'The Book of Acts was originally written in Koine Greek, defined as Alexandrian, Attic, Hellenistic or biblical Greek. “And sounded and found it twenty fathoms, and when they had gone a little further, they sounded again and found it fifteen fathoms.” (27:28) Fathom is translated from the Greek orguia. One of the definitions of orguia is outstretched arms, as is the definition of the old English derivative of fathom. A fathom is presently defined as six English feet, although a previous British Admiralty definition was 1/100 of a cable, or 1/1000 of a nautical mile, equal to 100 ancient Egyptian digits, or one orguia, or six Attic feet, or five remen, or 1/1000 of a minute of latitude.'
The standard definition of the ancient Greek orguia is outstretched arms or six Greek feet, but the context of this verse shows that it was also regarded as a fathom in the modern understanding of the word, and may suggest it was also regarded 'as understanding', or knowing, or plumbing the depths, another definition of 'fathom'.
I came across this verse while doing some research on fathoms after looking at de Lubicz' comments about the fathom being the arc of the 1/6 chord of the circle and how the arc has a pi/6, or .5236 relationship with the diameter of the circle. If we take the Greek foot as the arc, which would then give the orguia as the circumference, then 12.15 inches/.5236 = 23.2 inches/2 = 11.6 inches for the radius, which is pretty close to the Roman foot (or the Egyptian foot based on 16 remen digits), but not quite close enough, particularly since these measures are all interlocked by the ancient Egyptian digit.
I also looked again at some of the other things de Lubicz says, including some of his comments about volume:
"Among the things I have learned there are some that are more dangerous than beneficial to divulge, but it is not possible for me to discriminate in this matter, for the preparedness of each individual, which opens or seals his or her eyes, must be the sole judge." p.1
"In the preceding pages I have often alluded to volume in explaining, among other things, the 'intellegence of the heart' as a synthetic vision in volume, in maintaining that the first perceptible aspect of the Universe (the Creation) can only be spatial, and also in referring to volumes in connection with sound and harmony.
In contrast to how we arrive at volume (from the bottom up) by the supposed movement of point to line, line to plane, then plane to volume, the Ancients begin with volume, from which proceed their own definitions of surfaces (planes), edges (lines), and vertexes (points).
It is then essential that their calculation use volume as its starting point, their unity being this volume. This is difficult for us to gain access to through our mode of operating, for our scholarly method, with its imaginary elements, arises from a position opposite to that imposed by reality.
As a continuation of this study, we are going to indicate here the way to proceed in order to understand one of the profound meanings of the fractional system, and the importance of the fractions 2/3 and 1/3, so as to catch a glimpse of the simplicity of the means used for defining square and cube roots, all of which is founded on the principle of harmony. Since harmony is, by definition, the cosmic order, which, in breaking apart always and inevitably, through affinities, puts itself back in order once again, it was thus by obeying the laws of harmony that the pharaonic masters were able to establish a system that, while being particular, keeps its universal quality." p.250
"We have not found any mention in the history of ancient mathematics of the practical, simple, and rapid method for extracting cube roots as described here. It was inspired by Babylonian mathematics but results from the totality of our studies of the ancient methods." p.271