In the rod/line match up (here) we briefly discussed the difference between a weight forward line and an old school double taper line. But the different types of line don’t stop there, and in a world of bellies, sink rates, “intermediate”, type 6, and more, we’re here to clear up some of the confusion.
We’ll start with the floating line selections. As previously mentioned, a weight forward line is the most popular option for generating line speed and “loading” your rod more quickly. This style of taper puts the weight of the line towards the front (usually the first 20-30 feet of a 100 foot line) and allows an angler to shoot line further as well. If the belly section of the line is shorter and more dramatic, it’s best suited for louder styles of presentation (think streamers, poppers, etc), or for indicator fishing where you’re trying to turn the line over with multiple items on your leader/more weight. If the belly is a bit longer and spread out, the fly will land more gently (like you’ll need for dry fly presentation).
These weight forward principles carry over into Spey fishing as well; shorter floating heads (typically called Skagit style) are great for learning on/loading your rod quickly, and will turn over heavy flies more easily than longer bellied lines (Scandi style lines) that are more suitable to dry fly and skating presentations. There are many in-betweens that don’t fall under the heading of Skagit or Scandi, and your local fly shop is the place to go to find the best suited head for your two-handed rod and skill level. If your local shop isn’t suited for two-handed fishing (luckily a rare occurrence nowadays), then the Pacific Northwest is a great place to look for fly shops you can call and order from; spey fishing is immensely popular there and the shops are more accustomed to supplying these particular types of line.
The next class of line after floating are the intermediate lines. These also come in different configurations of belly and taper, but the key difference is the sink rate. Intermediate lines sink the slowest of any line on the market designed for sinking; typically 1-2 inches per second (ips). These lines are popular for multiple settings; in lakes with weighted flies or while trolling flies, in saltwater where a heavier weighted line would hang up in barnacles and other obstacles, and even in Spey fishing deeper or higher flow rivers. A good intermediate line is extremely handy to have in multiple weights for different rods; often (but not always), fish are deeper than a floating line has access to, but are still looking up for their food. Once they’re looking down (like when Rainbows are on the lookout for salmon eggs during spawning season), it’s a different story, but for Tarpon in Costa Rica and even swinging steelhead in heavy flows on the Olympic Peninsula in Washington, intermediate sink rate lines are useful again and again.
Full sinking lines are categorized in a couple different ways. It’s also worth noting that some lines may only have sinking tips, with the remaining line floating. These are ideal for streamer fishing and allow you to cast more efficiently. With full sink lines, most are used for lake fishing when you’re trying to get to the maximum depth possible. Nowadays lines are typically labeled in the ips system, with the heaviest lines maxing out around the 7-8ips range.
Other terminology you’ll hear for sinking lines are “types”, and “level T”. For example, type 3 line sinks at a rate of 3 ips, and type 6 line sinks at a rate of about 6 ips. T-8, T-11, and T-14 are all examples of tungsten core lines, with a grain weight of 8, 11, and 14 grains per foot, respectively. The more grains per foot, the heavier the line, with varying sink rates depending on overall length (but obviously, more grain weight means heavier, which means a faster sink).
If you’ve started exploring the world of spey/double handed fly fishing, then you’ve become somewhat familiar with the different line system it uses; grain weights rather than the typical “WF5F” on the side of the box. While every line (both for single hand use and for two handed rods) has a grain weight, single hand lines tend to use the simple numerical ordering system to pair the lines with their corresponding appropriate rod. But in spey fishing, there’s quite a bit more flexibility and range of lines you can use. Typically, if you’re using a shorter shooting head, you can use one that’s a heavier grain weight than if you’re using a longer head. This relates to sink tips in an important way; if you’re already using a shooting head that’s overloading or on the upper end of what your rod is able to cast, then tacking on another 10-15 feet of sink tip is going to make it very difficult to cast successfully. This is something to keep in mind when purchasing your shooting head; if you know you routinely fish deep or swift (or both) water and regularly throw heavier sink tips as a result, you’ll want to select a shooting head whose grain weight is in the middle or lower end of the range meant for your rod. It is not uncommon to have more than one shooting head for one rod; simply connect whichever head you're using to your running line via a loop-to-loop connection, just like when attaching a regular tapered leader to the front of your single hand fly line.
No matter what conditions you find on the water, from fishing light flies that need to get down in a lake, casting baitfish patterns to sea-run fish, or swinging flies to hungry trout, there's a line out there suited for your needs. Hopefully this guide helps you sort out some differences so you're equipped with the knowledge you need next time you stop by your local fly shop.