Carp Fishing Main Lines – Ultimate Guide to types of Main Line

Dave Fuidge believes the most important bit of kit we anglers use is our main line.

Our main line is our direct contact with the fish we spend a lot of time and money fishing for, and it is the one bit of kit that if not looked after or used properly will eventually let us down. I get asked questions about line from time to time: what’s the best line, how to spool it, and how much to use?

Let’s look at the last question first. I have always been the type of person that doesn’t like waste. It’s the same in my fishing. Unless I am boating baits out a long way, which isn’t very often these days, I only put a maximum of about 250 yards of line on my reels, even when long range fishing. This way one 1000m bulk spool will easily give me enough to do three reels, with plenty left over to respool one if necessary.

Spare spools with spool reducers – no more need for any backing line
The superb line lay of the Ultegra C14+ 14000 XT-B makes for a much easier and longer cast
The best way to spool up

For many years I use to back my spools with old line or buy a bulk spool of thicker line to back them with. These days I am using Shimano Ultegra C14+ 14000 XT-B reels and, amongst other features, they not only come with two spare spools but a host of clever spool reducers, so there is no more need to use any backing line. The three spools mean I can now spool up with three different lines to suit all the fishing situations I come across. Also the slow oscillation means a superb line lay and therefore a much easier and longer cast, and the reel only weighs 560g, which makes it a pleasure to use.

I am using two types of line at the moment: fluorocarbon and nylon copolymer monofilaments. Although these lines may look the same superficially, that’s where the similarity ends. Without getting too technical let’s have a look at the make-up and pros and cons of each.


Fluorocarbon is an extruded material made the same way as nylon monofilament, but has a totally different make-up. It’s made from PVDF (polyvinylidene difluoride), which is a true thermoplastic. The main advantage of this line is that it is almost invisible when submerged in water, thanks to its light refractive index of about 1.42, which is very close to that of water. This type of line is also very abrasive resistant, doesn’t absorb water and the fact that it’s denser than nylon makes it sink like a brick. It also has less stretch than nylon, which makes it good for bite detection, and it’s not affected by UV rays from the sun, so it doesn’t deteriorate as much as nylon.

There are a few things we need to watch. Firstly, if you are looking to cast a long way, and by that I mean over 100 yards, then most people will struggle. Fluorocarbon line is not very supple and those of you that have used it will know that it’s not the best behaved of lines. Also knot strength suffers; you have to be very careful and pull your knots down slowly, making sure they are wet. The best and only knot I use for this line is a tucked five-turn half blood knot.

I tend to use fluorocarbon when I am not fishing too far out and I want to pin the line down to the lake bed, especially when the water is crystal clear. When I have enough bank space, I stretch the line out; this helps it behave a little better when casting. After every session, and sometimes once a day on long sessions, I wipe the line down with a piece of kitchen roll. This removes all the grime and anything else that sticks to it. After all, it’s no good having a near-invisible line covered in algae or discoloured by anything else that’s in the lake.

At the moment I am using Aero Fluorocarbon, which comes in 500m spools and is one of the softest and best behaved fluorocarbons that I have found.

The lines I am using are tough, strong and cast very well

Nylon copolymers

‘Mono’, as we like to call this type of line, is made in the same way as fluorocarbon, the difference being these lines are made of nylon and other polymers. The main advantage of this type of line is the castability, because monos in the main are very supple, they will cast a long way and they tend to behave a lot better than fluorocarbon. The knot strength is a lot better than fluorocarbon and there are some lines out there that are very abrasive resistant. One point to make about these polymers is that they come in lots of different grades, some good and some not so good. As a rule of thumb, the more expensive the line, the better the quality of polymers used.

The main downside to monos is that most of them don’t sink very well. This is due to the fact that they are not much denser than water, and they absorb water at about 4% which makes them even less dense. I’ve had quite a few discussions with people over this. Even with a back lead, the line between the back lead and your lead will at some point float off the bottom, unless fishing just a couple of yards out. Just ask anyone that has been out diving a lake, they will tell you the same. To combat this, I use a fluorocarbon leader of about 20 yards, where allowed. This way I am happy that in the area around my bait the line is pinned down and as invisible as it can be.

I tend to use this type of line when fishing at range, anything over 100 yards. At the moment, I am using two brands, Technium Invisitec and the regular Technium. Both have only about 12% stretch, so bite detection at distance is improved immensely.

Unlike most people, I always go by line diameter rather than breaking strain for my distance work. I go down to 0.29mm (10lb), or if it’s a bit weedy I use 0.33mm (12lb). In the Technium, both these diameters break well over the stated breaking strains.


This is where it can all go wrong. There are many different theories on the best way to spool line. Some work and some simply mess the line up and put copious amounts of twist in it; that will damage the line and cut down your casting distance.

I have always spooled my line by taking it off the spool the same way it was put on. There are two ways I normally do this. The first is to put a pencil or piece of dowel through the centre of the spool and get someone to hold it, with their hands pushed slightly against the spool to cause a little tension. Then using the butt section of a rod, I will simply wind the line on to the reel. This way is all well and good if you have a helper.

If you are on your own and want to spool line then the best way I have found is, to get a bucket and half fill it with water, then get a piece of dowel and cut it just long enough so you can push it into the bucket sideways so it is tight against the sides. Again I then use the butt of the rod and spool up. This time, I will tension the line with either a piece of sponge in the eye or using my fingers as I reel.

A couple more things to remember:

  • Always soak your line before spooling. This will help to make it more supple and go on the spool better. I usually do mine for about 24 hours.
  • Always clean the line. This doesn’t take long and it will prolong the life of it immensely. By doing this, you can also check the condition and if you need to change it. It’s no good sitting there for hours or days, only to find the line lets you down. It’s not just the case of losing a fish, which is bad enough, but the fish will be trailing unwanted line and that’s not good angling.

I hope this has helped. By spooling your line properly and looking after it, you could put extra fish on the bank.

Big fish in clear water – a perfect situation for fluorocarbon line


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