The Somerville Bowline might be the most popular column tie among serious riggers. It’s a subtle tie that is hard to learn, but it has numerous advantages compared to the basic single column tie:
The biggest disadvantage of the Somerville is that it can sometimes jam when it’s been under heavy load.
The Somerville is one of a family of ties invented by Topologist, who has a set of excellent articles and videos about them.
1Place your left hand palm up over your left thigh, with the middle and index fingers extended.
2Make two counterclockwise wraps around your left thigh, leaving about 8" of bight.
It is important that the rope travels over your middle finger and then your index finger, not the other way around.
3Wrap the standing end of the rope in a counter-clockwise loop under your middle and index fingers, behind the bight, and over itself.
Note that at the base of the loop, the rope now makes an X shape where it crosses itself.
4Flip the bight over so that it passes over the X shape.
5Pass the bight under the wraps and up through the loop that you made in step 3.
6Pull on the bight and the standing end to snug the knot.
The Somerville Bowline was created by Topologist, who has an excellent video tutorial of it at fullcirclekink.com/x120