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Chapter Three - TEST CURVES

In many ways "action" and "test curves" are so closely related that inevitably there is an overlap regarding blank design. To try and get to grips with the subject, it is important to understand the basic principal from which a general rule of thumb has been used by the industry for a long time.

The phrase "test curve" is a description that is used to calibrate how much weight is required to pull a given rod blank tip 90 degrees to the butt. The blank would be fixed horizontally and weights fixed to the tip until the 90 degrees are reached, Whatever total weight, in pounds and ounces, that is required to achieve this, is the "test curve".

The problem is that nowadays there are so many different types of carbon being used that there isn’t a level playing field. If only one material were to be used by everyone in the trade, and only one length of rod, evaluation would be very uncomplicated, but there are so many variables.

In addition to the variables in materials and length, blanks DO vary from one to another for a whole host of reasons. One example is the difference between an un-ground blank and a ground, "painted" blank. This does not necessarily mean that a painted blank is weaker than an unground blank, because the makers actually allow for this. There is quite often a difference between the two though. Not withstanding that, in my opinion, there could be a variance of plus or minus 10% in the performance of a batch of blanks, caused not just by this difference, but by other potential factors that the blank manufacturers find impossible to control. Please understand that these variables are not usually enormous, quite the opposite, but they do exist and they do have effects on the overall performance, including test curve.

Another example worth considering is this, the mandrels used are always longer than the pattern of carbon tape which will be wrapped around them, and it does happen that blank makers wrap a little higher or lower on the same mandrel sometimes creating a variance. Likewise there could be variations in the wrapping pressure. These and possibly many other examples will have effects on the overall performance of the blank. Once again I have merely touched the subject of variation of the blank, it would be quite possible for me to cite many more examples of variation.

If we are to use "test curve" as the criteria to gauge the suitability of a blank or rod we must decide on what length of rod we want. An 11 foot 1 ½ lb. t.c. Rod will feel stiffer (more powerful) than a 12 foot rod of the same test curve that has been built using the same materials and assuming that the handle position is more or less the same on both rods. But because we have changed the position of the fulcrum the whole dynamic has changed, so the longer rod will be slower to reach it’s test curve, this gives the impression that it is "softer" or less powerful. It isn’t in fact; it just takes longer to reach its test curve potential. This is why "snag" or so-called "stalking " rods are short. The short rod enables the angler to exploit the power of the rod really quickly.

If we are going to order a blank to build a Barbel rod on, I believe the first thing to decide is, which length is preferred. I have to say that I would not want a 12-foot rod. In my opinion, and once again this is a personal viewpoint, I honestly believe that I can fish more efficiently with an 11 foot rod. I can hold the shorter rod for longer and it will be better balanced. Even if I put my rod in a rod rest, I can strike utilizing the power potential quicker, and get in control faster too. Again it is a fact of dynamics that it is easier to move a shorter stick quicker through the air than a long one!

Having made the decision with regard to the length of rod that is required, how do we decide what test curve blank to choose. This depends on a number of factors. For example, "where will I be fishing?" Will it be a big deep river with a real "pull" to it, or a shallow narrow river possibly overgrown with lots of snaggy areas nearby. Two very different rivers and therefore two sets of circumstances that will dictate or at least have a great influence on the final choice of rod or blank.

Let us now consider another aspect of the test curve rating system. I am sorry but again the following comments are slightly less valid than they were a few years ago, but it is all we have to go on.

The stated test curve, by applying the following, easy to understand formulae, will enable us to match the right line range for the rod. Example, if a rod is rated at 1 lb. Test, multiply that figure by five (1 x 5 =5).

Then add or subtract 30%, (5 + 30% = 6.5) or (5 – 30% = 3.5) we can see that the rod will handle lines from 3 ½ lb. b.s to 6 ½ lb. b.s. So if you are using a rod of 11/4 lb. t.c. With 10 lb. b.s. line you are in fact overloading the rod by 1.88 lb. Does it matter? Well it would if carbon were not as strong as it usually is. If you leant into the rod in the days of fibreglass or even bamboo, you could easily have broken the rod if the line had not broken first! These days our rods are very much stronger size for size. However, if we are intent on getting our presentation dead right we may well have to consider the range of lines suitable for our rod. Fish too fine and we will surely be broken, fish with a line to heavy and apart from possibly overloading the rod, we will loose some presentation advantage. Once again lots of variables!

So how do I choose the right rod then you ask? Well this is not an easy question to answer. This is how I go about it. I have previously stated that a rod is expected to perform 3 jobs. To recap these are, casting, striking and playing fish. I will now add another that to me is of equal importance, bite detection. I want to, in most cases FEEL the bite, and I want to SEE the bite. So I want a certain amount of tip flexibility. I want to strike quickly and positively. And I want to be able to control, to some degree, the Barbel that I hook.

My rods then will be on the moderate side of "fast action" but with a power reserve requirement that is adequate to subdue the biggest Barbel that I might realistically hook. I will also give thought to what size of lead that I might have to use. If a 4oz. lead was the requirement (God forbid I hope it never is!) then I would have to look again. And we would be getting deeply into "very specialized" rods now. Another two pages at least would need to be written, to do THAT subject justice and I don’t think I want to do it – yet!

So for most Barbel fishing, rods of 1 ¼ lb. t.c. To 2 lb. t.c. 11 foot or twelve foot, that must be your choice. But do consider a moderately fast action rod/blank. Although I have stated, more than once that my favourite rod is a Harrison Avon, the best all-round Barbel blank available is the 11 foot GTI Carp 2 lb. tc.by Harrison. There I have finally said it! Next installment, blank alignment".