think it is a good idea?

Startop will take Magwitch and Pip down river . He is a good river man and doesn't ask questions,

"I have thought it over, again and again," said Herbert, "and I think I know a better course than taking a Thames waterman. Take Startop. A good fellow, a skilled hand, fond of us, and enthusiastic and honourable."

I had thought of him, more than once.

"It is necessary to tell him very little. Let him suppose it a mere freak, but a secret one, until the morning comes: then let him know that there is urgent reason for your getting Provis aboard and away. You go with him?"