I've been using a trucker's hitch knot for a very long time (camping, strapping stuff down, line length adjustment, pulley system) I've always switched my mid-line loop when I've come to not trust them for numerous reasons (not secure, impossible to untie after loaded, rope damage, take too long, etc...).
Here is an example http://www.animatedknots.com/truckers/
This one is tied using a directional fig 8 as the mid-line knot.
I've used the following knots for periods of time, switching between them as I feel uncertain:
- slip knot (quick, not reliable)
- alpine butterfly (quick, reliable, seizes up)
- directional figure 8 (quick, reliable, seizes up)
- sliding prusik (doesn't seize, not quick if not already on rope, sometimes not reliable)
- bowline on a bight (reliable, doesn't seize, not quick)
- span loop (reliable, quick, seizes up)
- "half" sheep shank with a half hitch to secure also called a bell ringer's knot (quick, doesn't seize, reliable?)
They all have their uses and advantages but I'm looking for that 'bomb proof' setup where I can load it to the max that the rope can handle and still be able to hold while not making this mid-line knot impossible to remove and doesn't permanently damage the rope. Speed is important as well because I will often pull out my cordage and tie down a trailer full of stuff while my Father/Father In Law will be fiddling with straps that have a tendency to become a nightmare of a mess.
My go to was a directional figure 8 for the longest time but it started to get very difficult to untie when using heavy loads (I'm heavy and like to use hammocks while camping :) some of my cordage has these in there permanently). I then switched to using the span loop for a long time but that also locks up. I've now settled on a bell ringer's with a half hitch lock.
This has worked well for me when tied properly but it 'feels' like it is not secure. I've never had it fail (even on 6 hours trips being used to tied down kitchen appliances on a trailer) but it just doesn't seem like a very stable setup.
What knot is best suited as the 'fixed' knot in a trucker's hitch?