BRACE
This measure of Greek origin is still used in marine environments. Both arms were used extended in the shape of a cross, and the fathom is the dimension between both ends.
The sailors who crewed the ship put the probe into the sea to find out the depth and gave the measurement in fathoms.
The fathom was equivalent to about 1.85 meters (Acts 27:28). The measurements vary somewhat. The Spanish fathom is 1.6718 m. The English woman is 1’83 m. These ancient measurements cannot be specified in a categorical way.