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Articles

The Spine !

What makes one rod cast better than another can be a complex subject. The idea of this web page is to give you a better understanding of why some rods cast and play so sweetly and others kick like a mule. I will endeavour to keep it simple, so give this page time as it will straighten out in the end.

Fig 1

1) Building ‘On The Spine’. Also know as ‘The Preferred Plane of Bending’, or ‘The Plane of Least Resistance’.

The ‘spine’ is a feature of the manufacturing process of graphite blanks. This ‘spine’ gives the blank a ‘Preferred Plane of Bending’. The completed fishing rod will naturally want to bend along this ‘Plane of Least Resistance’ and if the rods guides / rings haven’t been aligned along this plane, then the problems start.

Factory rods could be built On The Spine, but they’re not because of us, Joe Public. When we buy a fishing rod at the local tackle shop, most of us sight down the rod with the rings either pointing straight up or straight down, and if the rod has a bend or kink we will reject it. If the rod looks straight then it’s OK. Rod manufacturers know this, and are forced to build their rods looking straight, and only occasionally is the ‘Plane of Least Resistance’ and the Straight look at the same place.

A straight blank is a very rare thing indeed, it’s almost impossible to get them, because of the nature of the materials and techniques involved in the manufacturing process. Graphite blank manufacturers would be out of business very quickly indeed if they could only sell true, straight fishing rods. What they have to do is sight down the blank and place the rings at the position that looks the straightest, so when you look down the rod, it looks fine.

You can test your own rods at home, ( see fig. 1 ) just take the tip section and stand it up straight and place the palm of you hand on the tip ring and push down carefully ( at your own risk ) to create a bend, and see the rods ‘Preferred Plane of Bending’. If the rings are straight on the bend ( see fig. 2 ) then your lucky, and if not, then you have a normal rod. This is a very basic way of testing and isn't that accurate, but it give you an idea. The pro will flex roll the blank to feel the kick points whilst loading the blank to near maximum because the spine can curve around the blank, complicated ha !!!

Fig 2

So why am I telling you this.
Well if you think that your rod is straight then think again, because if you turn the rod round whilst sighting down it, ( see fig. 3 ) you will see that it is most likely to have a kink or a bend, slight as it may be, but just not along the line of the guides / rings. If it has no bends, then have it stuffed and mounted on the wall for it is a rare beast indeed, but not unheard of.

Fig 3

So What am I getting at.
Well as we, Joe public, are already buying rods that have bends or kinks in them, ( which is perfectly normal as long as it’s not too pronounced ) then why not have them built on the ‘Preferred Plane of Bending’.

Why build on this ‘Preferred Plane of Bending’.
Well, what would you prefer, unloading that 90+ yard cast, and seeing your rig land on perfect target ( providing you have the ability to be accurate in the first place ), or see your rig going out of line and landing in the ‘dead zone’ because of KICK.
This is quite difficult to explain simply, but as we wind up and cast ( see fig. 4 ) we normally hold the reel upwards and this might not be in the same direction as the ‘Plane of Least Resistance’ thus we are fighting the rods natural ‘Preferred Plane of Bending’.
This cannot be good for the cast or the rod, and in extreme cases this fighting between you and the rod in the casting motion can cause the blank to torque twist, and possible failure.

Fig 4

Fly rods are often custom built to take the ‘Preferred Plane of Bending’ into consideration, because the cast is a very important part of fly fishing. I think, albeit not as important to the coarse rod world, it should still be important enough.
If you are paying out hard earned cash on a rod then why not have it cast and play, oh so sweetly.

2) Size of Rings.
I’m about to open a can of worms on this subject. In my opinion, sometime ago, some bright spark had a wonderful marketing idea to sell more rods. This was to have 5 intermediate rings on a carp rod instead of the standard 6, make the rings oversized and call it a ‘distance rod’. The whole idea was: less friction = more distance.
The reality is:
a) The decrease in friction caused be 1 less ring is almost un-measurable.
b) This decreases the rings affect on compressing the rod, thus making the cast even worse.
c) The increase in ring size, lifts the line further away from the rod, thus increasing the current torque twist, ( if the rod hasn't been built on the 'Spine' like most arn't) and making the cast even worse again.

Shimano have a rod ( Tribal XTR ) that is using the low rider guides from Fuji. Time will tell if we the casters will go for this small ring style. Most of us like large rings and as long as the rod is built on the spine then there seams to be no disadvantage to this. I'm sure in the future, this will be a subject of great debate by those inclined. A good casting style will get far greater distance than having big rings.

3) Ring Spacing.
Ring spacing is dependent on the rod action.
There is a graph method for placing the rings, this works well on the ‘Through’ to ‘Medium’ action rods but needs some minor adjustments in the ‘Fast’ to ‘Ultra Fast’ rod actions.
The key is placing the butt ring. Too far from the reel affects action and line flow ( slap ), and too close increases the angle that the line meets the butt ring at, and increases friction.

So if your around the bend, like me, you will now have a better understanding as to why some rods cast and play so sweetly and others kick like a mule. If your spending good money on rods, I think it’s worth looking at the Custom Option to get the bend right, let alone all the choices on the look of the rod. To elaborate on the choice’s, a factory rod maker would have to make approx 15000 different models to equal my workshops range, and that’s just the carp rods.!!

Tight Lines and good bending.