Which type of splice would be most suitable in a situation where line diameter needs to remain small?

The most suitable splice in a situation where a line diameter needs to remain small is the short splice. A short splice joins two ends of a line together in such a way that the finished splice creates only a slight increase in the line’s overall diameter. This is achieved by tucking the strands of the two lines together, which minimizes bulk and makes it ideal for applications such as when the splice needs to pass through fittings or be run through a block.

In contrast, a long splice, while also a method of joining two lines, involves more extensive interweaving of the strands and therefore increases the overall diameter more than a short splice. A square knot and a sheet bend are not splices but rather knots, used for tying two lines together rather than splicing, and do not offer the same structural integrity or minimal increase in diameter as a short splice. Thus, in situations where keeping the line's diameter minimized is critical, the short splice is the preferred choice for its effectiveness in maintaining a streamlined profile.