Fly rods are designed to cast a particular weight of fly line. The weight of a fly line is described by an AFTM number. This number is printed on the rod just above the handle. The AFTM number is based on the weight of the first 30 feet of the fly line. These numbers range from #0 (the lightest line) to #13 the heaviest line
Overlining means using a flyline that is heavier (has a greater AFTM# rating) than that recommended by the manufacturer. Do not use a flyline greater than one size above the manufacturer's recommended line rating. It may damage the rod.
Fly rods are designed to cast a particular weight of fly line. The rod loads or bends most effectively when used with this weight of line. With experience you will 'feel' a 'sweet spot' when you are casting with an appropriate length of fly line outside the rod tip.
The weight of a fly line is described by an AFTM number. The AFTM number is based on the weight (in grains ) of the first 30 feetof the fly line.
Consequently, if you know that you will be consistently making short casts with less than 30 feetof fly line outside the rod then it can help to overline the rod. The shorter length of a heavier fly line compensates for the loss of weight in the lighter fly line.
Now for the "geeky" bit.
The table below shows that there is not a precise relationship between weight and a particular AFTM number. For example, a line can be described as AFTM#5 if the the first 30 feet weighs between 134 and 146 grains (There are approximately 475 grains to the ounce).
Incidentally, this is probably the source for the constant debate between anglers on what brand of line works best on a particular model of fly rod.
When I am buying a fly line I check the lengths of the front taper and line belly. The relative lengths of these parts of the line can affect their casting characteristics especially when making short casts.
Here is the profile of a Snowbee XS Weight Forward Floating line.
|Line #||Wt (grains)||Range (grains)|
What diameter / breaking strain of tippet should I buy?
This depends on the size, weight and bulkiness of the fly tied on the end of your leader - the tippet section.
If you tie a big or heavy fly onto a thin tippet, it may break off during casting.
A thin tippet may not 'turn over' a bushy fly leading to poor presentation - the fly lands in the middle of a heap of tippet
It is difficult to pass a thick tippet through the eye of a small fly, and a thick tippet may interfere with the behaviour of a small fly.
This is about to get very "geeky" so I might as well give you the bottom line before your eyes begin to glaze over!
Now for another "geeky" bit - you really don't need to know this stuff unless you intend to subject yourself to cross-examination as part of a game angling instructors examination !
Tippet diameter is often described by using the X rating system. The X scale runs from 008X abbreviated to 8X (a very small diameter tippet) to 000X abbreviated to 0X a much thicker tippet. Matching tippet diameter to fly size is important for proper presentation of the fly.
How to calculate the size of tippet to use with a fly - the "Rule of 3"
(Unfortunately there is no standard way of representing hook size. Sizes vary between hook manufacturers. )
Sometimes the X value is not printed on a spool of tippet material. In that case the diameter of the material will be printed on the spool.
Here is a way to convert X to diameter in inches - the "Rule of 11":
Here is how to convert tippet diameter in inches into an X value:
How to calculate breaking strain of X rated tippet - the "Rule of 9":
Bear in mind that putting a knot into nylon monofilament reduces the breaking strain of the line. Therefore do not expect 3lb test line to break at exactly 3lb.
This table summarizes the relationship between:
Unfortunately there is no standard way of comparing "hook size" between manufacturers.
The author Datus Proper commented "A true size 14 weighing .18 grains and testing three pounds would make more difference at the trout's end than any amount of miracle fibers in fly rods."
If you use the clinch knot to tie your fly to the tippet (line at end of the tapered leader), five turns will hold with materials down to 4X.
But with smaller diameter tippets, five turns does not give a knot with sufficient bulk. Use the following X+2 rule with small diameter tippets.
|Tippet X rating||Clinch knot turns|