Winter fishing for carp can be quite challenging due to the colder water temperatures and the carp's reduced activity levels. However, with the right approach and rig setups, you can increase your chances of success. Here are a few effective carp rigs for winter fishing:

Snowman Rig: The snowman rig consists of a buoyant pop-up boilie positioned above a sinking boilie on a hair rig. This presentation mimics a snowman shape, where the larger, sinking boilie sits on the bottom and the pop-up boilie hovers above it. This rig is effective because it offers a subtle, slow-sinking presentation that carp may find hard to resist in cold water. The best snowman rig to use is the blowback rig in my own personal opinion

Balanced Bottom Bait Rig: This rig involves using a critically balanced bait that sinks slowly to the bottom. It can be a standard boilie or a snowman-style setup. The key is to adjust the buoyancy of the bait so that it sinks very slowly or hovers just above the lakebed, making it an enticing option for lethargic winter carp.

Solid PVA Bag  Rig: Fishing with a PVA Bag requires a short rig usually around 3 to 4 inches in length, this rig is then placed in to your pva bag along with your tasty free offerings. The idea with the short length is that it only requires minimal movement from a fish for the rig to become tight to the lead causing the bolt effect. By using a PVA bag you are only offering enough free bait to entice a bite. 

Hinged Stiff Rig: This rig provides excellent hooking potential and works well in cold water conditions. It uses a stiff hooklink material with a hinged connection to the hook, allowing the bait to sit away from the lead or feeder. The stiff material helps prevent tangles and ensures the bait is presented effectively. A alternative to the Stiff hinge rig is the very effective Ronnie or Spinner Rig

Combi Rig: This is a very versatile rig that can be used all year around. Because of the mix of materials used, the stiff section ensures your rig is presented perfectly yet the supple section makes it very hard for a Carp to eject, a added bonus of the supple section is that when used with a Wafter or Pop Up bait the soft section will create a hinge allowing the bait to sit on top of any debris

Single Hookbait Presentation: Sometimes, keeping it simple is the key in winter. Using a single, well-presented hookbait, such as a pop-up boilie or a dumbbell, can be effective. This rig eliminates the competition from multiple baits and offers a focused target for carp to investigate.

Remember, during winter fishing, the key is often to downsize your tackle, use smaller hooks, and opt for more subtle bait presentations. Also, be patient and adapt to the changing conditions. As carp behavior can vary based on the specific water body you're fishing in, it's a good idea to experiment with different rigs and approaches to see what works best on your chosen venue.