Cutting a spey line for use with a sink tip is relatively simple in theory; however, what most people tend to do is cut the Spey line back to the length of the sink tip which can pose some technical problems. While this technique works in most cases, and it would not make a difference for most beginners, it could have an impact on your cast. For example, if your sink tip is 15 feet and you cut an equal amount from the spey line, that 15 feet could weigh 100 grains or it could weigh 200 grains, depending on the line you use. The new Skagit style spey lines, also known as short belly lines, have a thick, short and heavy belly. If you cut 15 feet off this line it will have more grain weight per 15 feet than a traditional longer belly line. So, cutting 15 feet off the front section of your spey line may be much more than you need to cut.
Before you cut your spey line, it is important to know how much to cut and this depends on how much grain weight your sink tip is. If you cut 200 grains off of your spey line, and your sink tip is only 100 grains, your line will not cast properly for your rod. Every sink tip has a different grain weight and, while there may be others, I do know that Rio is one company that displays its grain weight on the package. The Rio sink tips are 15 feet in length and range in grain weight by rod weight. A Rio 9 weight, type 6 sink tip is 15 feet and weighs 129 grains. The sink tips in the same line weight all have the same grain weight. For example, the type 3, type 6 and type 8 in a 9 weight all have the same grain weight of 129 grains. So in that situation you would cut 129 grains off the front of your spey line. Another option is from Umpqua Feather Merchants. Umpqua manufactures a line scale, which most shops sell, and they sell for around $25.00 CAN. This tool is must for today's spey anglers. They are great for measuring the grain weight of a whole fly line or a small section of a fly line. You simply coil up some of the line and hook it on the scale and it will tell you how much it weighs. Too easy!
Tight Lines, Rick Baerg