Twice in the past two weeks I have received after hours calls on the emergency line with the same problem, an overwrap in the jib furling drum preventing the jib from being rolled up. In both cases, the boat was docked safely and the overwrap taken care of, however, prevention would have eliminated quite a bit of anxiety on the part of the skippers.
Most cases of jib furler overwrap are caused by either by allowing the furler to “free spool” while the jib is deployed or by leaving slack in the line after the jib is out. To prevent an overwrap, put a little restraining tension on the furling line as the jib is deployed. Don’t let the jib come out too fast. Once deployed, remove all slack from the furling line before cleating it securely.