[smurphny]

It's not very common for this to happen on a halyard but it is often a problem on furlers. I find that it is most important to maintain tension on the wraps so that a top wrap cannot slip into a loose coil and then get cinched in as more tension is applied. If a large amount of tension is applied for a short hard yank, such as is often necessary on a furler, it can sink the top coil underneath because the rest of the spool was coiled at that lower tension. So I guess the solution is to TRY to apply constant, equal tension.