The strap is made by cutting about a 40mm wide piece of
tubing the same size as the boom to which it will be
mounted on. Weld on a long nut each side of the tube or
alternatively use a small tube and weld a nut at the end.

Split both sides with a metal saw to make the clamp
gap. If using the long nut, drill out the thread on one
side.
See Pic and drawing