[Gillie]

I'm trying to figure out the starting point for some lines. I'm probably oversimplifying this, but if a rod loads well with a grandspey 9/10 which according to the website is a 900 grain line, if I wanted to put a WC on that same rod would I be looking for a 900 grain short belly line. For the windcutter that would be an 11/12/13 to be closest to 900 grains.

For arguments sake I'm assuming that the full head is being cast for both lines.

Does this fail to take into account taper or is it this simple to get to a starting point for trying different lines ?

Gillie

 

[Gillie]

Peter,
This is one of the things that confuses me when it comes to selecting lines. Shouldn't a 9/10 line be the same number of grains whether it's a short belly or long belly ? I'm sure it makes sense but I don't understand how two lines with different grains can load the same rod effectively.

Gillie

 

[Moose]

Well...

Think of it as "X" amount of weight spread out over a very short span will feel heavier than the same weight spread out over a very long span, at least in terms of trying to move the weight.

If you took 900 grains and put it into a 50 foot line it would feel very heavy and hard to lift and move with your 8 weight rod, but if that same weight were spread out over 90 feet it would put a lot less of an initial amount of resistance against that rod when trying to pick it up and move it. But once you got the whole thing up and moving, creating a load against the rod....

Was trying to come up with a clever analogy, maybe someone else will be able to better put it into perspective.

 

[Gillie]

Moose,
That makes sense. The more I think about it and read Peters writings it's starting to make sense. I think it's going to be the same thing where I need to try a few different lines. The principle of the weight being in the D-loop and spread out over the line is clicking.

Gillie

 

[SSPey]

I prefer more grains in long belly lines than short lines.

 

[Lohi]

Gillie, Peters Casting Weight Model really explains the subject. However, as you say that GS 9/10 works with you, be aware of the legth of line you are using with it.

An alternative way to figure out a new line is the new Spey Standard. Obviously you cannot use directly it as long as the lines in the shops are labeled with the old line designations. However, on my tiny homepage (Suomalainen Speysivu ), you will find a SpeyLine Calculator, that you can use to calculate the SpeyStadard of any line, given that you have the belly length and weight available. Just first put in the length and weight of the belly (or the portion of it you are actually using), and you get a reference number. Then dial in the length and weight of the belly of the line you are considering, and you get another number. The closer these numbers are, the closer the lines are theoretically, as far as the Standard is concerned. Please note, that this is a rough guide, and does not take into account the mass profile of the line, as Peters model does. Obviously actually casting the line with the rod is the best way, but not always possible (not to us in Finland at least).

PS. The assumption that you cast the whole GS is very crucial, as if you actually cast only 70 ft of the 95 ft belly of the GS, you will get too heavy shorter belly lines with both the abovementioned approaches.

WBR, Sauli Liukkonen, Finland

 

[Gillie]

Lohi,
Much of this is theoretical. I can not consistently cast a full GS but I certainly wish I could. This question arose because I'm looking for a rod for a very specific situation (but one that I fish very often). Some of the rods I'm looking at are most often discussed by the long liners and lining reccomendations are usually in terms of GS or other long bellies. I'm trying to figure in my head how to convert some of this information to lining similair rods with mid-belly or short-belly lines.

Luckily it looks like I'm going to have the oppurtunity to swing a few of the rods at upcoming claves and hopefully I'll manage to get the lines I'm interested on them.

Gillie

Lohi,
Just tried your spey line calculator. Us poor Apple users are left out in the cold . So I see Bill Gates has gotten to you to . But the table with the spey line standards is helpful. I have a PC in my office at work I guess I'll have to pry myself away from my work today and look at it there

Gillie :hihi:

 

[JDJones]

Apples & Oranges

Lohi,
Much of this is theoretical. I can not consistently cast a full GS but I certainly wish I could. This question arose because I'm looking for a rod for a very specific situation (but one that I fish very often). Some of the rods I'm looking at are most often discussed by the long liners and lining reccomendations are usually in terms of GS or other long bellies. I'm trying to figure in my head how to convert some of this information to lining similair rods with mid-belly or short-belly lines.

Luckily it looks like I'm going to have the oppurtunity to swing a few of the rods at upcoming claves and hopefully I'll manage to get the lines I'm interested on them.

Gillie

Lohi,
Just tried your spey line calculator. Us poor Apple users are left out in the cold . So I see Bill Gates has gotten to you to . But the table with the spey line standards is helpful. I have a PC in my office at work I guess I'll have to pry myself away from my work today and look at it there

Gillie :hihi:

Sorry Gillie, I just couldn't resist that one. :chuckle:
But, in reality, It really is apples & oranges tryring to compare long & short belly lines. They dictate the use of different casting styles. And as such, they load the rods differently.
I am not sure I can explain the whys. But a GS or XLT line has a long front taper with most of the weight concentrated further back in the belly. These lines require a "touch & go" type of cast with very little line stick.
A Skagit line on the other hand, has so little line mass in the abbreaviated D-loop, that it requires a good bit of line stick to load the rod.

 

[sean]

As others have mentioned long bellies are different animals than lines 65' and under. It is just a matter of how the grain weight is dispersed throughout longer lines to get them to work correctly. The grandspeys are now rated for the correct rods and the xlts are under work to get this done as well so things should get easier.

Since you are talking rio lines I still find Simons reccomendation chart the best place to start when thinking about lines to use on a given rod.

http://rioproducts.com/pages/speyrecs.asp

Taking the A and B desination for a given line and rod which will give you a grain range of sorts. This is pretty good at using for other manafacturers lines in the same length as the RIO lines. IE compare the midspey weights to the airflo delta long , windcutter to the sa short head, etc. This has worked for me 95% of the time when looking for new lines for a rod I have.

-sean

 

[Gillie]

I talked to a friend at work today who does research and has a good knowledge of physics, but no interest or knowledge in fly fishing. After I explained the problem / question to him, his initial theory was that any lever or spring would require a different amount of loading to throw objects different differences. That makes sense to me from the perspective that you can tip cast shorter distances while the butt often has to be loaded to cast a long line.

Would others agree that you need less load on the rod to cast 50' of line as opposed to 100' of line ? If that is the case then it would make sense that a shorter head would need fewer grains.

Gillie

 

[Gillie]

Sean,
I've left the world of reality at this point and am simply pontificating over how rods and lines work. . I really need to get out on the water.

Gillie

 

[JDJones]

I talked to a friend at work today who does research and has a good knowledge of physics, but no interest or knowledge in fly fishing. After I explained the problem / question to him, his initial theory was that any lever or spring would require a different amount of loading to throw objects different differences. That makes sense to me from the perspective that you can tip cast shorter distances while the butt often has to be loaded to cast a long line.

Would others agree that you need less load on the rod to cast 50' of line as opposed to 100' of line ? If that is the case then it would make sense that a shorter head would need fewer grains.

Gillie

Your friend, the physics major, has it right. To cast (cast, not shoot) a longer line, you need to load the rod deeper into the butt section in order to tap into that reserve power. It takes more grains to get that deep load.

 

[Gillie]

Peter,
He did explain that velocity plays a role in the load a mass will place on a rod (or any lever) but assuming the same velocity his principle will hold true. There are light long belly lines that throw far but on lighter rods. I would assume on those rods the long belly will continue to load more deeply than an equivelant short belly with the same stroke.

Plus, his principles do not take into account taper and line tension with the water. he knows nothing of fly-fishing. It is a very simple explanation why the two don't need to weigh the same on the same rod.

Gillie