The knot will weaken the line upto 50% at the point where the knot is. To loosen it off, the best way I found is to soak the knot in warm water then simply knore at the knot gently - this can take upto 30 mins but cheaper than replacing all your lines.

*This is why it is important to throughly check your lines when setting up!*

Thanks heaps for that info guys, I used a bit of both advice. Soaked the knot in warm water first for a couple of minutes then loosened it by lightly hitting it with a piece of nylon block, lightly chewed on the knot as well & it came out a treat!! There's no way i would have thought it would have come out considering how bloody tight it was, like a rock.

Thanks again and good winds to you

Cheers

Mark.