The length of the hook link will need to be different for many carp fishing situations. It’s not just a case of tying on any old carp rig and hoping for the best. I think it’s important to think about the fishing situation and then adapt the length of the rig to suit that specific situation. It is also a good idea to spend some time looking in the margins to see how carp feed in the lake you’re fishing. Not all strains of carp feed the same way, and there are clear differences between fish in the same lake.
Normally I would use shorter rigs if fishing over a heavily baited area. This is because carp have less distance to move before finding another bait, so a short link will allow the hook to hit the weight of the lead sooner and helping to set the hook. Anything from 2 inches to 5 inches would be ok for fishing over beds of bait.
When fishing single hook bait tactics, or with a couple of stringers, I generally use longer rigs from 8 inches right up to 18 inches in length. The longer links have more natural movement and I find they produce more takes. However, it’s important to have some kind of stiff link material somewhere on the rig set up in order to limit any possible tangles. Long braided hook links are much more likely to tangle unless placed in a PVA bag or used with any other technique for stopping potential tangles.
Usually on pressured waters, it is often best to use longer hook links and fishing rigs. The more cautious a carp feeds, the longer the hook link needs to be. I remember reading an article by Lee Jackson, in which he discussed how the carp in a very well-known pit used to tackle rigs. He stated that they seemed to pin their lips to the bottom, and around the target bait, and only then attempt to suck the boilie up. If the bait was attached to a rig, the link would be trapped between the lake bed and the carp’s lips, which meant that the bait couldn’t be sucked into the back of the mouth. This was the way the bigger carp in the lake was “testing” rigs to avoid capture, and possibly one of the reasons why that particular gravel pit was known to be difficult.
In a situation where carp are testing baits as in the story above, you need to create a rig to suit the way they feed which will fool the carp. This is one reason why I like to use long supple braids wrapped and coiled up inside PVA bags, and then fill the bag full of small pellets. As a cautious feeder sucks at the group of bait, the link uncoils and extends right back into the carp’s mouth. Small pellets are used so they are light and won’t trap the movement of the braid as the fish sucks at the food. I have caught numerous big carp using this method, and with longer hook links than normal.
I have found that longer hook links are better for catching bigger carp. A longer link gives more natural movement and so has the potential to fool the bigger fish into taking the bait. Another reason why I believe longer rigs may work well is that bigger carp usually have larger bellies which hang down, and this means it’ll have to up-end further when feeding to avoid catching its huge belly on the bottom. Once it has picked up the hook bait, it needs to straighten up again to sample it. The extra length needed for a big carp to pick a boilie up and straighten means that longer links would better suit the way this large carp feeds. Also, some large carp suck up food items from a further distance, in some cases up to 4 inches away, a longer link will have the ability to extend and reach to the back of the mouth allowing more room for the hook to turn and grab hold.
If you fish in silt, or silkweed, then the hook links should generally be longer. If the lead sinks into the bottom or drops through the weed bed, the hook bait can still rest nicely on top for a good bait presentation. A longer link decreases the chance that the boilie will be dragged into weed.
If fishing in-between weed beds on small, clear patches, then I would recommend using shorter rig lengths as a longer link may cause the lead to land on the clear gravel but the hook caught up hanging in weed and exposing the lines.
On gravel I would say it doesn’t matter too much about the length of rigs. The main thing is to make sure all the line is pinned down on the bottom. The last thing you want on a flat gravel patch is to have the carp bumping their fins into your line.
Another way to find out what’s the best hook link length to use is to try various sizes of the same carp rig on different rods whilst fishing for carp. If a certain length on one rod outperforms the other two, then change the other rods over to the length that’s producing the most runs. As a general guide, if the hook is positioned on the edge of the lips when you catch a carp, then the link may be too short. If the hook position is in the middle of the bottom lip, or an inch or two further back in the carp’s mouth, then it is the correct length!
One final point I would like to make about the length of fishing rigs. Always try to find out what many of the other anglers are using on the lake, and then create a carp rig with a different length to the “norm”. Carp will often adapt to rigs, and this also means they’ll learn how to deal with a certain length of hook link. Using a different length, or type of rig, to what other anglers are using means you’ll often be one step ahead of the carp in your local water!