I really enjoy watching a fluorocarbon level line slowly unfurl from the rod tip in its graceful loop, stretching out and lightly dropping the fly first. I also enjoy how how little sag is in the line when keeping the line off of the surface of the water. There are some situations where I look at a furled line as a useful tool. I also understand that some people like furled lines because of the way that they cast. As with everything in tenkara, it all comes down to personal preference.
One thing that I have discovered over the past few years is that not all furled lines are created equal. Here are a few of the furled lines that I have tried, and a few thoughts about them. Again, bear in mind that some quality I may like about a line may be the very thing you dislike. I think you have to cast different lines until you find one that suits your temperament and casting style. It's really not something you can "group-think." Another thing to remember is that comparing them to level lines is like comparing apples and oranges. Furled lines are going to sag more, and it takes a little more doing to keep them off the water. Some are just too heavy to not keep 6-12" anchored on the surface. They definitely load the rod a little more (whereas casting a level line typically depends on the rod to do the work), which is something some people prefer, especially if coming from a background of 'western' fly-fishing. Loading the rod can also be beneficial especially if it has a stiff profile, like some keiryu rods.
Tenkara USA "Traditional Line"
I bought the first generation of this line with my first tenkara rod, which was an 11' Iwana. I think it was made of furled nylon, but I can't remember. I do remember thinking it was the bees knees until I bought a light level line, and then not so much I gave this one away to a friend, and bought the second iteration that was made of furled kevlar. I still have this line, though I don't really fish it anymore. In fact I haven't fished it in so long, I don't think I could give a very fair assessment of it. I remember it casting graceful loops and turning over a dry-fly very well. I also remember it being on the heavier side, especially when wet. I know a lot of people fish and love this line. I keep it in my chest pack at all times, however, as an emergency backup line (in case I forgot a line or something blows up).
As I mentioned in an earlier post, I finally got around to twisting a couple of horsehair lines, mainly as a winter project. I took it fishing and fell in love with the way it casted, especially on my 9 foot Iwana, which is crisp but not overly stiff. I mainly fish this combo when I know that the monster trout of the stream is going to be about 6" or so. I recently added a floro sighter to the end, as the white of the hair is easy to lose in some lighting conditions. I also started conditioning my 9 foot line with Mane and Tail conditioner, but if that makes a difference or not remains to be seen. My 9 foot line is made up of four sections, going from five to three strands of hair. There is some slight sag, but it is light enough to keep off the water with ease, and delicate fly first presentations are a snap. Horsehair lines are not very durable, at least not compared to modern materials. I have broken a section on my 12 foot line, but fortunately repairs are easy.
Zen Outfitters Level Furled Line
A fly shop in a nearby town recently went out of business, and while that is unfortunate, I did pick up a some great tying materials at a fraction of the price. This line was also half off, so I figured I wasn't really losing much by giving it a try. The line I purchased is about 13 feet in length, and appears to be made of furled monofilament. It is a bright green color, and is pretty easy to see in most conditions. The packaging states that the line is treated with some kind of floating treatment. The line actually does float, though after a bit of fishing the tip of mine will sink a little. The line is heavier than any of my other furled or twisted lines, and will load a pretty stiff rod. I have casted it on both my Tanuki 375 and Oni 450, which are on the stiffer side, and this line will load fairly deep into the rod. With that weight comes a great deal of sag, and I have found it best to keep about 6-12 inches of the line anchored in the water. I don't fish this line very much, because it doesn't really mesh well with the way I like to use tenkara. But the line does have a few benefits that could be useful from time to time. Because of its weight, the line will punch through some pretty decent wind. On those windy days, especially on an open tailwater, anchoring that first bit of line on the water is nice. No one likes having the wind blow their line up and out of the water, fly and all, dangling like yesterday's laundry. And because it actually floats, I could see dry fly enthusiasts liking this line. The shop also had an eight foot version, and I've kinda kicked myself for not getting it. I think it would have loaded my Shimotsuke Kiyotaki 24 enough to feel like it was actually casting! That reminds me of another benefit to furled/twisted lines: on really small streams, in spots where casting loops becomes problematic, the slighter heft can provide nice turnover for aerial roll casts or bow-and-arrow casts, especially in the wind that tends to blow through these tunnels.
After being delighted with the horsehair line, I was wondering if it would be possible to replicate the feel with modern materials. While I have yet to twist any monofilament or fluorocarbon, I decided to purchase a twisted line as a frame of reference. I almost purchased a Nissin line, but when Tenkara-ya offered another round of the furled Sebata-san lines, I couldn't resist. I purchased the 3.8m, but I wish I had also gotten the 4.5m as well. I have only had the opportunity to fish this line once, but I hope to spend more time with it as the spring begins to warm. My initial impression was surprise, for the line was much lighter than I had anticipated. When I refer to weight, I am referring to weight in hand, at the rod tip. I did not weigh the lines themselves. I think this line will be a pleasure to fish.
So there you have it. Not much of a review as much as personal musings about a couple of furled lines that I've tried. With light-line tenkara, there is so much control over the fly that these lines rarely make it into the mix. But like I said, there is a time and place for everything, and I think its good to experiment, fail, and be a dynamic angler.