Oystermans stopper
Sometimes a bulky knot is needed at the end of a rope to keep it from slipping through a tight space. This knot creates a flat triangular shape that is thicker than most other knob knots.
Start with a basic slipknot. Note that the part of the knot that slides is toward the standing part of the rope, not toward the end.
The final knot will rest flat against a horizontal surface. Here you see the general form with a ‘bump’ on the left and the right.
From the top, the two ‘bumps’ of the slipknot are seen at the top and the lower right. All that is needed now is to add one more bump at the lower left.
Bring the end of the rope around to the opposite side of the loop.
This has created the third bump. Now to hold it this in place simply tuck the end through the loop.
Now the triangular shape is clear, with the end of the rope sticking out to the side.
From the under side of the knot, the triangle shape is clearer.