Yes, fairleads are a must
My boat came with the origanl Jib and had no fair leads. the first time I used it, I just wrapped the Jib sheat around the winch. Just like you describe, it didn't work well and kept coming off of the winch. So, I took a couple of blocks and tied them to the deck mounted loops which are meant for this perpouse. It work very well but the blocks flopped around and beat up the deck. Next I took a small section of hose and place it between the block and the deck. Some systems use a spring where I used the hose. This keeps the block up high and in line with the winch and it doesn't flop around. I went this way because it was free and this kind of gear is very expensive.
