I should have clarified my post a little bit since I realized I have no idea what size of a tear you're describing. I've only ever attempted repair on small holes and tears (ember burns, puncture holes, etc.) If you're talking about a large tear (anything over a couple inches) then patch repair is less likely to be effective.
Also, it probably goes without saying but keep in mind what you're dealing with and make sure you gingerly test your patch work to make sure it's holding well. AKA Hang your hammock low and gradually put it through some more stress to make sure it holds. A patched hammock can truly function 'good as new' for a long time to come but always keep in mind that the structural integrity has been altered so you should always hang in a safe way to minimize the chance for injury in case the patch fails at some point. Obviously checking on the patch from time to time and replacing it if necessary is good practice as well.
That's all my fatherly hammock repair advice for now.