With all running lines coiling can occur, but its particularly irritating if you are using a Mono Running Line.
Coiling can be caused by casting, a twirling fly or even when the line is loaded onto the reel. Here are Ed Wards insights on running line twisting:
If your fly line comes off the reel looking like a Slinky, then it may corkscrew enough in the water to twist up the runningline. One should be particularly mindful of coily flylines during periods of cold weather and especially if the flyline is Polyurethane based. The “fix” is to stretch the flyline out just prior to using it, to remove the Slinky effect.
Spey-type casts, being as “curvy” as they are, inherently produce some “natural” twisting action. Also, some conditions of casting seem to produce more line twist than others. Shorter types of flylines seem to twist more readily than do longer ones. Fly patterns tied “in the round” create more twist onto the line system than do flies tied with a “keel”. Large amounts of continuous, short casts of the same type, such as doing 30 right shoulder Snap T-‘s with only the head and 5’ of runner, can twist up a line system fairly quickly. The “while fishing fix” is to mix up one’s casts so that the direction of twist isn’t constant. In other words, instead of 30 right shoulder Snaps in a row, do 3 right shoulder Snaps, then change up to 3 left shoulder casts of some type.
Incorrectly spooling a runner can be a major source of line twist. The correct way is… reel and runner spool are aligned in-line with one another. In other words, as if viewing a car from above, if the reel is the right rear tire, then the runner spool needs to be the right front tire. Once the reel and runner spool alignment is correct, then the line needs to be feeding from off the BOTTOM of the runner spool and then into the bottom of the fly reel. If the line feeds from the top of the runner spool, to the bottom of the fly reel, then expect major line twist to occur!
We have found that the OPST Lazar Line has virtually no memory. We just spool it on (see Ed Ward’s notes above), give it a good stretch before fishing it for the first time, and voila! No more coils. You might have to repeat this procedure once or twice during the season but the more you use it the less it coils. Coming out of the close season we re-stretch it before using.
We have also found that when fishing rivers where you cant wade (e.g. Denmark’s Skjern Å) and have to cast from the bank, we find it better to use a stripping basket (god forbid!) like the Flexi-Stripper to hold the line – this avoids a lot of frustration with tangles in grass or rampant bushes.