Early detection and avoidance are the best way to deal with strainers. Be very aggressive in steering clear of strainers. If you come across a strainer that can't be safely avoided, ram your boat ashore upstream if possible and get out. If swimming with your boat and it looks like you can't safely steer the boat away from the strainer, push off the boat and swim quickly away from the strainer.

Assuming you can't avoid the strainer, the typical defensive swimming approach - feet downstream with a back stroke will not work. Once your feet go under the strainer, the rest of your body will do the same. The best approach is to face downstream in an american crawl, swim aggressively towards the strainer, launch/push your body over the log and kick hard to get the bottom half over the strainer. Sometimes you can climb a strainer pile if there are a number of decent hand and foot holds. Do whatever you can to prevent any part of your body going under the strainer. In the ACA SWR class, we practice this technique with an artificial PVC pipe strainer. Here is an excellent video demonstration of this drill: Strainer Drill.

Entrapment can be avoided by staying away from strainers, sieves, undercuts, and proper swimming techniques if you come out of your boat. Don't try to stand in fast current up to your thigh area, chances are you will get swept downstream out of control. If you have an older boat, make certain the walls are very secure so it is unlikely to collapse. When purchasing a boat, make certain it has a full bulk head for your feet instead of foot pegs that were common on older boats. Make certain throw ropes are stored properly and carry a rescue knife in an easy to get at position on or in your PFD. Just like skiing, stay in control. If the run is too difficult, portage the tough rapids or walk out if necessary. Here is a good article describing foot entrapments: Foot Entrapments.

Extrication often requires hands on contact by a rescuer (e.g., two+ person wading techniques, live bait)

A good rule of thumb is when the current is strong, swim instead of wading when over knee depth. Entrapments in fast current are very dangerous indeed. Boaters can only hold themselves upright for a very limited period of time before their upper body strength gives way. For these reasons, rescues often involve getting a boat or person out to the victim ASAP which may place them in danger.

Entrapment can be avoided by staying away from strainers, sieves, undercuts, and proper swimming techniques if you come out of your boat. Don't try to stand in fast current up to your thigh area, chances are you will get swept downstream out of control. If you have an older boat, make certain the walls are very secure so it is unlikely to collapse. When purchasing a boat, make certain it has a full bulk head for your feet instead of foot pegs that were common on older boats. Make certain throw ropes are stored properly and carry a rescue knife in an easy to get at position on or in your PFD. Just like skiing, stay in control. If the run is too difficult, portage the tough rapids or walk out if necessary. Here is a good article describing foot entrapments: Foot Entrapments.

Foot entrapment rescues can be really dangerous. A combination of a stabilization and snag lines may avoid a hands on rescue but this is very tricky to pull off, especially the weighted snag line. Another alternative is the saw method. Run a line at water level downstream of the victim. Wade into the deeper water on both ends and pull back and forth pressing downwards. This approach is much faster and has a higher chance for sucess than the weighted snag line. Most of the time, someone needs to go out to the victim. Be very careful with footing so you don't fall into the same trap. Use a rescue vest and secure a line to your tether as an extra safety precaution. Stir the bottom with your un-weighted foot to find the next safe place to plant your foot. If it grabs it should be easy to pull back out. Once you make it to the victim, you should be able to pull out an entrapped foot fairly easily. To unpin a boat, have someone hold the victim's body to stabilize and try to back out the boat or loosen one end depending on the pin.