A Zeppelin bend is a general purpose bend knot.
It used a secure, easily tied, and jam-resistant way to connect two ropes.
Though its simplicity and security may be matched by other bends, it is unique in the ease with which it is untied, even after heavy loading.
Zeppelin bend is both strong and secure knot.
Zeppelin bend, Rosendahl bend, Rosendahl’s knot.
1. Form a loop in each of the ends of rope.
2. Overlay one loop on the other, such that the working end of each rope faces “outwards” or away from the other hitch.
3. Pull either loose end once around the loop in the other rope, and then through the “tunnel” created by the two hitches.
4. Repeat with the other loose end.
5. Pull on all four rope parts to tighten the knot.
Both names for this knot stem from its use to moor airships: a Zeppelin being a rigid-bodied type of airship,
and Charles Rosendahl being the US Navy officer who insisted it be used to moor airships under his command.
I found Zeppelin bend/loop probably as the most underestimated knot. Also simple geometry but probably awkward tying makes it to be forgotten.
I suggest tying bend the same way as Zeppelin loop.