Convert from cape foot to X unit

Unit Definition (cape foot)
The cape foot is a traditional unit of length in South Africa. The Cape foot equals 12.396 English inches, 1.0330 English foot, or 31.4858 centimeters. This unit is not the traditional Dutch foot, but it is similar in length to the "Rhine foot" of northern Germany. The Cape foot was widely used for land measurement and appears on many deeds in South Africa. Europeans often referred to South Africa as "The Cape," meaning the Cape of Good Hope.

Unit Definition (X unit)
The X-unit (symbol xu) is a unit of length formerly used to measure the wavelength of X-rays and gamma rays. The X-unit is approximately 1.0021×10-13 metre. Defined by the Swedish physicist Karl Manne Georg Siegbahn (1886-1978) in 1925, the X-unit could not at that time be measured directly; the definition was instead made in terms of the spacing between planes of the calcite crystals used in the measuring apparatus.