Which knot is preferred for connecting two lines of unequal diameter?

The sheet bend is the preferred knot for connecting two lines of unequal diameter due to its ability to securely join ropes of different thicknesses and materials. This knot has a simple design that allows it to handle loads efficiently and is less likely to slip compared to other knots.

When tying a sheet bend, the thicker line is used as the base and the thinner line is passed through the loop created by the thicker line before being wrapped around it and tucked back through the loop. This structure provides added grip, making it effective in various scenarios, such as when joining a thicker anchor line to a thinner working line.

Other knots like the square knot are not suited for this purpose because they perform best with lines of similar size and can easily slip or come undone if under load. The figure eight knot is primarily used for creating loops in lines rather than connecting two different lines, and the round turn with two half hitches is more suitable for securing a line to a post or object rather than joining two different diameters together.