At least in my 3* class, we discussed possible methods to bring an unconscious victim up in the boat. Apparently, tying two ropes to the gunwale, passing them under the body and up again and then having two persons aboard haul the victim up is supposed to work. Sometimes. If you're lucky. And any boat should have a few meters of sturdy rope stowed away somewhere.
If the "body" isn't alive, all you need is a few meters of rope. Tie a bowline on one end, hitch to one of the aft cleats. Tie another bowline through one of the D-rings on the body's rig, make sure the rig is properly fastened and the BCD/wing bladder is properly inflated, and start towing.
This is of course both tongue in cheek and rather tasteless, but there are some scenarios that you won't be able to handle without outside assistance. Sometimes the only viable solution is to call emergency services, either on the phone or on channel 16 on the VHF and wait until they arrive to take over.