CastFlys.Net

Fly Casting Education and more...
Home Page
Hosted Trips
Instructors Workshops
Casting Instructors Certification
Summer Casting Classes
Private Casting Instruction
Tackle & Techniques
Fly Lines
Line Basics
Taper Design
Before Buying
Shop for Lines
Casting Videos
Long Beach Casting Club
Fly Casting Links
Books/DVD's
About Us
Contact Us
Fly Lines  
Click here to visit our new website, Castflys.Com
 
First lets take a look at how lines work during a cast. This will help to understand why lines are deisigned as they are.
 
As the rod moves during a casting stroke it pulls the line in a somewhat straight line path. When the loop is formed the leading edge momentum pulls on the upper and lower legs of the loop. As the line unrolls the energy is dissipated by air resistance to the leading edge of the loop. This energy is passed off into the air in the form of a small amount of heat energy. When the line rounds the corner of the leading edge it becomes more or less static as long as the line isn't shot to extend distance. 
 
E=V2*1/2M – Energy is equal to Velocity of the line squared, times half the Mass of the line.
 
The smaller the diameter (mass) in the line, the greater effect air resistance has upon its leading edge. This creates less capacity for carrying the energy and therefore energy gets dissipated.
 
The greater the loop surface the line presents to the air flow the greater the dissipation of energy. When less line surface is presented, less dissipation takes place. This allows the line to travel farther for a given amount of energy.  
 

 

 

This illustration shows an open loop... Because of the amount of surface the leading edge (loop) presents to the air as it travels forward, the line will slow quickly and may not turn over and lay the fly out straight. This is an inefficient loop when attempting to maintain distance or accuracy.  

 

 

 

 

This illustration shows a tight loop. Notice that the leading edge presents much less surface to the air. This efficient loop shape will be more accurate and will travel farther than the jone above, especially into a wind. 

 

 

This illustration shows the affects of poor line or leader design. If the energy is not efficiently dissipated there will be too much energy remaining in the line as it turns over. The line will continue to travel in the same direction that it was sent as it turned over, so it continues in a downward direction. The line then drags the leader along with it. On a long cast, the last few feet of the line and the entire leader will end up in a heap as much as 10-15 feet short of it's intended target.  

 

 

 

Now lets take a look at the Basics of Fly Line Design.