What type of knot can be used to join two ropes of unequal size together?

The sheet bend is the appropriate choice for joining two ropes of unequal sizes due to its design that accommodates different thicknesses effectively. This knot consists of a simple structure where the thicker rope is passed through the loop of the thinner rope, allowing a secure connection. The configuration of the sheet bend does not only provide strength against load but also allows the knot to maintain its shape despite variations in rope diameters.

In contrast, the water knot is typically used for joining two pieces of webbing or ropes of similar thickness and does not perform as well with unequal sizes. The figure eight knot is primarily used as a stopper knot or in climbing situations for securing ropes rather than for joining. Lastly, the bowline is advantageous for creating a fixed loop at the end of a rope but is not designed for connecting two ropes together, particularly those of different sizes. Thus, the sheet bend stands out for its specific utility in situations where ropes vary in thickness.