I think that's a pretty clear indication that in order to hold in Dyneema, a knot needs high nip, not additional crossings. Toward that end, I evolved a dirt-simple, ugly bend with multiple nips that is straightforward to tie and easy to remember. Initial testing suggests that it is secure and possibly the strongest one yet. I want to try some variations next and I'll post pictures when I get a chance.
Here is a very simple bend with lots of nip but without many crossings. As illustrated in the first image below:
- Start by putting three overhand knots in the end of one piece of Dyneema. Put one overhand in the other. Leave plenty of tail on each (this knot swallows a significant amount of tail when drawing taut).
- Pass the working end of each line through the last overhand of the other.
- Make an overhand knot between the two middle knots (around the other line) and pass the working end through the adjacent overhand.
- Repeat the last step
Dress the knot snugly as shown in the second image. All the overhand knots shown were tied right-handed and the crowns are aligned. You can see that in the views of the two sides. This bend could be made symmetric side-to-side by alternating the crowns. I doubt it would make a difference in security.
Note that each working end is nipped by the other standing end. This is vital to the security of the bend. If the running ends nip the standing ends, then the knot may slip.
The third photo below shows the bend after placed under load; and having been loaded to the breaking point. You can see that four central overhand knots drew up into two separate Water Knots (ABoK 1414). The distance between them indicates how much tail was drawn into the knots as they tightened. If you don't leave enough tail when dressing, this bend will pull apart.
This bend gets its security not from multiple crossings, nor from u-turns, but from each end having three good, hard nips on the other. It may not be pretty, nor compact, but it is straightforward to tie and easy to remember. This bend appears to be roughly equivalent in strength to my earlier "Twang Bend".
I tried substituting Strangle Knots (ABoK 1239) for the Overhand Knots, and was able to get by with four nips instead of six (although it swallowed more tail drawing up). I don't personally see much benefit to the strangles. The regular overhands are more straightforward to tie and I'd trust 6 nips more than 4.
I hope you like it,
Eric