The End Game

Simon Chu weighs up monofilament and fluorocarbon

Unfortunately I had to lose another fish before I decided my nylon tippet was ‘rotten’ and needed to be thrown away. We’ve all been there. Spent the money and had the best equipment, only to let ourselves down with poor terminal gear choices. Whether it is flies tied on cheap hooks or persevering with degraded nylon — we know we can change. It’s just a case of doing so. This episode led me to research a bit more about nylon and how it is different from fluorocarbon line — why might I choose one over the other and the advantages and disadvantages of each. Wallace Hume Carothers, an American chemist at DuPont, is credited with the invention of nylon in the 1930s. Nylon soon replaced ‘cat gut’ and silk and found its way into fishing applications soon after. However, Kureha in Japan didn’t patent fluorocarbon until 1969, and then in 1972 ‘Seaguar fluorocarbon’ was launched to anglers at the Tokyo fishing show. The science of construction wasn’t perfect, with criticism over knot strength and clarity. It wasn’t until the 1990s that fluorocarbons really secured a place in fishing. Nylon or monofilament is simply an extruded piece of plastic. It is generally the cheaper material of the two and is credited with having a physical life-span of 600 years! Mono by definition is a single strand but may also now be marketed as a copolymer. This is a blended nylon seeking to enhance the abrasion resistance, translucency and elements of stretch in a line. This is in contrast to the multiple structured fluoro, which at the premium level has several resins to enhance performance and knot strength. Environmental impact Nylon’s environmental impact is undoubted and every year countless birds, fish and other creatures are entangled and trapped in discarded nylon. It also requires three times more energy to produce than does cotton! Fluorocarbon is even worse and has a reported lifespan of thousands of years. Our responsibility to secure and dispose of waste leader and tippet is more critical than ever. Water absorption Fluoro lines do not absorb water and this is one of the significant differences for an angler when considering fishing applications. When completely saturated, simple nylons absorb as much as 10% of their weight in water and although this increases suppleness, it also decreases dry breaking strength. It has been reported that breaking strength may decrease by as much as 20% and as the diameter of the nylon swells the long term effects will be a degradation of breaking strength, particularly at the knots. As fluorocarbon lines do not absorb water the effects of water on its physical properties are minimal. However, as anglers know, the knot may be the weakest point in our connection and with fluoro the seating and sealing of the knot is critical to avoid slipping. Wetting a knot or using lip balm to lubricate it can often help. As its dry physical form remains the same, fluoro may also retain some of its stiffness even when wet. Note that some of the premium nylons are treated to decrease absorption as well as to improve UV degradation and abrasion resistance. Elasticity and the effects of stretching Nylon’s elasticity is also greater than fluoro. This means that after being stretched under load it eventually returns closer to its original length, whereas fluoro when stretched in the same manner does not — it often stretches minimally and then remains at its post stretched length. Continued swelling and repeated elongation of nylon will eventually lead to a decrease in breaking strength. I believe this happed to my spool of nylon as, over the course of a few months it had been thoroughly wet several times in my pocket during deep wading adventures. Although dry when I used it, I believe it had deteriorated and I should have discarded it for a new spool. Knot strength was noticeably weaker and I had lost a number of fish on the strike. A good reason to change spools at the start of each new season! In a fishing context, this reinforces the need to change tippet and leaders regularly. Perhaps we are guilty of not changing tippet after a prolonged fight only to lose a big fish on the next hook-up. Abrasion and stresses from being stretched, abraded and/or waterlogged will lead to tippet failure. In contrast, however, some anglers will actually boil and soak leaders to enhance the properties of elasticity, and use nylon as a shock leader. I have known competition anglers and those chasing records to do this to increase the stretching properties of their leaders. As opposed to using the superior properties of nylon for shock absorption, hard coated nylons and fluoro provide better abrasion resistance as shock leaders against teeth, gill plates and terrain. The stiffness of fluoro may also assist in casting accuracy (stiffer for turnover) but the suppleness of nylon may allow the dry fly to drift more naturally. Ultraviolet degradation Always purchase nylon that has been displayed at the back of the store. If you are asking for the spool displayed in the shop window, be prepared for tears when you break off a fish no matter what the discount price. Ultraviolet light breaks down nylon and may significantly decrease its breaking strength. Combined with stretching and swelling, ultimately this may lead to a much weaker tippet than you had in mind. Of course a day’s angling or even five would not result in a sudden decrease in performance but leaving a spool on the dashboard of your car all day or continuous exposure to sun on the outside of your vest may surprise you. Again, fluoro is relatively impervious to UV light, and combined with the lack of water absorption and reduced elasticity, these properties are not compounded as happens with nylon. Refractive index and sinking rates Much of the marketing hype for fluoro revolves around the idea that it sinks faster than nylon and is invisible to fish. Refractive index refers to the speed of light as it travels through a material. Water has a refractive index of 1.33 while nylon and fluoro have values of 1.58 and 1.42 respectively. Without doubt the science doesn’t lie, with fluoro having a lesser value and so is theoretically less visible when light is passed through. Can a fish see the knot and leader? Undoubtedly. Would you get more hook-ups using fluoro? Perhaps… but my personal opinion is that the correct sized tippet material matched to the hook will give a better action to the fly. I know elite anglers who swear that by decreasing tippet diameter they will elicit more positive responses. Fluoro has a specific gravity greater than nylon. Specific gravity refers to the density of the material in relation to water and it may be as much as double for fluoro over nylon. This makes it more likely to sink, but unless it has broken through the surface film (dependent on angle of entry and the weight of fly of course) this will not be significant and there is minimal difference in sinking performance. From an angling perspective, it is more effective to assist the tippet to sink by applying sinking agents such as Snake River Mud or equivalent. If you want your tippet to float (perhaps as a sighter when midge fishing) Loon Payette Paste or even lip balm will keep your tippet in the surface film. Cost No question, fluorocarbon tippets and leaders are more expensive than nylon but not all nylon tippet material is created equal. When you purchase nylon tippet material consider the diameter and whether there are any additional coatings or additional treatments. Often that will add to the cost of a quality nylon or ‘copolymer’. Quality nylon (read higher cost!) will often be thinner. Tippet diameter is more important the smaller your fly. The X scale refers to tippet diameter and from 0X at 0.011 inches it decreases .001 of an inch with each increasing X class (i.e. 1X is .010 of an inch, 2X is .009 and so on). To get the best action on your fly, you want a knot that does not interfere significantly with presentation and action. Knot size is usually dependent on tippet diameter and as a rule of thumb you might use 3 times the X class for the hook size. For instance a size 18 fly would benefit from a 6X tippet rather than a 3X. However, depending on fish size and your thoughts on whether a fish even cares, you might choose otherwise. Manufacturers will nominate a different breaking strength in each X class and this is most likely the reported dry breaking strength (as it will always be greater), and depending on quality of nylon, the diameter will vary greatly between brands. I would suggest purchasing brands you trust and feel confident with when tying knots, then keep your spools from heat, sun and excessive moisture. Replace spools regularly but try new brands when you think properties such as diameter to strength ratio, abrasion resistance, hardness or limpness will add to your fishing effectiveness. Does it matter? So when and why would I choose one material over another and does it really matter? To answer the latter – yes it matters. Whether it is the quality of hook or tippet, this may be our last and weakest connection to the fish we have travelled half way around the world for and spent all that time learning about, let alone the money spent on gear to catch it. I prefer supple copolymer nylons when fishing small dry flies and am seeking a very soft presentation. I use nylon when fishing local streams or when I am using large quantities of leader, for example when employing European nymphing techniques. Otherwise, I purchase quality fluorocarbon. If I am travelling to a new fishery or invested heavily in the outcome I also like buying new spools! I prefer fluorocarbon for its abrasion resistance, lack of water absorption and UV resistance. Ultimately I want to catch and land all the fish I hook and I am more confident with fluoro. Although the cost of nylon might offer a slight advantage in value, I have learnt now that I should change spools each season for many of the reasons outlined above. Perhaps the price of fluoro becomes more comparable when this is considered. It is also a good reason to only purchase the small 30 metre spools. Most importantly, I should learn to tie excellent knots, seat them properly and ensure my flies are tied on good hooks. I should also retie my knots and change tippets after protracted battles with fish or flora. Elite angling is a result of reflective practices and ensuring we take every step to maintain our gear and our skills at their best. Also see Adam Royter’s article in FL#94 for more ‘Pointy End’ advice.

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